Nuclear Waste Management of theOlkiluoto and Loviisa Power Plants

Annual Review 2004

The front cover shows the mouth of the access tunnel to the underground

rock characterisation facility, ONKALO, in the initial phase of excavation.

1

SUMMARY

This report describes the nuclearwaste management of the Olkiluotoand Loviisa nuclear power plants.The report includes a description ofthe status and operations of nuclearwaste management of the powercompanies in 2004, a review of thecommunication activities pertaining tonuclear waste management, and anaccount of the provisions made forfuture waste management costs.

In accordance with the decisiontaken by the Ministry of Trade andIndustry in 2003, the operations re-lated to the final disposal of spent fuelshall progress in such a way that thematerial required to apply for a con-struction licence must be ready bythe end of 2012. By the same deci-sion, the Ministry set a new interme-diate target of 2009, at which timean overview of the material intendedfor the application for a constructionlicence must be submitted. On thewhole, preparations for the final dis-posal of spent fuel are progressing inaccordance with the programme forthe pre-construction phase of the fi-nal disposal facility published in 2000and with the three-year programme“TKS-2003” pertaining to detailedresearch, development and technicaldesign published in 2003.

For the purpose of the investiga-tions at Olkiluoto for site confirma-tion, Posiva launched the VARTUresearch programme, under whichthe work of the necessary fields ofresearch (geology, geophysics, hydro-geochemistry, hydrogeology, rockmechanics and field investigations) is

planned, implemented and reported.Posiva also set up the InternationalAdvisory Group for Olkiluoto Inves-tigations, known as the INAGOGroup to assess the operations un-der the VARTU programme.

In the assessment of long-termsafety, the main emphasis in 2004was on studies into the behaviour ofengineered barriers, i.e. the coppercanister and bentonite, and on theexamination of harmful processes. Aplan and schedule were drawn up forthe safety case to be prepared in sup-port of the application for a construc-tion licence for the final disposal fa-cility.

The design documentation of fi-nal disposal canisters was updated.With regard to canister manufactur-ing technology, one of the principaldevelopment subjects continued to bethe manufacture of the cylindrical partof the copper canister from one piece,with several optional methods. Thecost estimates of the spent fuel trans-portation alternatives were updated.

Linked with the future use of theunderground rock characterisationfacility called ONKALO as a part ofthe nuclear installation, the prepara-tion of a manual for the nuclear ma-terial safeguards was launched. Thepurpose is to put the manual into useduring 2005.

In designing the repository, thepriorities included developing the low-pH grouting material, the horizontaldisposal concept and the backfillingmethods, and co-ordinating the designof the repository and ONKALO.

The first tunnel contract forONKALO was signed in the springof 2004. The contract covers exca-vation and structures of the accesstunnel to level –417 m and raise bor-ing of the shaft to level –287 m. Theexcavation work began on 29 Junewith excavation of the open cut,which was completed on 6 Septem-ber 2004. The excavation under-ground began on 22 September 2004,and by the year-end the total lengthof the tunnel was 157 m.

With regard to operating waste,the established monitoring and long-term investigations and practical mea-sures continued. Construction of thesolidification plant for wet wastesbegan in Loviisa. The plant is sched-uled for completion in 2006.

By the end of 2004, 4,683 m3 ofoperating waste had accumulated atthe Olkiluoto Power Plant, and 2,625m3 at Loviisa; 4,140 m3 of the Olki-luoto waste has been finally disposedof in the VLJ Repository; 1,234 m3

of the Loviisa waste has been dis-posed of in the low- and intermedi-ate-level waste repository at Häst-holmen.

The decommissioning plans forthe power plants were last updatedin 2003, and the next revision will bedone by the end of 2008.

The overall costs of the researchprogramme for nuclear waste man-agement of the Olkiluoto and Lovii-sa Power Plants amounted to EUR14.3 million. On the whole, the re-search programme was implementedaccording to plan.

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3

CONTENTS

sivu

SUMMARY 1

INTRODUCTION 5

SPENT FUEL MANAGEMENT 6• PRINCIPLES AND SCHEDULE 6• CURRENT STATUS OF STORAGE 6• INVESTIGATIONS AT OLKILUOTO FOR SITE CONFIRMATION 7• MONITORING THE EFFECTS OF ONKALO 12• ASSESSMENT OF LONG-TERM SAFETY 14• FINAL DISPOSAL TECHNOLOGY 16• DESIGN OF THE UNDERGROUND CHARACTERISATION

FACILITY 23

MANAGEMENT OF OPERATING WASTE 25• OLKILUOTO POWER PLANT 25• LOVIISA POWER PLANT 27• JOINT STUDIES 30

DECOMMISSIONING INVESTIGATIONS 31• OLKILUOTO POWER PLANT 31• LOVIISA POWER PLANT 32• JOINT STUDIES 32

COMMUNICATION AND CONTACTS 33

QUALITY MANAGEMENT ANDENVIRONMENTAL MANAGEMENT 34

COSTS 35

LIST OF REPORTS 2004 36

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5

INTRODUCTION

In Finland, two companies utilisenuclear energy to generate electricalpower – Teollisuuden Voima Oy (TVO)and Fortum Power and Heat Oy (here-after referred to as Fortum). In com-pliance with the Nuclear Energy Act,TVO and Fortum are liable for all ac-tivities associated with management ofthe nuclear waste they produce, for theappropriate preparation of these activi-ties and for all related costs incurred.

In accordance with the NuclearEnergy Act, the Ministry of Trade andIndustry (KTM) makes decisions on theprinciples that must be applied tonuclear waste management. KTM for-mulated these principles in its deci-

sions of 19 March 1991, 26 Septem-ber 1995 and 23 October 2003. Thedecisions provide a basis for both thepractical implementation of nuclearwaste management and the research anddevelopment related to future mea-sures.

Each company is separately re-sponsible for all measures necessaryfor the treatment and final disposal oflow- and intermediate-level operatingwaste, and for the decommissioning ofthe power plants. Posiva Oy, a companyjointly owned by TVO and Fortum, isin charge of the research and develop-ment of the final disposal of spentnuclear fuel and, ultimately, of the con-

struction and operation of the disposalfacility itself.

Posiva is also in charge of compil-ing the plan for and report on nuclearwaste management of the Olkiluoto andLoviisa nuclear power plants, both ofwhich are to be prepared annually. Asprescribed by the Nuclear Energy Actand Decree, this Annual Review 2004describes the status and operations ofnuclear waste management in 2004. Thereport also reviews communication ac-tivities pertaining to nuclear waste man-agement and the provisions made forfuture nuclear waste management costs.

At its Olkiluoto Power Plant in Eurajoki, Teollisuuden Voima Oy operates two boiling water reactors with anominal output of 840 MWe (net) each. Olkiluoto 1 (OL1) was connected to the Finnish grid in September 1978,and Olkiluoto 2 (OL2) in February 1980. In 2004, the load factors of OL1 and OL2 were 95.1% and 96.1%,respectively. The operating licences for plant units OL1 and OL2, the storage facility for low-level waste (MAJStore), the storage facility for intermediate-level waste (KAJ Store) and the interim store for spent fuel (KPA Store)will be valid until the end of 2018. The operating licence for the repository for operating waste (VLJ Repository)will be valid until the end of 2051.

Fortum Power and Heat Oy’s Loviisa Power Plant has two pressurised water reactors with a nominal output of488 MWe (net) each. Commercial operation of Loviisa 1 (LO1) began in May 1977, and that of Loviisa 2 (LO2) inJanuary 1981. In 2004, the load factors of LO1 and LO2 were 87.1% and 93.8%, respectively. The operatinglicences for plant units LO1 and LO2, and the related nuclear fuel and nuclear waste management facilities willbe valid until the end of 2007. With respect to the repository for operating waste (VLJ Repository), the operatinglicence will be valid until the end of 2055.

6

SPENT FUEL MANAGEMENT

PRINCIPLES ANDSCHEDULE

CURRENT STATUSOF STORAGE

In compliance with the Nuclear EnergyAct and the KTM decisions, prepara-tions are underway for the final disposalin Finland’s bedrock of all spent fuelfrom the Olkiluoto Power Plant and thespent fuel stored to date at the LoviisaPower Plant, as well as that which willaccumulate hereafter. In its decision of23 October 2003, KTM revised theschedule for preparations for the finaldisposal of spent fuel in such a way thatthe preliminary studies and plans re-quired for a construction licence forthe final disposal facility must be sub-mitted in 2009. Provision must be madeto submit the final studies and plans bythe end of 2012 instead of the previousdeadline of 2010. The schedule targetset for the beginning of final disposalwas kept unchanged, in 2020. In themeantime, spent fuel is stored tempo-rarily at the power plant sites.

In December 2000, the Council ofState took a Decision in Principle con-cerning the final disposal of spentnuclear fuel at Olkiluoto in Eurajoki.Parliament ratified the decision nearlyunanimously in May 2001. The final

disposal facility, consisting of an en-capsulation plant and a repository, willbe built in the 2010s. In accordancewith the Decision in Principle, an ap-plication for a construction licencemust be submitted in 2016 at the lat-est.

In 2002, a Decision in Principlewas taken to construct a new nuclearpower plant unit in Finland. At the sametime, a Decision in Principle was takenon the extended construction of a finaldisposal facility for spent nuclear fuelin such a way that the spent fuel fromthe new plant unit can also be disposedof in the facility. The waste manage-ment obligation of the new plant unitwill not begin until the commissioningof the plant towards the end of the de-cade.

Preparations for the final disposalof spent fuel progress in accordancewith the long-term programme pertain-ing to research, development and tech-nical design (TKS) published in 2001.The principal tasks of the current three-year period (2004–2006) have beendescribed in the TKS-2003 programmepublished towards the end of 2003. TheRadiation and Nuclear Safety Author-ity gave an assessment of theprogramme in October 2004.

Spent fuel from the Olkiluoto plant isstored temporarily at the plant units andin the interim store for spent fuel (KPAStore). In 2004, the storage capacity ofthe KPA Store was 7,146 assembly po-sitions. The KPA Store has sufficientcapacity for the spent fuel accumulatedduring about 30 years’ operation of theplant units. Extension of the storagewill be necessary in about 2012. De-sign work on the extension is about tobegin. The twenty-fifth refuelling ofOlkiluoto 1 and the twenty-third refu-elling of Olkiluoto 2 were carried outduring the year under review. At the endof 2004, a total of 6,050 assemblies ofspent fuel, equivalent to 1,026 tonnesof fresh uranium were stored at theOlkiluoto plant. The KPA Store housed4,838 assemblies; the pools of OL1stored 717 assemblies and those ofOL2 stored 495 assemblies.

Return transports of spent fuelfrom the Loviisa plant to Russia termi-nated at the end of 1996 owing to anamendment to the Nuclear Energy Act.Subsequently, the storage capacity at

7

INVESTIGATIONSAT OLKILUOTOFOR SITECONFIRMATION

Overview

the Loviisa plant was increased in 2000in such a way that, using racks of thecurrent type, the capacity will be suffi-cient until 2010. A study into extensionof the spent fuel storage capacity wascompleted in 2004. The study consid-ered the opportunities to enlarge spentfuel store 2 in technical and economicterms. Results of the development workprovided what are called the extensionoptions of dense and open fuel racks,which are based on the water pool tech-nology employed in Finland. The exten-sion option of dense fuel racks is basedon the storage pools currently in use,while the extension option of openracks is based on the construction offour additional pools as an extension ofthe existing ones. Invitations to tenderfor dense racks were sent to seven Finn-ish equipment manufacturers and sixforeign suppliers. The study did not re-veal any factors that would prevent theacquisition and introduction of denseracks.

At the end of 2004, a total of 2,947spent fuel assemblies, equivalent toabout 354 tonnes of fresh uranium (es-timated on the basis of the amount ofuranium contained in the spent fuel,about 336 tonnes), were stored in theLoviisa plant’s storage facilities. LO1housed 204 assemblies and LO2housed 227. The spent fuel storage fa-cilities 1 and 2 held 450 and 2,066 as-semblies, respectively.

The investigations at Olkiluoto for siteconfirmation consist of research workin many different fields, and it shouldbe possible to interpret and combinethe findings of these studies so as toprovide the basic data for developmentof the final disposal concept, design ofthe repository and assessment of thesafety. To achieve this objective, Posivalaunched what is called the VARTUprogramme, which helps gather thedocumentation obtained from the dif-ferent fields and sites of research andenables users of the information tobuild up an overall picture of the bed-rock conditions at Olkiluoto.

The VARTU programme startedoperations in the beginning of 2004,and its task is to co-ordinate the design,implementation and reporting of theinvestigations at Olkiluoto for site con-firmation during investigation phases 1and 2 of ONKALO (phase 1: investiga-tions from the ground surface beforeconstruction of the access tunnel;phase 2: construction of the access tun-nel and the ventilation raise and relatedinvestigations). The scope of theprogramme includes the investigations

from both ONKALO and the groundsurface.

The co-ordination aims to inter-sperse the research operations with theimplementation of ONKALO in thebest possible manner and to oppor-tunely serve the further design ofONKALO as well as the developmentwork on and technical design of the fi-nal disposal concept. The VARTUprogramme is therefore closely con-nected with other ONKALO -tasks,such as the design and monitoring ofONKALO. The tasks also include see-ing to the overall interpretation of thedifferent fields and sites of research(synthesis, integration). To this end, aspecial interpretation and modellingwork group entitled the Olkiluoto Mod-elling Task Force (OMTF) was set upunder the VARTU programme.

Principal Co-ordinators for eachfield of research (geology, geophysics,hydrogeochemistry, hydrogeology,rock mechanics and field investiga-tions) are responsible for the design,implementation and reporting of theVARTU research programme. A co-or-dination group, led by the ProgrammeCo-ordinator, is responsible for the co-ordination of the research, develop-ment and design tasks as well as formeeting the overall targets set for theprogramme. The members of the groupinclude the above-mentioned co-ordinators and the leader of the Mod-elling Task Force (OMTF). The co-or-dination group convened 13 times in2004.

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8

GeologyGeological investigations fromthe ground surface

The primary task of the OMTF isto interpret and model the results ofsite investigations in an integrated man-ner, which serves both the implemen-tation of ONKALO and the develop-ment work on the final disposal con-cept as well as the assessment of itslong-term safety. The OMTF consistsof four modelling groups (geology,hydrogeochemistry, hydrogeology androck mechanics), whose leaders aremembers of the OMTF’s Core Group.It is led by the head of the OMTF, andthe members also include the represen-tatives of the long-term safety groupand the VARTU programme. In 2004,the OMTF’s Core Group convened 13times. During the year under review, themost important task was to draw up theSite Descriptive Report 2004 onOlkiluoto, which constituted at thesame time the updating of the 2003Baseline Report. The report will bepublished in the first half of 2005.

In 2004, Posiva also set up the In-ternational Advisory Group forOlkiluoto Investigations, known as theINAGO Group to assess the operationsunder the VARTU programme. Thegroup comprises six members fromdifferent fields of research, and theyrepresent the waste managementorganisations of five countries. TheINAGO Group convened twice in 2004.

The Radiation and Nuclear SafetyAuthority (STUK), supported by inter-national groups of experts, assessed theprogress of the research done under theVARTU programme. In 2004, STUKdrew up a list of open issues, whosefirst version includes a total of 36 is-sues pertaining to the research, moni-toring and modelling related toONKALO. The open issues have beenclassified into three urgency catego-ries: those to be settled immediately(in about a year), those to be settled ina few years, and those to be settled be-fore applying for a building permit.Once an issue has been settled in anacceptable manner, it can be removedfrom the list. New issues can also beput on the list as the investigations forsite confirmation progress. The pur-pose is to deal with the open issues atmeetings to be arranged twice a year.The first monitoring meeting of thiskind was held in the autumn of 2004.

Investigations in accordance withthe VARTU programme carried out in2004 are discussed below by field ofresearch.

During 2004, the geological propertiesof the Olkiluoto bedrock were studiedfrom the ground surface with the aid ofoutcrop mapping, investigationtrenches and drillings. The purpose ofthe investigations was to establish theproperties of the geological features inthe Olkiluoto area and to specify thecurrent bedrock model. Furthermore,the investigations are aimed to increasethe geological predictability.

Geological outcrop mapping wasconcentrated on the eastern part ofOlkiluoto, and their purpose was to gaindeeper insight into the different defor-mation phases of the bedrock and thedistribution of rock types on the island.During the outcrop mapping, effortswere made to systematically review alloutcrops in the eastern part of the is-land and to survey the structures thatcould be detected from them, such asschistosity, folding and fracturing. Theoutcrop observations totalled morethan 200.

Four new investigation trenches(TK8-TK11) were dug at the Olkiluotoinvestigation site; their total length wassome 1,200 metres. The rock types, allfractures and the detectable plasticstructures (e.g. schistosity and foldaxes) were analysed from the trenches.

Investigation trench TK4 dug in thesouth-north direction in the central partof the island in 2003 was extended tothe north as investigation trench TK8.The purpose of the trench was to pro-vide deeper insight into the 2D and 3Dstructure of the large fold structurethat could be detected with geophysi-cal methods, to establish the fracturesystematics of bedrock in the northernpart of the island and to investigate theproperties of structures RH20A andRH20B. Furthermore, the trench helpedsharpen the picture of the distributionof rock types on the island. The final

length of the trench was 760 metres,and about 1,700 fractures in all wereanalysed from the trench.

Investigation trench TK9 was dugin the central part of the island, in thevicinity of investigation trench TK3 dugin 2002. The purpose of the investiga-tion trench was to provide new insightinto the structure of the bedrock and thefracture systematics in the western partof the Olkiluoto investigation site. Inaddition, the purpose was to obtain ad-ditional information on the propertiesof the fracture zone detected in trenchTK3. Examination of the properties ofthe structure concerned is of great im-portance in designing the location ofthe repository west of the investigationsite.

Two smaller trenches were also dugat Olkiluoto. Investigation trench TK10was dug in the eastern part of theOlkiluoto investigation site, betweenboreholes OL-KR9 and OL-KR11, onthe basis of the outcrop mapping andgeophysical anomalies. The end of thepotential large fold structure that canbe detected with geophysical methodsis exactly located in the area concerned,and what is more the outcrop mappingconducted during 2004 support theabove-mentioned geophysical observa-tion. The trench is aimed to establishthe geometry of the fold structure con-cerned and its relation to the brittlestructures discovered on the island.With respect to trench TK10, geologi-cal surveys are still unfinished and con-tinue during 2005.

Investigation trench TK11 was dugat the Olkiluoto investigation site dur-ing the construction of the storage hallfoundations completed in the summer.The investigation trench is locatedalong the line of the access tunnel toONKALO and partly above investiga-tion trench TK7. All fractures, rocktypes and deformation structures wereanalysed from the trench. The co-ordi-nates of each fracture were defined withthe aid of a tacheometer. The acquireddata helped make a detailed fracturemap of the trench, which can be furtherutilised in studying the fracture system-atics in the area and in predicting thefracturing of the access tunnel toONKALO. More than 2,000 fractureobservations were made from the

9

Geological mapping ofONKALO Geological modelling

Hydrogeochemistry

trench. Furthermore, a brittle fault inthe north-south direction was detectedin the trench, whose relative vergencescould be determined on the basis ofgeological observations. The observa-tions show that the east side of the faulthad moved at least 2 metres northwardsin relation to the west side of the fault.

Five new deep boreholes (OL-KR29–OL-KR33) were drilled at theOlkiluoto investigation site; the lengthof the boreholes totalled some 1,660metres. In addition, existing boreholeOL-KR23 was extended to a length of460 metres. With regard to drillings,the main emphasis was placed on speci-fication of the properties and continu-ity of structures RH19A, RH19B,RH20A and RH20B. Moreover, the pur-pose of borehole OL-KR33 was to pro-vide new insight into the strike andproperties of the fracture detected ininvestigation trench TK3 in deeperparts of the bedrock and into the struc-ture of bedrock in the western part ofOlkiluoto. On the other hand, the pur-pose of OL-KR29 was to specify theproperties of the bedrock in the south-ern part of Olkiluoto, and this boreholewill serve as what is called the moni-toring borehole south of ONKALO.

The new research hall in the areaof ONKALO was put into use in thesummer. In the research hall there is,for instance, a drill core laboratory,which has considerably accelerated theanalysis of drill cores.

Geological mapping of the excavatedsurfaces began as part of the excava-tion work of ONKALO. The open cutleading to ONKALO was mapped first.The mapping included, for example,documentation of the rock types androck fracturing in the same manner asin tunnel mapping. When the tunnelexcavation had got started towards theend of September, the tunnel roof andwalls were mapped after every excava-tion round. During the mapping, thedata recorded included, e.g., the rocktype, alteration/degradation, bedrockfracturing, schistosity and other fea-tures of structural geology, water seep-

ages and fracture zones. The observa-tions are bound to the benchmarks inthe tunnel and their actual co-ordinates.About 150 metres of the tunnel weremapped during 2004, which meansmore than 2,500 square metres interms of area. More than 2,100 obser-vations of different types (fracturing,schistosity, fold axis, etc.) were madefrom the mapped section and, in addi-tion, exact co-ordinates were measuredfor long fractures and structures. Inpractice, the mapping is performed bygeologists working in pairs in threeshifts on discontinuous three-shiftwork. The mapping progresses simul-taneously with the excavation work,which requires that the work is inte-grated and the mapping developed so asto be flexible and appropriate. Further-more, the data produced shall be avail-able to the designers and modellinggroups of the tunnel almost immedi-ately after the mapping.

The first pilot borehole ofONKALO (OL-PH1) with a length ofabout 160 metres was completed in thebeginning of the year. The purpose ofthe pilot borehole was to verify the re-sults of the previous investigations car-ried out along the tunnel line and to pro-vide initial data for the designers of thegrouting and reinforcement ofONKALO. In December, another pilotborehole (ONK-PH2) with a length of122 metres was drilled in ONKALO.Both the pilot boreholes kept inside thetunnel profile, which was set as an ob-jective.

The geological modelling group, co-ordinated by the OMTF (OlkiluotoModelling Task Force), began opera-tions. During the first part of the year,Posiva brought a new 3D-modellingprogram, Surpac, into operation. In au-tumn, the biggest task was the “predic-tion-outcome” research work begunsimultaneously with the excavation ofONKALO, which predicts geologicalfeatures discovered in the tunnel in twoways. Prediction A consists of the pre-diction made on the basis of the exist-ing model and other research data, whileprediction B is based on the data ob-tained from the pilot borehole. These

predictions help test how well it is pos-sible to predict the geology at Olkiluotoand its special features to be able tolater select the correct investigationmethod for locating the repository bed-rock and assessing its suitability for thepurpose of designing the repository lay-out and its construction. Both predic-tions were made along the first pilotborehole, PH1, during autumn. The pre-dictions were compared with the tun-nel mapping data, and preliminary re-sults show that particularly the predic-tion made on the basis of the pilot bore-hole held true with respect to the frac-ture zones and fracturing of the bed-rock.

In spring, the modelling group per-formed a lineament interpretation onthe Forsmark investigation site jointlywith SKB. The corresponding interpre-tation on the Olkiluoto site began in theautumn. The interpretation is based onthe updating of topographic lineamentsand the interpretation of geophysicallineaments. In the next phase, these in-terpretations will be combined to pro-vide a better picture of the lineament,for instance in the sea areas, and thusreduce uncertainties. Lineament inter-pretation is needed for studies into po-tential extension of the investigationarea as well as for geological andhydrogeological modelling.

The hydrogeochemical description ofOlkiluoto (Pitkänen et al. Posiva 2003-07) published in 2003 was comple-mented by the hydrogeochemical ma-terial gathered by the summer of 2004.The comments made on the descriptionof the baseline were also taken intoaccount in the updating, as far as pos-sible. The description represents thecurrent baseline at Olkiluoto before theconstruction of ONKALO begins. The3D model published in 2003 was alsoupdated with new results and the calcu-lation of the model was further devel-oped. The purpose is to later use themodel to visualise the disturbancescaused by ONKALO.

Hydrogeochemical investigationsfurther concentrated on studies into theregional distribution of the salinity, the

10

Geohydrology

Measurements andinterpretation

Modelling

definition of dissolved gases and thebaseline in the investigation area, sincethe data were needed to update the de-scription of the hydrogeochemicalbaseline. A total of 29 groundwatersamples were taken from deep bore-holes. Of these, four water samplesbelonged to the monitoring programmeof the long-term pumping test of OL-KR6 and ten samples to the monitor-ing programme. Dissolved gases wereanalysed from a total of 19 watersamples and microbes from fivesamples. The results obtained early inthe year were further used for verifica-tion and finishing of the description ofthe hydrogeochemical baseline atOlkiluoto. The results will be reportedin English in the first part of 2005.

Water sampling from the shallowboreholes drilled in the bedrock andfrom the standpipes installed in theground continued in accordance withthe monitoring programme. In thespring, samples were taken from tensampling points, and microbe sampleswere also taken at the same time. Thesamples taken in the autumn totalled26. In addition, the purpose of the wa-ter sampling was to examine the sea-sonal variations and any disturbancescaused during the construction ofONKALO. The results will also be re-ported in English in the first part of2005.

Hydrogeological measurements werecarried out from the observation tubesinstalled in the ground, from the shal-low drillholes and boreholes and fromthe deep boreholes. More observationtubes were installed and more shallowboreholes were drilled to improve thearea coverage of the observationpoints. Previous measurement resultswere also analysed and reported. In-deed, deeper insight was gained into thesurface-hydrology, and some of themeasurements were included in thesystematic monitoring programme(OMO).

An updated summary was reportedof the results of the long-term pump-ing test conducted in borehole OL-

KR6, and the test was underwaythroughout the year. A decision wastaken to continue the test until the cal-culated coverage of the test is exten-sive enough and essential changes in thepumping waters are no longer evident.The occurrence of the different watertypes, particularly the infiltrating fresh-water, current seawater, more salinegroundwater and water typical of theLitorina Sea can be identified near thecoastline of Olkiluoto Island on thebasis of the preliminary results.

Hydraulic conductivity propertiesof the principal tight bedrock sectionsof Olkiluoto Island were measured withthe hydraulic testing unit (HTU) fromboreholes KR12–KR14. The testingunit was developed by adding to it a lo-cation option based on the single-pointresistance method, by which the com-parison between the various measure-ments with respect to the depth posi-tion is on a solid basis.

Simultaneous examination of digi-tal images, other borehole data and hy-draulic measurement results has en-abled the properties of single hydrau-lically conductive fractures to be iden-tified and determined for a given frac-ture. Data of this kind helps give a bet-ter picture of the flow of groundwateron the scale of single fractures.

The soil in the area of ONKALOand the hydrological observations madethere were studied to assess any effectson surface hydrology produced by theconstruction of ONKALO. Owing tothe vicinity of a Natura 2000 site, spe-cial examination of this kind was nec-essary. A summary of the studies hasbeen presented in a working report.

A pressure interference test wascarried out between boreholes OL-KR14–OL-KR18 during the year underreview. This test supplemented the flowinterference test conducted in 2002.For the pressure interference test, ob-servation boreholes were plugged intosections with the aid of multi-packerequipment, and the development ofpressure in each packer interval wasmeasured with pressure transducers.When analysing the results later, theresults of these different interferencetests will be compared with each other,and the usability of the data obtainedfrom the different tests for understand-ing the flow of groundwater will be as-

sessed. Preliminary evaluations showthat this test also supports the pictureof only few single hydraulically con-ductive fractures built up previously.

Previous modelling studies performedfor design of the layout of ONKALOwere reported as a working report.These studies helped identify the essen-tial features of the disturbances causedand could thus be taken into account inthe design. However, the actual extentof the disturbance will depend on theoutcome of the final grouting measuresimplemented during construction.

With regard to the groundwaterflow modelling, the main task was togain a better understanding of the siteand to reduce the uncertainties, whichconstituted the objective set for theinvestigations for site confirmation.Co-operation with the other fields ofresearch, such as geology, hydrogeo-chemisty and rock mechanics, waslaunched within the Olkiluoto Model-ling Task Force (OMTF). At first, theflow modelling and hydrogeochemistrygroups attempted to work out a com-patible idea common to the variousfields of research. The work consistedof both updating the picture of thebaseline and performing the first ad-vance modellings of the effects of theconstruction of ONKALO where thefirst kilometre of the tunnel reaches adepth of 100 metres. The modellingwas carried out in 2004 and the reporthas been completed. A consistent sitedescription report of the disposal site,which also includes a geohydrologicaldescription, will be completed in early2005.

The modelling of groundwater flowin the demanding situation where thedensity of groundwater and the ground-water level vary locally as well as tem-porally, owing to the flow, has requiredcoupling the modelling of both the flowand the migration of dissolved matter(salt) as a transient. Success in devel-oping a model for a purpose as com-plex as this has been a major achieve-ment. In modelling the final disposalsituation, the heat generated by wastewill be included as well. The currentdevelopment level will also enable theheat and the consequent alteration in

11

Rock mechanics

Environmental studies

Equipment and methodsdensity to be taken into account in themodelling.

With respect to rock mechanics, whatis called the rock mechanics group wasset up, whose purpose is to design andimplement the rock mechanical tasksrequired by the OMTF. The group’stasks included, for example, gatheringa summary of all the rock mechanicalstudies conducted before 2005, carry-ing out a technical audit of the numeri-cal modelling performed previously,thus striving to enhance the strategy ofnumerical modelling, building up a pic-ture library of the R/RH structures pen-etrated by investigation boreholes, ex-amining the connection between thegeological structures and the stress,ensuring the acquisition of essentialrock mechanical mapping data duringthe construction of ONKALO, and writ-ing the chapter that deals with rockmechanics in the OMTF site report.

The point load test results obtainedfrom the investigation boreholesamples drilled from the ground sur-face were gathered in a separate report.The strength values calculated from thepoint load index were divided into sixrock types, and the variation betweenthe boreholes and with respect to thedepth was also studied. The purpose isto further expand the scope of the workin 2005 while taking the observationsof schistosity and the load directionwith respect to schistosity into accountas well as establishing their correlationwith the strength values.

Strength and deformation proper-ties were determined from the samplestaken from investigation borehole OL-KR24 (the ventilation raise borehole ofONKALO). The samples were takenfrom depths of 400–450 m, corre-sponding to the main characterisationlevel of ONKALO. The test programmeincluded uniaxial and triaxial tests andtension tests. Some of the uniaxial testswere what are called anisotropy deter-minations, while some also includedthe measurements of acoustic emis-sion.

A study was launched at HelsinkiUniversity of Technology whose pur-pose is to study whether the stress can

be assessed by loading divergent drillcore samples and by observing themwith the aid of acoustic emission, orwhat is called the Kaiser phenomenon.The study to be conducted as a master’sthesis will be completed during 2005.

The monitoring programme launchedduring the year under review includesmost of the environmental studies. Thebasic survey of the fauna at Olkiluotowas supplemented by studying the spe-cies and number of smaller mammals,carabid beetles (Carabidae), beetles(Coleoptera) and bats. The comprehen-sive survey of forests at Olkiluoto,launched in 2002, continued with thefirst phase of the forest plot inventory,which consisted of gathering data on thetree stand from about 550 observationpoints distributed at regular locationson the island. Routine monitoring ofthe composition of rainwater, snow andsoil-water continued normally, as didthe snow and frost observations. In ad-dition, the monitoring data for the pastyear on the weather conditions, themarine ecosystems and the radioactiv-ity of the environment gathered byTeollisuuden Voima Oy were alsostored in Posiva’s archive for subse-quent detailed examination.

The monitoring network of the en-vironment was improved by building aweather mast in the observation areaestablished in 2003 for the purpose ofmonitoring, for instance, the microcli-mate of the forest stand. Furthermore,this observation area was comple-mented and a corresponding observa-tion area was established in the oldspruce wood located in the same catch-ment area.

To improve the handling of moni-toring and other environmentalsamples, the working point in the labo-ratory of the research hall built as partof the ONKALO site, which is intendedfor the handling of environmentalsamples, was brought into operationduring the year under review. The pre-treatment facilities provided there en-sure increasingly reliably the quality ofthe samples up to the actual analysinglaboratory.

Development work on the equipmentknown as TERO intended to measure thethermal properties of the bedrock insitu continued, and a report on the con-struction of the equipment was com-pleted. Development work on the inter-pretation software of the borehole mea-suring equipment was also launched andthe first test measurements in the fieldwere conducted in investigation bore-hole OL-KR2 at Olkiluoto. After ini-tial problems, the field measurementswere technically successful. Posivaalso had preliminary discussions aboutmeasurements at SKB’s investigationsites.

Development work on the interpre-tation of results from the rock stressmeasurement based on the overcoringmethod, carried out jointly with SKB,continued. The development worklinked with continuous, isotropic ma-terial was practically finished. The pur-pose is to complete the reporting inearly 2005. Design of the developmentwork on the interpretation tools of thenext phase, i.e. anisotropic material,began, and the work was agreed to startin the beginning of 2005.

The results of the first developmentphase of the mass spectrometry (MS)method, which enables determinationof the gases dissolved in the ground-water, were reported. The developmentwork otherwise continued to mainlyfocus on the analysis of gases from thegas phase. In the latter part of the year,the work proceeded to test the deter-mination of gases from the liquid phaseusing membrane technology. The re-sults of the method development willbe reported in 2005.

The single-point resistance mea-surement option of the hydraulic test-ing unit (HTU) was put into routine use.The program was further developed insuch a manner that comparison with thecorresponding measurements con-ducted with the differential flow mea-surement unit is possible during mea-surements, and the data provided byboth methods are shown on the displaysimultaneously. To improve the qualityof the data, rotation speed control ofthe winch was installed in the hydrau-lic testing unit. This device enables the

12

Integration

movement of the borehole equipmentat half velocity, or at the same velocityas it is possible to move the differen-tial flow measurement unit. The newelectronic cards were put into use, butproblems arose in their introduction.Settlement of the problems is beingcontinued in early 2005.

A new differential flow measure-ment unit was built during the year un-der review, and its calibration was com-pleted towards the year-end. The unitwill be brought into operation in 2005.The purpose of building the equipmentis to better meet the increasing mea-surement needs in ONKALO and aboveground. The interpretation program ofthe differential flow measurement unitwas upgraded to be better suitable formeasurements in ONKALO. In addi-tion, monitoring programs of the en-crustation of the EC transducer and thecable tension were developed.

The field tests of the transverseflow measurement equipment were car-ried out in investigation boreholeOL-KR16 and most of the results wereseen to be successful. The rubberguides were found to be too stiff, andconsequently they will be further im-proved. To test the equipment underlaboratory conditions and to provide ademonstration site, what is called theartificial fracture will be built, whichwill enable the visualisation of the mi-gration of water in the fracture andthrough the flow transducer of theequipment with the aid of a visibletracer. The design of the artificial frac-ture began.

Additional pressure vessels weremanufactured for the PAVE equipment,one with a volume of 300 ml and twowith a volume of 150 ml. The hosewinch manufactured in 1999 to facili-tate lowering the equipment into theinvestigation borehole was modernisedby reducing the size of the winch andby installing it in the frame of a trailer.Furthermore, two new sets of fieldmeasurement equipment were built forwater sampling to be performed fromthe ground surface. Extension rods,whose material is carbon fibre, weremanufactured for the borehole instal-lation work to be made in ONKALO.

Tests showed that the carbon fibre rodswere very suitable for the borehole in-stallation work, and they can replace theweaker and heavier aluminium rods.

The nitrogen generator, which re-placed the nitrogen batteries, was putinto production use for the pumpingwith the PAVE equipment after test op-eration. In the autumn, the gaseous ni-trogen produced with the nitrogen gen-erator was subjected to quality analy-ses, which showed that the purity gradewas within the promised limits.

Equipment plans were made formonitoring the groundwaters inONKALO. This automatic measuringsystem of the ONKALO groundwatersconsists of automatically monitoringthe parameters of both the measuringweirs and the groundwater stations.During the year under review, the plansprogressed to such a stage that the sys-tem supplier was selected at the end ofthe year. The implementation of thesystem will start in the beginning of2005. To test the measuring weir box,one box with a V-shaped opening wasmanufactured of steel, and it was cali-brated using V-shaped openings of dif-ferent sizes.

Development work on the gas sam-pling methods was carried out as botha literature study and practical tests.Gas samples were taken as part of thePAVE -pumping from the ground sur-face directly into the PAVE vessel. Thesamples were measured with the aid ofa mass spectrometer, whose methoddevelopment also continues to be un-derway. The results were good, so fur-ther development work on the gas sam-pling method is being continued in2005. The results of the developmentwork will be reported during 2005.

The Olkiluoto Modelling Task Force(OMTF) began operations with a viewto integrating the modelling of the dif-ferent fields of research and to form-ing a common, compatible and consis-tent opinion about the final disposalsite on the basis of the modelling re-sults in the different fields. The basesfor the integration and its objectives

have been described in the Under-ground Characterisation and ResearchProgramme (UCRP). Practical ar-rangements of the work and aspects tobe considered in it have also been de-scribed in the TKS-2003 programme.

Having operated for about a year,the OMTF drew up a plan for its opera-tions and started co-operation betweenthe fields of research to produce thefirst common and consistent descrip-tion of the final disposal site, or a sitereport. Essential parts of the reportwere completed, and the report will beready for press and published in early2005.

Launching the work of the model-ling groups of the different fields ofresearch, i.e. geology, rock mechanics,hydrology and geochemistry, has takenthe bulk of the time, but the needs forinformation exchange and the forms ofinteraction between the fields have nowbeen surveyed and described in the sitereport.

The integration advanced farthest inthe co-operation with the fields of hy-drology and geochemistry. It was pos-sible to provide a consistent descrip-tion of the palaeohydrological andpalaeogeochemical evolution of Olki-luoto Island that tallies with the sitedata. The integration is a very labori-ous process, and the nature and numberof parameters, hypotheses and simpli-fications necessary for the modellingcontribute to the opportunity to suc-ceed in fitting the modelling results tothe measured ones. However, apparentcontradictions can be eliminated byconsidering the modelling results ofany field iteratively, and comparingthem with the results of other fields ofresearch.

The research results to be obtainedfrom ONKALO, combined with othersite data will eliminate current defi-ciencies in the basic data required bythe models. It can be expected that, inthe next round of integration, the resultswill be specified, thus building confi-dence in their ability to describe futuredevelopment and providing an increas-ingly solid basis for presenting thesafety case.

13

The intensive observation area of a forest. Duckboards have been built in the area in ordernot to disturb the monitoring of water infiltrating into the soil. The orange rain-watercollectors and the green forest litter collectors help monitor the properties of the materialfalling onto the ground. The structure of the observation area is the same as in the pan-European monitoring programme of the health of forests (level II), whose observationareas number 31 all over Finland, thus providing excellent reference material.

In 2004, the previous studies into the fauna at Olkiluoto were supplemented by fieldinventories and interviews with local hunters. In terms of its species, Olkiluoto does notvery much differ from the rest of south-western Finland.(Photo: Juha Leppävuori, Metsätähti Ltd.)

14

ASSESSMENT OFLONG-TERMSAFETY

Bentonite studies

Studies on the performanceof engineered barriers

Other investigations in thenear-field

MONITORING THEEFFECTS OFONKALO

Any effects produced by the construc-tion of ONKALO are being monitoredby means of a monitoring programmespecially drawn up for this purpose. Themonitoring programme consists ofrock mechanical, geohydrological andhydrogeochemical monitoring as wellas monitoring of the environment andforeign substances. As the excavationof ONKALO progresses, measure-ments will also be conducted under-ground, but the measurements and in-vestigations carried out in 2004 tookplace from the ground surface.

The rock mechanical monitoringprogramme comprised the measure-ments of the GPS stations and the mi-croseismic stations. Geohydrologicalmonitoring was performed in both openand multi-plugged boreholes by mea-suring the groundwater level and pres-sure head. In addition to these, mea-surements pertained to precipitation(including snow), seawater level, frostthickness and surface runoff. The scopeof geochemical monitoring includedwater sampling from open and multi-plugged boreholes, sampling from shal-low boreholes and groundwater pipes,and monitoring the chemistry of thewater pumped from ONKALO. Thenatriumfluoresceine content of the wa-ter used for the excavation of ONKALOwas also measured.

Potential changes occurring in theenvironment were monitored by ob-serving the water circulation in a for-est stand, by studying the vegetation andsmall animals, and by monitoring thecondition of household water wells. Inaddition, the amount of dust and thenoise level were measured, and aerialphotographs were taken of the area.

A materials manual was drawn upof the permissible substances used forthe construction of ONKALO, and arecord was kept of the amounts of ma-terials used in ONKALO.

The construction of ONKALO hasproduced no effect on the monitoringresults.

Engineered barriers constitute an im-portant factor in ensuring the long-termsafety in Posiva’s safety concept. Theconcept description included in theTKS-2003 programme states that safetyis primarily based on the long-term iso-lation of radionuclides in waste canis-ters and on the engineered barriers thatensure the integrity of these canistersas well as on the natural conditions andprocesses. The performance studieshave therefore been focused on estab-lishing the behaviour of the copper can-ister and its protective bentonite and onexamining the harmful processes. Thefollowing subjects, in particular, weredealt with in Posiva’s own investiga-tions and in studies conducted as inter-national joint projects in 2004.

The high pH released from cement hasbeen assessed to produce detrimentaleffects on the mineralogical propertiesof bentonite, thus reducing, for ex-ample, the swelling pressure. An inter-national working meeting, which dis-cussed interaction between cement andbentonite, was arranged in Tokyo inApril 2004 as a co-operation project ofNUMO and Posiva (Posiva’s WorkingReport 2004-25). Interactions betweencement and bentonite were also inves-tigated within the EU project namedECOCLAY II. The final report of theproject was delayed over a year, but thefinal version has now been completedand the report will be published in thebeginning of 2005. The Finnish contri-bution to the studies will be reportedat roughly the same time.

Extensive studies into other pro-cesses occurring in bentonite over along time are being conducted in theLOT test (Long-Term Test of BufferMaterial). The tests begun in 1999 havebeen planned to last for 1, 5 and 20years. In 2004, preparations were madeto analyse the second test borehole,which will probably take place in 2005.In a larger-scale test, under the FEBEX

II project, Posiva took part in assess-ing the obtained results and in final re-porting. A summary report of theproject is likely to be completed in thebeginning of 2005. Monitoring of thislong-term test will continue under theEU’s NF-PRO project.

In 2003, SKB and Posiva jointlylaunched a large-scale test pertainingto the gas injection of bentonite buffer.The objective of this internationalLASGIT project is to carry out gas in-jection tests of moistened bentonitebuffer on a large scale and under real-istic conditions, and to interpret theresults obtained from them. The objec-tive is to quantitatively establish thephysical phenomenon linked with thegas migration process and to validatethe modelling of the gas migration pro-cess. The test arrangements include afinal disposal hole at the Äspö HardRock Laboratory. A bentonite buffer inaccordance with the KBS-3V conceptand a canister fitted with water and gassupply systems and with versatile instru-mentation will be placed in the finaldisposal hole. The systems and compo-nents were manufactured in 2004 andthey were calibrated and tested in theresearch facility towards the end of theyear. The actual installation of theequipment in the final disposal holewill take place in January 2005. Theinstallation and the sealing of the holewill be followed by the moisteningphase of the bentonite, which will lastfor about two years, after which vari-ous gas injection tests will be con-ducted in about 2007.

Phenomena in the near-field and thebehaviour of engineered barriers as awhole were tested and demonstrated inthe EU’s “Prototype Repository”project, which ended in 2004. The KBS-3 final disposal concept was studied ina sealed final disposal tunnel in a full-scale long-term test. Posiva and theTechnical Research Centre of Finland(VTT) were involved in developing theconceptual and mathematical model-ling of engineered barriers. A reportwas drawn up on the geochemicalchanges that occur during the moisten-ing of the tunnel backfilling materialand bentonite buffer. The report also

15

The bedrock as a barrier

Concepts and the safety case

deals with time-dependent changes thattake place in the engineered barrier sys-tem on the edges of the repository.Until further notice, SKB will continuewith this work as its internal project.Posiva will continue co-operating withSKB in 2005 and model changes in theporewater of the buffer and backfillingmaterials.

The performance of engineeredbarriers and the requirements set forthem are handled more extensively ininternational co-operation in the annualworking meetings of the NEA’s “Engi-neering barrier systems” project.

The project “Understanding andPhysical and Numerical Modelling ofthe Key Processes in the Near-Field,and Their Couplings for Different HostRocks and Repository Strategies (NF-PRO)”, which is included in the EU’ssixth framework programme, waslaunched in 2004. The total volume ofthe four-year project is some EUR 16million, and the participants include 40waste management organisations andresearch institutes. The contributionsof Posiva and the research institutessupported by it concern studies into

- the effect of alpha radiolysis ondegradation of the fuel matrix;

- the stability of the fuel matrixunder high pH conditions;

- the evolution of the porewaterchemistry of bentonite (pH, Eh,ionic strength);

- interactions between thecorrosion products of copper andiron and bentonite;

- the thermohydromechanical(THM) modelling of the KBS-3Vfinal disposal concept. Themodelling work was mostlycarried out in 2004 and it will bereported in 2005.

- the evolution, mass and energybalances, energy flows and perfor-mance analysis of the near-field.

The studies will be reported laterin the manner described in the projectplan. The work also includes integrat-ing the results and assessing them fromthe viewpoint of long-term safety.

SKB and Posiva jointly continuedexperimental corrosion research par-ticularly in a saline groundwater envi-ronment. The investigation carried outin Canada continued, which pertains tomodelling the behaviour of the corro-sion potential of copper in compacted

bentonite containing sulphide on thebasis of experimental results. Further-more, a study was launched with a viewto establishing the stress corrosion ofcopper caused by acetate. Investigationsinto the redox conditions prevailing inbentonite and their measuring methodsalso continued.

The EU project named “RETROCK”,which studied the migration and reten-tion occurring in the bedrock, was com-pleted in 2004 and completion of thefinal reports is underway. These exten-sive studies concerned the conceptslinked with migration, and their mod-elling.

International co-operation on thestudies into the migration phenomenacontinued at the Äspö Hard Rock Labo-ratory. New results were obtained fromthe TRUE Block Scale tests in order formodelling. The Task Force for Ground-water Flow and Solute Transport con-tinued to focus on studies into hetero-geneity as well as the extrapolations ofboth flow and migration for a situationcorresponding to the final disposal con-ditions.

Sorption tests continued by study-ing the retention of europium on rocksurfaces treated with Cs-containing sa-line Olkiluoto waters. After a fairlyrapid initial outlet, a significant propor-tion of Eu, whose retention time is con-siderably longer, remained in the co-lumn. The test will be continued in or-der to sharpen the picture of the reduc-tion velocity of the content of releasedEu and possibly the reasons for the re-tention. To gain a better understandingof the sorption of caesium, studies con-centrated on the exchangeable cationsof the biotite fractions separated fromcore samples and on the sorption iso-therms of Na, Ca and Cs.

Research aimed at defining thesorption mechanisms of europium andamericium continued by studying theirretention in kaolinite. The research willbe continued within the FUNMIGproject, which is being launched. In2004, Posiva continued to be involvedin the work of the second phase of theNEA’s “Sorption Forum” project andthe third phase of the TDB (Thermody-namic Data Base) project. The final re-port on the work done during the sec-ond phase of the “Sorption Forum”

project is being completed in the firstpart of 2005.

Posiva was involved in the prepa-ration phase of the FUNMIG (Funda-mental Processes of Radionuclide Mi-gration) project, which is included inthe EU’s sixth framework programme.The objective of the FUNMIG projectis to gain a basic understanding of mi-gration in the geosphere, taking accountof the final disposal concepts devel-oped in different countries and the pre-vailing bedrock conditions. The projectalso aims to introduce the latest avail-able knowledge about the migrationprocesses as general tools and modelsfor the assessments of long-termsafety. The project was launched in thebeginning of 2005 and it will be com-pleted at the end of 2008. The partici-pants in the project include about 50organisations in all from differentcountries. In Finland, the University ofHelsinki, the Technical Research Cen-tre of Finland (VTT) and Helsinki Uni-versity of Technology are involved inthe project in addition to Posiva. TheFinnish contribution to the investiga-tions consists, for instance, of exam-ining the sorption of Ni, Am and Eu, thesorption mechanisms and the chemis-try of minerals that dominate the reten-tion in rocks as well as of modellingthe results. Furthermore, studies arebeing conducted to establish the oppor-tunities to utilise redox-sensitive natu-ral materials to discover and interpretthe redox changes in the bedrock. De-velopment work carried out in Finlandalso includes methods for determiningthe porosity and pore structure of rock.

Posiva and SKB jointly launched a studyconcerning the horizontal location ofthe canister, which is scheduled for2004–2007. In the KBS-3H concept,the canister and bentonite blocks arepacked into perforated steel drums andinstalled in about 200-m-long horizon-tal disposal tunnels. The objective is toestablish the suitability of the KBS-3Hconcept and to technically demonstratethe feasibility in practice. To this end,two full-scale disposal tunnels will bedrilled and the manufacture of the in-stallation equipment for the canistersand bentonite blocks will be commis-sioned.

16

Biosphere studies

Safety analysis

FINAL DISPOSALTECHNOLOGY

General

Canister design

Guidelines for the biosphere studiesand modelling were further defined onthe basis of the needs for a safety analy-sis necessary for the application for aconstruction licence in what is calledthe safety case plan, which will be pub-lished in the first part of 2005.

The project, which will run overmany years and aims to describe thefuture of the Olkiluoto biosphere, be-gan by establishing the location of thecoastline and the ground level in thearea in different eras. In the beginningof 2005, a summary report will be com-pleted on the data gathered from thesoil investigations at Olkiluoto, particu-larly from the viewpoint of the model-ling interface of geosphere and bio-sphere. The readiness for modellingwas further stepped up jointly with SKBby continuing the development of thetool tailored for the Matlab/Simulinkcalculation environment begun in 2003.In addition, a master’s thesis waslaunched towards the end of the year incollaboration with the University ofKuopio about the radioactivity of for-est ecosystems.

The second year of operation of theBIOPROTA project, partly financed byPosiva, ended in autumn 2004, and pro-duced useful work material. The jointproject of the nuclear waste manage-ment organisations concentrates onestablishing the key issues of bio-sphere modelling. The project will bereorganised and it is being continued in2005 partly with previous themes andpartly with new ones.

Posiva continued to monitor theprogress of other international projectslinked with biosphere modelling. It wasalso involved in the work of the end usergroup of the ERICA project dealing withthe assessment of radiation exposure ofthe environment and in the work of theFinnish backers of the projectorganised by the Ministry of the Envi-ronment. Moreover, Posiva and theFinnish Forest Research Institute at-tended the conference on radioecology

A plan and general schedule were drawnup for the safety case to be prepared insupport of the application for a con-struction licence for the repository,which will be published in the Posivaseries of reports in the beginning of2005. The safety case constitutes asummary of the analyses and other evi-dence that demonstrates the final dis-posal concept to be safe. The safetycase will be compiled in a report pack-age containing about ten main reports,which are to be updated at certain in-tervals. The Site report will form thebasis in terms of geosciences and con-tain a description of the present condi-tions in the Olkiluoto bedrock, the pre-vious evolution of the conditions andthe changes that the construction of thefirst phase of ONKALO and the reposi-tory will effect before operation of therepository begins in 2020. The techno-logical basis will be provided by thereports that describe and justify theProperties of spent fuel, the Canisterand the Repository. The scientific cor-nerstones of the safety case will be theProcess report, which will describe thephenomena and events that affect thefunctioning of the final disposal sys-tem, and the report on the Developmentof the final disposal site and the re-pository. The last-mentioned reportwill describe and analyse the develop-ment of the final disposal system fromthe disposal of the first canisters untilthe very distant future (some millionyears). Radiation safety and compli-ance with the related regulations issuedby the authorities will be discussed infour reports: the Biosphere, the Re-lease of radionuclides (a numericalsafety analysis), Supplementary safetystudies (for example, natural ana-logues) and the Summary, in which thesafety case will be gathered.

The facility description report pub-lished by Posiva at the end of 2003 wastranslated into English. The cost esti-mate, which is based on the facility de-sign, was made during 2004 and it willbe published as a report in English in2005. Work on the development anddesign linked with final disposal is be-ing continued towards the next interme-diate stage in 2006, when the updatedfacility designs and facility descriptionwill be published.

Close collaboration with SKB con-tinued, and the projects carried outjointly number several tens. Posivaclosely monitors SKB’s design projectof the encapsulation plant.

The canister design documentation wasupdated. The design documents de-scribe the detailed structure of the can-isters, the canister manufacturing tech-nology, including the manufacturingtolerances and quality assurance, andthe encapsulation process, including thehandling, sealing and inspection of can-isters and their transportation to the fi-nal disposal hole. The design docu-ments define the design bases for thecanister, demonstrate the fulfilment ofthe design requirements and assess theresults of design analyses.

The canister structure consists ofa cylindrical massive insert made ofnodular cast iron and a 50-mm-thickcopper canister. Three versions of thecanister have been designed, one foreach reactor type operated in Finland.The fuel assemblies are placed in thecanister in one piece, including anyflow channels belonging to them. Thedifferent versions of the canister mayhold a maximum of 12 BWR fuel as-semblies, 12 VVER 440 fuel assem-blies or 4 EPR assemblies. Each canis-

(ECORAD) held in France in the autumnwith a joint lecture on the developmentof soil ecosystems. The main theme ofthe conference was radiation protectionof the environment.

17

Canister manufacturingtechnology

ter will contain 1.4 to 2.2 tonnes ofuranium, depending on the fuel proper-ties. The external diameter of the can-ister is 1.05 m in all variations, but thetotal lengths are 3.6 m for the VVER440 fuel assembly, 4.8 m for the BWRassembly and 5.2 m for the EPR assem-bly. The total weights are 18.6, 24.3 and29.1 tonnes, respectively.

Both the insert and the copper can-ister can be manufactured using an in-tegrated bottom. With regard to thecopper canister, another alternative isa tube manufactured by extrusion orforging, with welded lids at both ends.

There should be a high probabilitythat the canister will maintain its integ-rity for some 100 000 years. In addi-tion to the good tightness and corro-sion resistance, the good and long-last-ing integrity requires sufficient me-chanical strength, which has been veri-fied by the analyses described in thedesign documents. The load hypothesesof the analyses include the hydrostaticpressure of groundwater, the even anduneven swelling pressure of bentonite,the thermal effects produced by thedecay heat of spent fuel, and the addi-tional hydrostatic pressure caused by a3-km-thick glacier. The permissiblestresses and elongations have been de-termined in such a manner that reason-able safety factors are achieved in allthe design-basis load cases.

The documents give the mechani-cal design calculations for all the threecanister variations. The mechanicalstrength of the canister is excellenteven in cases of uneven or bending loadcaused by swelling of the bentonite andthe load resulting from rock movementsor a 3-km-thick glacier. Calculationsshow that the compression load causedby an external pressure is no less than100 MPa.

The canister has been designed insuch a way that it reduces the radiationon the canister surface to so low a levelthat the radiation does not unreasonablyhamper the handling and transportationof the canister and that the radiationdoes not cause significant radiolysis inthe groundwater. Furthermore, the can-

ister insert has been designed to keepthe fuel assemblies in the subcriticalgeometry even in such a case that theempty space inside the canister wouldbe filled with water and, with respectto OL1–2 and LO1–2, the fuel may beunused or the fuel may exceed a cer-tain burn-up limit owing to the largerassembly of the OL3 plant.

The mechanical strength of the can-ister was determined experimentally bymanufacturing a 700-mm-long testsample from a partly failed insert. Themock-up was surrounded by a 50-mm-thick copper canister and bolted lids. Apressure test was carried out with anisostatic press in a pressure vessel, rais-ing the pressure in stages. At a pressureof about 100 MPa, a plastic deflectionof about 5 mm was produced in the testsample wall. The test was continued toa pressure of 130 MPa, when a plasticdeflection of about 20 mm was discov-ered in the thinnest point of the wall.Further investigations showed that thesquare hollow sections of the insert hadbuckled and detached from the cast in-sert, but no new failures occurred in thecast insert.

The acceptance criteria for canis-ter manufacturing technology were con-sidered jointly with SKB, but the prepa-ration of a final proposal was furtherpostponed.

With regard to canister manufacturingtechnology, one of the principal devel-opment subjects continued to be themanufacture of the cylindrical part ofthe copper canister from one piece withseveral optional manufacturing meth-ods. Manufacturing methods were de-veloped both under the TEKES productdevelopment project of Posiva andOutokumpu Poricopper, and as co-op-eration projects with SKB. The TEKESproduct development project finishedat the end of November 2004 and in thefuture the manufacturing methods willbe developed as Posiva-SKB joint

projects with the component manufac-turers.

Development work on the coppercanister material continued jointly withOutokumpu Poricopper by casting atotal of ten billets in three cast series.The beginning of the billet casting pro-cess was developed to reduce the cen-tral cracking, and the lifting capacity ofthe foundry was increased and as a re-sult it was possible to cast billets ofrecord weight, even 16.6 tonnes. Ow-ing to this, an increasingly long piececan be removed from the base of thebillet in order to minimise casting de-fects. Of the cast billets, one billet waschosen for examination by machiningit axially to the very centre and by con-ducting a liquid penetrant test at inter-vals of 20 mm to discover any castingdefects. No defects were discovered bythe depth of the first 350 mm, but there-after a centre crack was found in thelower end of the casting. Samples weretaken from the billet for analyses of thechemical composition and metallo-graphic examinations.

Two copper canisters with an inte-grated bottom were manufacturedjointly with SKB with the “pierce anddraw” method at the tube factory ofVallourec & Mannesmann Tubes in Ger-many. The method development fo-cused on hot-forming the bottom inorder to achieve a grain size of less than360 mm throughout the bottom, sincein other respects the canisters have al-ready fulfilled the technical require-ments set for them. In accordance withthe plans of the research team set upby Vallourec & Mannesmann, the man-drel and the counterpart of the lastphase of the hot-forming process weremodified, but the grain structure of thebottom hot-formed with them contin-ued to be uneven and the grain sizeslightly too large. On the basis of theseresults, the research team designed newtools once again. The grain size of thewall of the canister manufactured by theprocess was slightly more uneven thanin the canisters examined to date. In thebottom, areas with different deforma-tion grades could be detected; the grain

18

Canister sealing andinspection technology

size requirement was achieved in someof them, but not in others. In terms ofthe dimensions, the canister met the re-quirements.

Forging tests of the copper canis-ter continued under a joint project ofPosiva and SKB. To achieve an evenform and an appropriate inner diame-ter of the tube, a new pair of tools wasordered for use in the last phase of theforging process. A new tube of fulllength was forged using the new tools,but the inner diameter again became toolarge. Furthermore, cracks with a lengthof even 200 mm were formed at oneend of the tube during the hot-forming;studies of their reasons began. The tem-perature of the tube to be hot-formedlowered considerably in the last phaseof the hot-forming, whose effect wasexamined at raised temperatures bymeans of tensile and compression testscarried out with Gleeble equipment atthe University of Oulu. In addition,Kungliga Tekniska Högskolan (KTH) inStockholm numerically modelled theflow of material during the forging pro-cess to find the optimal hot-formingmethod.

Within the joint project of Posivaand SKB, four new copper tubes with awall thickness of 50 mm were extrud-ed at Wyman-Gordon in Scotland. Theresults of the extrusion process werefairly good, and consequently no chang-es were made in the process, since theobjective of the development work wasto demonstrate the repeatability of theprocess while maintaining uniformquality. Preliminary results show thatthe extruded tubes fulfilled the require-ments set for them, except for slightdeviation in straightness.

A casting test of the canister insertmade of nodular cast iron was carriedout at Metso Paper Oy’s RautpohjaFoundry. The casting test was again de-signed jointly with SKB, which contin-ued similar casting tests at three found-ries in Sweden. The targets and qualityrequirements of the tests were consis-tent, such as to improve the toughnessand tensile properties. The insert wascast with an integrated bottom and thescrews that fix the cassette (formingthe channels for the fuel assemblies)to the mould were strengthened to pre-vent the cassette from moving duringcasting. The insert fulfilled the require-

ments for the main dimensions and thestraightness, concentricity and size ofthe holes, but the mechanical proper-ties of the casting in the upper part ofthe insert remained clearly below therequirements. Metallographic examina-tions show that the reason for this isthe slag entrapped in the insert duringsolidification and the incomplete nod-ulising of the graphite.

A summary report was drawn up onthe canister manufacturing costs withthe different manufacturing methodsand routes. The cost calculations arebased on current prices that are estimat-ed for production in series, however.The manufacturing costs of a BWR can-ister manufactured with the “pierce anddraw” method and with an integratedbottom are EUR 135 000. The manu-facturing costs of an extruded canisterare about 6% higher and those of aforged canister about 6% lower. Thecosts of a VVER 440 canister are about10% cheaper, but it is very difficult toassess the costs of EPR canisters, sincetheir manufacture will extend so farinto the future.

Test programmes and developmentwork on the high-vacuum electronbeam welding (EBW) method intendedfor sealing the copper lid of the canis-ter were concentrated to be conductedwithin the scope of the co-operationagreement signed between Patria Avia-tion and Posiva. The electron beamwelding equipment employed by Patria,located at Linnavuori in Nokia, wasmodified to be suitable for the weldingof thick copper; for instance, the weld-ing power of the equipment was raisedto 50 kW and the vacuum equipmentwas replaced. As early as in the start-up phase of the welding equipment itwas possible to implement the first setof the welding test programme bymeans of plate tests. The final target ofthe programme is to verify the weldingparameters suitable for sealing the cop-per lid. During the latter part of the year,two more series of plates were weldedto determine the optimal welding pa-rameters, for instance, the focus of theelectron beam, the weld gap, the begin-

ning, the ending, the overlapping weldand the welding speed. Moreover, tem-peratures were measured at differentpoints of the plate during welding. Inplanning the tests, statistical methods,such as the Taguchi and response sur-face methods, were used to ensure thesystematics and to minimise the num-ber of tests. The methods used to ex-amine the plate test welds included ra-diography and acoustic microscope(SAM) and metallography. The weldingtests of copper lids begin immediatelyin 2005 and, from now on, plans havebeen made to carry out six series ofwelding tests a year.

The heat transfer in a copper plateduring electron beam welding was mod-elled at Tampere University of Technol-ogy. The purpose of the work was todetermine the effect of the size andform of a welding test sample on itstemperature, with a view to establish-ing whether the plate tests and the fu-ture tests on short canister tubes cor-respond to the welding of the lid. Tem-peratures measured from the test sam-ples and those to be measured later areused to support the modelling. Thework is being continued in 2005, in-cluding modelling the heat transfer inshort copper tubes and measuring thetemperatures during the welding of lidsin support of the modelling results.

Posiva was involved in SKB’s de-velopment work on the low-vacuumelectron beam welding method and thefriction stir welding (FSW) method. Tosupport this work, studies were con-ducted, for instance, to establish theproperties of material welded with theFSW method and equipment suitable forboth the EBW and the FSW methodswas designed to measure the tempera-ture of the material and/or the tool dur-ing welding.

The TEKES/EU project imple-mented by the Technical Research Cen-tre of Finland (VTT) and Helsinki Uni-versity of Technology with a view toincreasing domestic expertise and re-sources in the field of FSW technolo-gy is nearing completion. The targetsset for the project have been achieved,since within the project Finland hasacquired one FSW licence for Helsin-ki University of Technology and one setof production equipment (KTM Tek-niikka, Kankaanpää).

19

A copper billet machined axially to the very centre to find any casting defects.

Development engineer Timo Salonen behind the welded plate samples.

20

Design of theencapsulation plant

Fuel transportation

Nuclear materialsafeguards

Basic data for design of therepository and theconstruction methods

A domestic expert and equipmentnetwork of the inspection technologyof copper plates and lids was built. Ne-gotiations were conducted in Finland toplan a qualification procedure, and Po-siva also took part in the developmentprogramme led by SKB aimed to drawup a preliminary proposal for a qualifi-cation plan covering the entire canisterproduction chain.

With regard to designs for the encap-sulation plant, a compilation was madeof the documented encapsulation plantalternatives, and it was supplementedwith the design modifications that hadso far not been documented.

SKB assigned the task of collect-ing the documents required for a con-struction licence to the INKA project.Posiva attended the “Projektgrupp” and“Teknik” meetings of the INKA project,commented on the design documentsand compared SKB’s and Posiva’s de-signs for the encapsulation plant. Thecompared issues included the designbases, costs, designs for the systemsand components, and regulatory guidesand requirements.

A report entitled “Description ofthe above ground facilities of the Olki-luoto final disposal facility” was drawnup as part of the design of the reposi-tory. The report also contains an updat-ed description of the encapsulationplant design.

The design of the docking stationof the fuel-handling chamber at the en-capsulation plant was ordered fromAfore Oy and the work is in the start-up phase.

Material required to support theselection of the encapsulation plant al-ternative to be further developed wasprepared, and Posiva was involved indesigning the extension of TVO’s KPAStore and the interim storage systems.

The cost estimates for the road, rail andsea transportation alternatives of spentfuel were updated.

To be able to later dispose of spent fuelin the ONKALO underground rockcharacterisation facility, which is underconstruction, STUK’s Guides YVL 6.9and YVL 8.5 are being complied within ONKALO. Preparation of a manualfor the nuclear material safeguards inaccordance with Guide YVL 6.9 waslaunched to implement the nuclear ma-terial safeguards. The first draft of themanual will be completed by the end ofMarch 2005 and the manual will bebrought into use during 2005 afterSTUK has approved it.

The basic data for design constitutes,to a great extent, the data required dur-ing the building stage, which is utilisedin the design of ONKALO and the re-pository. Basic data is needed, for in-stance, to design the layout of the re-pository spaces, and to design and im-plement the excavation, reinforcementand grouting work. This package of tasksis divided into the development worklinked with rock excavation and thework that supports design of the actualrepository.

Posiva is involved in SKB’s APSEproject (Äspö Pillar Stability Experi-ment), in which the rock pillar betweentwo full-scale, differently pressuriseddeposition holes is fractured. The forcerequired for the fracturing is producedby geometrically forming the tunnel inthe test area and, thereafter, by heatingthe rock in the test area in such a man-ner that its stress rises high enough interms of the failure. The objective is toverify in full scale the behaviour ofrock described with the aid of modelsand, in particular, to establish the ef-fect of the backfilling support pressureon the failure. Another objective is toacquire practical experience of the

rock breaking and its detection withmeasuring devices with a view to mon-itoring the underground spaces duringexcavation. During 2004, Posiva fin-ished and reported on the 3D model-ling of the test performed with a newtype of linked numerical method, inwhich the formation of microfracturesin the points essential for the test wassimulated with the particle flow code,while the deformations in the surround-ing area were modelled with the moreconventional finite-element method.The modelling simulated the generationand expansion of fractures in fracturedareas. The modelling shows that frag-mental microfracturing is generated inthe fracturing areas first, but at a laterstage the fracturing begins to concen-trate, finally forming single fractures,which in the end lead to weakening andfailure. The experimental part of thetest was carried out in summer 2004,when the rock pillar between the exper-imental full-scale final disposal holeswas fractured. Analysis of the resultsand comparison between the modellingresults and the actual discovered frac-tures began in autumn 2004 and con-tinues to be underway.

Development work on groutingmaterials that generate a low pH (pH≤11) is underway as a co-operationproject of Posiva, SKB and NUMO. Onthe basis of laboratory tests and prelim-inary field tests, the work concentrat-ed on developing a mixture of cementand silica, whose optimisation is beingcontinued in 2005. As part of the de-velopment work, requirements for low-pH grouting cements were assessed andtheir long-term safety and environmen-tal aspects were examined. Some of thealternative materials had to be rejectedowing to potential risks linked withlong-term safety.

To ensure a tight final result at thefinal disposal depth, the objective isalso to develop grouting materialswhose penetrability is better than thatof cement. The studies and field testsconducted in Sweden showed that sili-ca sol was the most promising materialto penetrate into small fractures.

21

Development of the basicconcepts for final disposal

Technical design of therepository

Posiva and SKB are jointly carrying outa long-term project (2002–2007) con-cerning the horizontal disposal conceptof the canister. This basic concept iscalled the KBS-3H concept, to distin-guish it from the concept in which thecanister is placed in the vertical posi-tion (KBS-3V). The installation tech-nique involves a new type of conceptin which the canisters and bentoniteblocks packed into perforated steelcontainers would be installed in about200-m-long horizontal deposition tun-nels. Considerably less rock needs tobe excavated in this concept than in thevertical disposal concept. The work isbeing done in several phases. The ob-jective of the development programmeis to enhance the KBS-3H concept soas to reach the level of the KBS-3Vconcept in technical terms, and to dem-onstrate the drilling of deposition tun-nels and the installation of canisters andbentonite blocks in the long horizontaltunnels.

During 2004, the tender documentsfor the installation equipment of thebentonite/canister package were com-pleted, the invitation for tenders wasconducted, and the further designer andthe future manufacturer of the equip-ment were selected. This activity isbeing carried out as a part of the EU’sESDRED project. Furthermore, theKBS-3H final disposal package was fur-ther designed and dimensioned. Safetystudies conducted in 2004 are dis-cussed above in the chapter concern-ing safety analysis.

In the KBS-3H project, an impor-tant area of design was also developingthe drilling technique for the deposi-tion tunnels. The blind drilling of thefirst 15-m-long pilot hole was per-formed in the autumn of 2004. The pi-lot hole was thereafter enlarged with anew type of technique so as to have adiameter of 1.8 m and to become a hor-izontal KBS-3H deposition tunnel. Thepurpose of the drilling was to demon-

strate the performance of both the pi-lot hole drilling and the enlargementtechnique as well as their further de-velopment needs. Towards the end of2004, an about 70-m-long pilot holewas drilled by the next, longer deposi-tion tunnel. The second pilot hole willbe enlarged to its final size in early2005.

As part of the ESDRED project, thesealing plug of the KBS-3H tunnelbased on shotcreting was developedunder ENRESA’s direction. The plugwill be constructed in the 15-m-longtunnel drilled at Äspö during 2005.

As for studies into the propertiesof buffer bentonite in 2004, Posiva wasmainly involved in international co-op-eration. Some of the bentonite studiesare conducted as part of the technicaldesign work under the KBS-3H project,in which studies into the technical de-signs of bentonite blocks continued in2004 with laboratory tests on differentscales, whose purpose was to techni-cally solve the problems linked with thedevelopment of bentonite in the initialphase of final disposal.

The summary report of the EU’s“Cluster Repository Project - A Basisfor Evaluating and Developing Conceptsof Final Repositories for High-levelRadioactive Waste (CROP)”, whichwas completed in 2004, described thedifferent final disposal concepts andobservations about them.

In 2003, Posiva and SKB jointlylaunched a long-term programme linkedwith backfilling of the repository. De-scriptions of the different backfillingalternatives were drawn up and the mostfeasible methods were selected for fur-ther development in the first phase. Thesecond phase was launched in 2004 withthe objective of providing deeper insightinto the different concepts. The selectedconcepts were a mixture of crushedrock and bentonite and expansive natu-ral clay compacted in situ and the useof precompressed clay blocks. Labo-ratory studies concentrated on the nec-essary compaction power to fulfil therequirements and on the compactionmethods for compaction in situ. With

regard to precompressed blocks, prop-erties of the materials were studied andtests linked with the manufacture andinstallation were carried out. Work onthe second phase is being continued in2005.

It has been planned that EuropeanCa-Mg bentonites can be used for tun-nel backfilling, and Posiva is co-oper-ating with, for instance, the CzechRAWRA to characterise montmorillo-nite-rich clay deposits in the CzechRepublic. Work on the final report ofthe project began at the end of 2004.

The second part of the preliminary de-sign stage of the repository waslaunched in 2004; its objective is toproduce a technical solution that is in-creasingly Olkiluoto-specific. The ref-erence solution of this design, whichis scheduled for completion in 2006,is a final disposal design in accordancewith the KBS-3V concept. The designwork launched in 2004 takes accountof the importance of OL3 for the re-pository and its operations. The plansfor 2004–2006 will include studies onthe extension of the facilities for a larg-er fuel volume and on the applicationof multi-storey concepts to the Olki-luoto bedrock. A two-storey concept isfeasible for both the vertical and thehorizontal disposal concepts. Thermaloptimisation of the dimensioning ofthe repository is also being performed.

In the design period of 2004–2006,studies will also pertain to the step-wise implementation of the repositoryspaces, and the construction, operationand sealing of the repository. The stud-ies will also contain a description ofthe safeguards of nuclear materials, ra-diation protection principles and oper-ation in the event of incidents and acci-dents.

With respect to systems design,basic systems for the ventilation of therepository were assessed in 2004. Thefirst task is to lay down the principles

22

The Äspö Hard RockLaboratory

for the ventilation of ONKALO, whichwill thus provide a basis for the venti-lation system of the repository.

In 2004, the plan for the transportand installation vehicle was further de-veloped to also become suitable fortransport of the canister on the inclinedramp. The vehicle moves on a crawlerbase, whose benefits include a highweight-carrying capacity even on un-even ground, a small fire load and a nar-row turning radius of the vehicle.

SKB and Posiva mostly operated with-in the co-operation framework as inprevious years. In addition to this, sev-eral joint projects were launched orplanned during the year, which are notdirectly included in the co-operationprogramme at Äspö, but in which it willbe possible to utilise the Äspö HardRock Laboratory or ONKALO for mak-ing demonstrations in the future. Thesejoint projects include, for instance,development work on the KBS-3H con-cept, development work on the low-pHcement and the joint project on back-filling technology (further informationon the above-mentioned projects canbe found under, e.g., “Final disposaltechnology”).

At Olkiluoto, Posiva is mainly con-centrating on research into the bedrockconditions and into the assessment ofsite-specific or site-dependent factors.General development of the rock con-struction methods for the repositorycan also be implemented in ONKALO.At Äspö, Posiva is performing the gen-eral verification and demonstration ofoperations linked with engineered bar-riers and repository technology. Fieldtests that provide a basis for the assess-ment of long-term safety are carriedout at Äspö linked with the performanceof the bedrock as a natural barrier.

The investigations to be carried outat the Äspö Hard Rock Laboratory with-in the framework of international co-operation have been grouped as fol-lows:

– investigations linked withtechnology;

– investigations linked withgeosciences;

– investigations linked withnatural barriers;

– investigations linked withoperations of the Äspö HardRock Laboratory.

Posiva is involved in the “PrototypeRepository” project, which is imple-mented at SKB’s Äspö Hard Rock Lab-oratory. The project was accepted intothe EU’s framework programme for2000-2003. The KBS-3 final disposalconcept is being tested and demonstrat-ed in the project by constructing a full-scale long-term test for a sealed finaldisposal tunnel. During 2001, canistermodels fitted with heaters and surround-ed by compacted bentonite were placedin four full-scale deposition holes. Inaddition, the tunnel was equipped withinstrumentation, and a sampling systemwas also installed. Finally, the tunnelwas filled with a mixture of crushedstone and bentonite, and closed by asolid concrete structure. In 2003, can-isters were installed in the tunnel sec-tion of the second phase in two deposi-tion holes lined with bentonite, theopen tunnel section was filled with amixture of crushed stone and bentonite,and it was fitted with a concrete plug.The actual test began in the autumn of2004.

Posiva is involved in the LOT test(Long-Term Test of Buffer Material) tobe carried out at the Äspö Hard RockLaboratory. The test pertains tovalidating the hypotheses and models oflong-term processes occurring in thebuffer material, and the closely linkedprocesses concerning microbiology,the migration of radionuclides, coppercorrosion and the migration of gas. Thetests are performed at a depth of about500 m, in boreholes drilled in thetunnel bottom; the boreholes have adiameter of 30 cm and a depth of 4 m.The tests to be performed in fiveboreholes were begun in 1999, and theyhave been planned to last for 1, 5 and20 years.

Posiva is taking part in the four-year international working group orga-nised by the Äspö Hard Rock Labora-tory, which was launched in 2004,whose task is to model the behaviourof the engineered barrier system (EBS)under the final disposal conditions.Posiva is involved in the subproject thatmodels the thermohydromechanical

(THM) behaviour of the processes oc-curring in the buffer bentonite and tun-nel backfilling material as well as in thenear-field of the bedrock during satu-ration. In 2004, the modelling per-tained, for example, to the free expan-sion of bentonite. In 2005, the simula-tion will concern the THM(C) behav-iour of the EBS in the KBS-3V andKBS-3H concepts, considering the ef-fects produced by installation holes.The modelling work to be conducted islinked with the EU project dealing withprocesses in the near-field (NF-PRO)and with the master’s thesis entitled‘Thermo-Hydro-Mechanical Analysesof KBS-3V Deposition Hole’ (A. Lem-pinen) to be published in 2005.

Posiva and SKB jointly launchedthe first phase of the project linked withbackfilling of the repository. The ob-jectives of the first phase were to de-scribe the optional backfilling methodsthat had been determined together andto assess their performance from theviewpoint of the requirements, and toselect the most feasible methods forfurther development and to assess thevolume of the required research anddevelopment work before commission-ing of the repository. The work of thesecond phase launched in 2004 consistsof studying the materials of the select-ed concepts as well as designing andtesting the manufacturing and installa-tion technology on a small scale.

Posiva was involved in SKB’s APSEproject (Äspö Pillar Stability Experi-ment), whose purpose is to carry out alarge-scale failure test on the pillarbetween two final disposal holes.

The objectives of the work are:– to test the opportunities for

predicting the strength be-haviour of crystalline, hard rockon the tunnel scale and in an in-tense stress field using numeri-cal modelling programsFLAC3D and PFC2D. Inaddition, the linked programFLAC2D/PFC2D was applied asa completely new one.

– to acquire practical experiencein the monitoring of rockdamage using, for instance,acoustic emission (AE)measurements and to comparethe measured responses withthe modelled results. AE is a

23

DESIGN OF THEUNDERGROUNDCHARACTERISATIONFACILITY

Construction of theunderground rockcharacterisation facility

highly feasible and interestingmethod to use during construc-tion of ONKALO as well.

– to demonstrate and furtherimprove opportunities tocontrol growth of the EDZzone. The test will examine theeffect of the pressure prevailingin one hole on the propagationof fractures.

During 2003, Posiva took part inthe practical implementation and designof the failure test. In addition, Posivawas involved in the excavation projectof the APSE tunnel, which also investi-gated issues linked with the feasibilityfor grouting and the effect of blastingdiagrams on the excavation result. Thefailure test was modelled by perform-ing thermomechanical analyses withboth the FLAC3D program and thelinked FLAC2D/PFC2D program. Thepreliminary FLAC3D analyses werereported in SKB’s IPR series of reportspublished in 2003. A report on the de-tailed analyses was completed in early2004. The actual failure test waslaunched at the end of 2003 with exca-vation of the first final disposal hole.The second final disposal hole was ex-cavated in the beginning of 2004 andthe actual failure test was carried outin summer after the heating phase.

The objective of the boreholecleaning and sealing project is to de-velop a concept for the sealing of in-vestigation boreholes drilled near therepository. The sealing prevents the in-vestigation boreholes from functioningas potential migration paths of ground-water in the bedrock, which is neces-sary for long-term safety of the repos-itory. In addition to issues related to theactual plug, the project also includesthe cleaning and stabilisation of the in-vestigation boreholes.

The project began with a feasibili-ty study in 2002. Phase 2 was launchedin 2003 and it finished at the end of2004. Phase 3 is scheduled for 2005–2006. The objectives of the secondphase of the project were a) to developa method that would possibly fulfil therequirements set for the sealing, and b)to make a recommendation for the full-scale tests to be conducted in phase 3.Posiva was involved in the work ofphase 2 by drawing up a report on thecleaning of the investigation boreholes,

which was used as a background reportfor the report describing the sealingconcept, which SKB published at theend of 2004. Posiva also took part inthe operation of the project group in2004.

Before a decision to construct a repos-itory is taken, supplementary bedrockinvestigations will be carried out atOlkiluoto for the implementation de-sign of the facilities. An undergroundrock characterisation facility, known asONKALO, will be constructed for theinvestigations and design. Excavation ofthe open cut began in summer and ex-cavation of the tunnel in autumn 2004.

ONKALO should be constructed toallow underground investigations forsite confirmation without jeopardisinglong-term safety of the repository site.In addition, it should be possible to lat-er link ONKALO by incorporating itinto the repository.

In the preliminary design stage ofONKALO in 2001, the alternatives thatincluded at least two separate accessroutes were considered feasible interms of operational safety. In the out-line planning stage in 2002, two alter-native draft designs were drawn up onthe basis of the preliminary design: theshaft alternative and the access tunnelalternative. After the evaluation, theaccess tunnel alternative was chosen asthe basis for the main drawings stageof ONKALO owing to, for instance, thehigher flexibility, the greater feasibili-ty for investigations and the betterworking conditions. The main drawingsstage ended with submission of the ap-plication for a building permit to themunicipality of Eurajoki in May 2003.The implementation plan material andthe supply documents were completedfor the invitation for tenders for thefirst tunnel contract towards the end of2003.

The first tunnel contract was signedin the spring of 2004 and it covers theexcavation and structures of the access

tunnel (to level –417 m) near the maincharacterisation level and raise boringof the shaft to level –287 m. Design ofthe building stage began at the sametime. Designs for the systems duringconstruction related, for instance, toventilation and pumping, were updatedwith the contractor. Designs for theopen cut were supplemented on the ba-sis of the observations made duringexcavation and the designs for the tech-nical building were finished to be readyfor submission of the application for abuilding permit. Layout of the accesstunnel was fine-tuned on the basis ofthe updating of the bedrock model. Anadditional connection was already de-signed to level –11 m to simplify theconstruction work and the ventilationsystem.

In summer 2004, a new research hallof 380 m2 was put into use in theONKALO area. The research hall in-cludes an investigation room for drillcore samples, where the rock samplescan be spread over a distance of sever-al hundred metres and the rock materi-al of the borehole can be analysed overthe full borehole length. The research-ers have worked intensively in the hall,which has considerably enhanced andaccelerated the analysis of drill cores.In the research hall there is also asound-proof sawing room for the saw-ing of samples. The occurrence of min-erals in drill core samples, for instance,is investigated in the microscopy room.The area of the storage building is 250square metres and rock samples, amongother things, will be stored there.

The field laboratory of the researchhall, which was completed during theyear under review, facilitated the pre-treatment and preparation of water sam-ples before sending them to other lab-oratories, although the laboratory isalso fitted with equipment for simpleanalyses.

The preparations above ground atthe ONKALO site began in June 2004.The first work consisted of erecting thesite huts and digging land masses fromthe entrance to ONKALO. The initia-

24

Layout of ONKALO was fine-tunedand an additional connection wasalready designed from level –11 m.The scope of the first tunnel contractis shown in red.

tion blast for ONKALO was set off on29 June. The Minister of Social Affairsand Health, Sinikka Mönkäre, honouredthe occasion with her presence, andrepresentatives of the media were alsopresent.

The excavation work began withexcavation of the open cut, which wascompleted on 6 September 2004. Theexcavation of the tunnel began with thebolting and grouting of the tunnel por-tal. The actual excavation of the tunnelbegan on 22 September 2004. The firstrounds were blasted in many stages andcarefully. The purpose of careful exca-vation was to limit the loosening of rockto as little as possible.

One near-miss case and one acci-dent occurred at the site in 2004. Inboth cases, it was a question of a looseblock, which in the near-miss case fellclose to a geologist and in the accidentcase on the helmet. The latter resultedin a four-day sick leave. Particular at-tention has been focused on occupa-tional safety issues at our unique site.Both the purchaser and the contractorwork in the spirit of “zero accidents”.

Of the area work that supports thetunnel excavation, the work included inthe first and second phases of the con-tract was completed. The work consist-ed, for instance, of the research hall,the drilling and discharge water sys-tems, the settling basin and the pump

building. The site fence, area lightingand the technical building will be com-pleted in the last, i.e. the third, phase.

The area work included in the con-tract agreed to be conducted by Kallio-rakennus Oy is still underway. The workis planned to be completed in the sum-mer of 2005. The work consists, forexample, of building the sustainingwalls of the tunnel.

The excavation work progressedmore slowly than expected in the orig-inal schedule. The speed of tunnellingwill increase owing to new equipmentand the decreasing volumes of grout-ing material. The tunnel progressed atabout 15 to 20 m a week.

Bedrock investigations were car-ried out as part of the excavation work.They support both the design and con-struction of ONKALO and the charac-terisation of bedrock in the final dis-posal area. The investigations includegeological mapping and the drilling ofprobe and pilot boreholes. After everyfourth excavation round (at intervals ofabout 20 metres), four about 26-m-longprobe boreholes were drilled, and flowand water consumption measurementswere carried out in them. The resultswill be used to determine the need for

pre-grouting in the tunnel. The ROC-MA equipment, which is connected tothe new DATA drilling jumbo, will bebrought into operation in the beginningof 2005. The equipment will help as-sess variations occurring in the bedrockproperties. This will supplement othermeasurements conducted in the probeboreholes.

In the early stages of the tunnel-ling, the rock has been grouted usingsome 100,000 kg of fine cement. Theconsumption of grout per groutinground has reduced to half the consump-tion during the first five groutingrounds. This means that the rock is nowtighter than previously. The groutinghas succeeded well, since the amountof water seeping into the tunnel wasmeasured to be 0.15 litres/min/100 tun-nel -metres.

Parameters by the end of the year:– Total length of the tunnel 157 m– Excavation volume some 6,250

m3

– Consumption of the grout106,000 kg.

25

MANAGEMENT OF OPERATING WASTE

OLKILUOTOPOWER PLANT

Principles and schedule

Current status of storageand final disposal

Operating waste produced at the Olkiluoto Power Plant

Total volume of waste In the VLJ RepositoryKAJ Silo MAJ Silo Total

(pcs) (m3) (pcs) (pcs) (m3)Bituminised waste 7,097 1,420 6,830 1,366Other operating waste– in drums 6,338 1,112 6,077 1,060– in steel containers 455 632 5 450 632– in concrete boxes 223 1,159 19 189 1,082– unpacked 360

Total 4,683 4,140

In addition to high-level spent fuel, theOlkiluoto and Loviisa Power Plantsproduce intermediate- and low-levelnuclear waste, comprising used reactorinternals (e.g., control rods and coreinstruments) and plant operating waste(e.g., ion-exchange resins and miscel-laneous maintenance waste). The man-agement of used reactor internals isdiscussed in the section entitled “De-commissioning investigations”. Themanagement of operating waste is dis-cussed below.

Most of the operating waste is pack-aged immediately for handling, storageand final disposal. The intermediate-level ion-exchange resins used to cleanthe process water are solidified intobitumen, and the mixture is cast intosteel drums. Some of the low-levelwaste (compressible miscellaneousmaintenance waste) is compacted intothe steel drums with a hydraulic press,and some (metal scrap and filter rods)is packed as such into steel containers,concrete boxes and steel drums. Drums

containing compressible waste are fur-ther compacted so that the final heightof the drums is approximately one halfof the original (the diameter, however,does not change). Metal scrap can alsobe compacted before packaging. Withthe aid of the metal shredder acquiredin autumn 2004 it is possible to fillempty space remaining in the concreteboxes that are taken to the repositorywith shredded metal and thus the volu-metric efficiency of the packaged metalwaste is increased. Miscellaneous liq-uid waste and sludge are solidified bymixing the waste with a binding agentin a drum that also serves to contain thesolidified mixture.

Operating waste is stored tempo-rarily at the plant units, in the storagefacility for intermediate-level waste(KAJ Store), in the storage facility forlow-level waste (MAJ Store), in theenclosed storage area and, to a minorextent, in the KPA Store, at the Olkilu-oto plant site. Intermediate- and low-level waste produced during powerplant operation is disposed of in thepresent waste silos of the repositoryfor operating waste (VLJ Repository).Very low-level waste is exempted fromregulatory control and is either trans-ported to the dump at the Olkiluotoplant site or handed over, for example,to be processed for reuse.

The table below shows the current sta-tus of storage and final disposal at theend of 2004. The waste has been packedinto drums (200 litres each, or about100 litres in compacted form), steelcontainers (1.3 or 1.4 m3 each) andconcrete boxes (net 5.2 m3 each). Inaddition, Studsvik Energiteknik AB heldfive drums of low-level ash generatedin an incineration test in their storagefacility in Studsvik, Sweden. If neces-sary, the drums and containers arestored in the storage facilities of theplant units and the KAJ Store beforefinal disposal in the VLJ Repository.Before transfer to the VLJ Repository,the drums and steel containers wereplaced in large (net 5.2 m3 each) orsmall (net 3.9 m3 each) concrete box-es, the large boxes housing 16 drumsor 7 drums and 2 steel containers, andthe small boxes 12 drums. Correspond-ingly, the concrete boxes will housetwice as many compacted drums.

Bulky contaminated metal compo-nents are stored in the KAJ Store andthe adjoining enclosed storage area. Inaddition, unpacked operating wastes,such as used ventilation filters and non-bituminised resins, are stored at the

26

Studies on operating waste

plant units, and waste oil in the KPAStore. Some of the metal scrap will bedisposed of as such in the concreteboxes used in the VLJ Repository.Some of the unpacked waste will laterbe exempt from regulatory control andwill either be reused or transported toa dump. For example, very low-levelwaste oil may be exempt and reused. Atthe end of 2004, the amount of suchwaste oil was 18 m3.

The waste storage facilities of thepower plant units can house some1,000 drums each. The MAJ Storemainly houses only very low-level main-tenance waste bags and scrap, whichwill be exempt from regulatory control.The KAJ Store can house drums, con-tainers and bulky, contaminated metalcomponents, the total volume of whichcomprises some 6,000 drums.

The capacity of the intermediate-level waste silo in the VLJ Repositoryis 17,360 drums (200 litres each) andthat of the low-level waste silo 24,800drums, i.e. about 8,400 m3 of operat-ing waste packed in drums, or the equi-valent of the waste accumulated during40 years of operation of the two powerplant units at Olkiluoto. Additional re-pository facilities can be built in thesame bedrock area, if necessary.

Radioactive wastes from small pro-ducers are stored in the VLJ Reposito-ry at Olkiluoto. The Radiation and Nu-clear Safety Authority (STUK) has sofar been in charge of these wastes,which consist of radioactive materialused mainly in hospitals, research in-stitutes and industrial plants. By the endof 2004, 45 m3 of this waste had accu-mulated in the VLJ Repository.

A large-scale test of the microbiologi-cal degradation of low-level mainte-nance waste is being conducted in theconstruction tunnel of the VLJ Repos-itory. The project was launched as partof the PROGRESS project of the EU’snuclear fission safety programme in1997. These studies are conducted todetermine more exact estimates of thevolume of gases generated by mainte-nance waste, and in order to gain a bet-ter understanding of the entire degra-dation process under the conditions thatcorrespond to the situation after thesealing of the VLJ Repository. Thisproject also involves monitoring themigration of activity from the wastedrums to the surrounding water.

In the gas generation test, the pHin the tank was roughly unchanged at thetank bottom and slightly lowered on thelid level of the drums. It seems that theamount of cultivable microbes has in-creased during the year under review,both in drums that contain biodegrad-able waste and in those containing non-biodegradable waste. Visual examina-tion showed that the waste materials hadmostly remained unchanged. The cor-rosion of carbon steel plate is consid-erably faster in a drum that containsbiodegradable waste than in the otherdrums of the test.

In the tank, the dominating microbespecies have changed during the test,and the populations on the surface andbottom levels differ. On the basis of thereference data on the result sequenc-es, it can be assumed that many of themicrobes occurring in the tank water donot represent known species. In 2004,VTT Biotechnology made microbio-logical assays of two water samples andcarried out the microbiological analy-sis of the solids in five canisters.

TVO and BNFL made the follow-ing agreement concerning the model-ling of the gas generation test: TVOgets the results of the modelling for itsuse, while BNFL gets the results of the

27

Studies during theoperating period of theVLJ Repository

LOVIISA POWER PLANT

Principles and schedule

Current status of storage

test for its use. The agreement contin-ued to be under examination at BNFL.

The calcium and magnesium con-tents of the test tank increased slight-ly. In 2004, the iron content was nearlytriple compared with the results of2003. The ammonium content contin-ued to rise. Of the gases, methane is themain gas. In September 2004, the cu-mulative total gas amount was 5,250 l.The monthly production was about 50to 70 l, which continues to be clearlybelow the value used in the safetyanalysis.

Operation-time monitoring of the VLJRepository continued in 2004 in accor-dance with the research and monitor-ing programme drawn up previously.Under the programme, extensive mea-surements are carried out at intervalsof three years and additional measure-ments are taken, if necessary. The lasttime the extensive measurement pro-gramme was implemented was in 2003.The water chemistry of groundwaterstation PVA2 is monitored annually.The water quality at the groundwaterstations of the VLJ Repository at Olki-luoto has been monitored since the lat-ter part of the 1980s.

In spring 1993, ten test bolts wereinstalled in the research tunnel of theVLJ Repository at Olkiluoto to estab-lish the corrosion rate of the bedrockbolts. The objective of the test is toobtain information on the corrosionresistance of galvanised reinforcementbolts in the bedrock under the condi-tions of the VLJ Repository at Olkilu-oto, with the hypothesis that the cementmortar protecting the bedrock boltscompletely loses its protective prop-erty. The first test bolt was removed bycore drilling in 1996 and the secondbolt in 2004.

Since the bedrock bolts had re-mained unchanged, support tests werelaunched in 1998 to study the corro-sion behaviour of galvanised steel in theborehole of the bedrock bolt removedfrom the research tunnel (“Bolt 7”).Thin galvanised steel plates and con-

crete cylinders were installed in theborehole, thus seeking to regulate thegroundwater pH so as to make it morealkaline, and thereby simulating the ac-tual environment of the reinforcementbolts in the operating conditions. Sincethe water chemistry in the above bore-hole has not been stable and the corro-sion rate of the samples was contraryto expectations, a decision was takento transfer the samples to the boreholelocated in the construction tunnel(VLJ-KR9). The water chemistry andconditions of the new disposal holewere studied in spring 2002, and 18new zinc-coated steel plates and 16 zincplates were installed in the boreholewith the concrete cylinders in Septem-ber 2002. The water chemistry of thedisposal hole is monitored annually.After one test-year, no corrosion couldbe detected in the zinc-coated steelplate samples. The corrosion of zincplates (three years) had not progressedin the new test hole. In 2004, no sam-ples were collected, but the zinc-coat-ed steel plates and zinc plates were ex-amined visually.

Intermediate- and low-level operatingwaste is conditioned and stored at theplant site. Spent ion-exchange resinsand evaporator concentrates are storedtemporarily without solidification intanks in the liquid waste storage facili-ty.

Compilation of the preliminarysafety analysis report (PSAR) of a ce-mentation-based solidification plantbegan towards the end of 1997. The pre-liminary safety analysis report was sub-mitted to STUK for approval in the be-ginning of 2000 and it was approved inthe spring of 2001. Preliminary designof the solidification plant began in2002 and the implementation designtowards the end of 2003. The construc-tion was launched in early 2004. Thesolidification plant is scheduled forcompletion at the end of 2006.

Fortum has invested heavily in thedevelopment of new waste-treatmentmethods. These efforts have resulted ina waste-treatment method that sepa-

rates caesium from the evaporator con-centrate and reduces the waste to a verysmall volume. The evaporator concen-trate is then so clean that a larger vol-ume than previously can be exempt fromregulatory control without increasingthe annual activity release.

Dry maintenance waste from pow-er plant maintenance and repair work ispacked in steel drums of 200 litreseach. Compressible waste is compact-ed into drums with a hydraulic press,thereby reducing the volume by a fac-tor of 3 to 4.

Intermediate- and low-level oper-ating waste from the Loviisa PowerPlant is disposed of in an undergroundrepository built in the bedrock at thepower plant site. The repository was putinto operation as an interim store in thespring of 1997. The repository receivedan operating licence in the spring of1998, and the repository has been usedfor the final disposal of maintenancewaste since the summer of 1999.

In 2004, a study was conducted at theLoviisa Power Plant concerning im-provement of the treatment and storagefacilities for operating waste. A memo-randum on the current status of wastetreatment and storage and on the futureplans was submitted to STUK in De-cember 2004. As far as the most im-portant changes in the treatment andstorage of operating waste are con-cerned, the following facts can be stat-ed:

– The wastes produced in 1995–2003 and now exempted fromregulatory control were takento the Keltakangas waste centreof Kymenlaakson Jäte Oy.

– The decontaminated metalwaste and other metal wastefree from radioactivity arestored temporarily in theformer sandblasting hall toawait exemption from regulato-ry control. Space is thus clearedin the metal scrap store of LO1for maintenance waste drumsand at the waste-packing plant.It will be possible to performthe soaking-solidification ofsolvent wastes in spring 2005and the rooms below waste-

28

Operating waste produced at the Loviisa Power Plant

Total volume Share of the Activityof waste storage capacity

At the plant/in the In thestorage buildings repository

(m3) (m3) (%) (GBq)

Spent ion-exchange resins 445 50 13,892Evaporator concentrates 614 58 390Maintenance waste 332 1,234 487

Total 1,391 1,234 14,769

The final disposal facilitypacking plant 1A0343 willbecome free for use as interimstores for more active main-tenance waste drums, oils andsolvents. The sorting table andsack monitor for wastes cannow be put into use at thewaste-packing plant. STUKapproved the plan in December2004.

– About 9 m3 of miscellaneouslow-level solvent wastes,mainly motor washing agent,have accumulated duringoperation of the power plant.The soaking-solidification ofsolvent wastes will be per-formed in October 2005 using aspecial solidifying agent in200-litre drums in a similarmanner as has been done at theOlkiluoto Power Plant foryears. STUK approved the planin August 2004.

– A bridge crane was installed inmetal scrap store 1A0901 ofLO1 in 2004.

– Implementation design of thegate monitor, i.e. the activityand dose rate measuringequipment of vehicles enteringand leaving the power plant,began in autumn 2004.

– Construction and installationwork of the second stage of therepository is being carried outin 2004–2006. Completion ofthe previously excavatedmaintenance waste room 2(HJT2) began in November2004, and this room will be putinto operation as a final

disposal facility in May 2005 atthe latest. Construction andinstallation work of thepreviously excavated finaldisposal hall for solidifiedwaste (KJT) will begin inMarch 2005 and it will becompleted towards the end of2006, simultaneously withthe seepage water poolbuilt in the repository. Thedisposal hall for solidifiedwaste will be needed for thefinal disposal of wastepackages completed at thesolidification plant from theend of 2006 onwards.

– Construction of the solidifi-cation plant for active wastebegan in early 2004 and itwill be completed on scheduleat the end of 2006.

– The project aimed to renovate/construct the treatment andstorage facilities for low-levelmaintenance waste waslaunched in December 2004. Abasic design will be submittedto STUK for approval aftercompletion of the preliminarydesign. The design will alsoinclude replacement of thegamma spectroscopicmeasuring equipment for wastedrums.

The table below shows the currentstatus of storage and final disposal atthe end of 2004.

Intermediate- and low-level operatingwaste produced at the Loviisa PowerPlant will be disposed of in a reposito-ry constructed in the bedrock ofHästholmen Island. Fortum has beenconducting studies on the suitability ofthe bedrock in the power plant area forthe final disposal of waste since theearly 1980s. A preliminary safety anal-ysis report on the final disposal facili-ty was completed in 1986. In 1988, theRadiation and Nuclear Safety Authori-ty (STUK) approved the safety analysisreport and granted permission, in accor-dance with the power plant operatinglicence, for the construction of a re-pository. Preparatory construction ac-tivities began in 1992, and constructionstarted in February 1993.

Excavation work begun in spring1993 was completed on schedule inDecember 1995. Construction and in-stallation work was started in Novem-ber 1995. The installation work wascompleted on schedule in late 1996, atwhich time an application for the oper-ating licence of the repository was alsosubmitted. The repository was put intooperation as an interim store in spring1997 and as a final disposal facility insummer 1999.

The final repository comprises atransport tunnel of about 1,100 metresin length, tunnel and hall spaces built ata depth of about 110 metres, and stairand ventilation shafts. The constructionof the repository is implemented intwo stages. During the first construc-tion stage, all repository spaces andaccess routes were excavated. These

29

The caesium separationfacility

Studies on solidificationmethods

Studies during theoperating period of thefinal disposal facility

included two final disposal tunnels formaintenance waste and a final disposalhall for solidified waste. Only onemaintenance waste tunnel and the sys-tems serving the entire repository werecompleted during this stage.

Construction and installation workof the second stage of the repositoryis being conducted in 2004–2006.Completion of the previously excavat-ed maintenance waste room 2 (HJT2)began in November 2004, and thisroom will be put into operation as a fi-nal disposal facility in the first part of2005. Construction and installationwork of the previously excavated finaldisposal hall for solidified waste (KJT)will begin in early 2005 and will becompleted towards the end of 2006,simultaneously with the seepage waterpool built in the repository. The disposalhall for solidified waste will be neededfor the final disposal of waste packag-es completed at the solidification plantfrom the end of 2006 onwards.

Separate research programmeshave been planned for the study of thetransport tunnel and hall areas duringoperation.

By the end of 2004, a total volume ofover 1,100 m3 of evaporator concen-trates was treated at the caesium sepa-ration facility with 20 ion-exchanger

Solidification with cement has beenselected as the basic conditioning meth-od for Loviisa’s wet operating waste.Verification of the solidification reci-pes for evaporator concentrates andion-exchange resins with current build-ing cements continued during the yearunder review. In addition, test data wasobtained from solidification productsamples in long-term storage, the old-est of which are now as old as 21 years.

The durability test on ion-exchangeresins solidified in half-scale contain-ers in 1987 continued and the test re-sults were reported in 2004. For 17years now, the waste containers havebeen immersed in tanks filled withgroundwater at the Loviisa Power Plant;as expected, they are still in good con-dition. No damage to the concrete wallsof the containers has been detected, andthe composition of the groundwater hasremained relatively stable. Activitymeasurements for the groundwaterhave not indicated any signs of nucliderelease from the solidified products inthe concrete containers.

In 1980, inactive ion-exchange res-in used at the Loviisa Power Plant wassolidified in a full-scale final disposalcontainer. The container was kept in astore until the middle of 1983 andthereafter it has been immersed inslowly flowing fresh water at the Pyhä-koski power plant. The condition of thefinal disposal container has been mon-itored after storage of 1, 3, 5, 9, 13, 15and 21 years. Corrosion is noticeablein the lifting lugs and fastenings madeof steel, but no structural damage hasbeen detected on the concrete surfac-es of the container, nor has corrosionbeen discovered in the concrete rein-forcements of the container. The testresults were reported in 2004 simulta-neously with the test results of the half-scale final disposal containers (see Listof reports).

Operation-time studies on the final dis-posal facility continued in 2004 in ac-cordance with the monitoring pro-gramme. The objective of the pro-gramme is to study and monitor long-term changes in the properties and thebehaviour of the groundwater and bed-rock in the repository and in its imme-diate vicinity.

columns, each with a volume of 8 li-tres. The efficient separation of caesi-um from evaporator concentrates is anormal operating procedure at the pow-er plant.

30

Safety of final disposal ofoperating waste

JOINT STUDIES

The monitoring programme includ-ed monitoring the groundwater table inthe investigation boreholes aboveground once a month. The location offresh and saline groundwater in theboreholes was measured four timesduring 2004. In the repository, the con-ductivity and pressure of groundwater,and the amount of seepage water weremeasured once a month, the pressureand the amount of seepage water werealso measured continuously. The mea-surements concentrated on seepagewater pools and on five groundwaterstations built especially for this pur-pose. In 2004, the hydrogeochemicalresearch programme included watersampling and analysis from groundwa-ter stations LPVA1 and LPVA2. The sta-bility of the bedrock was mainly moni-tored by an automatic rock mechanicalmeasurement system. Visual checkingof the excavated and reinforced rocksurfaces for maintenance purposes alsocontinued in 2004.

According to the findings of 2004,the groundwater table follows varia-tions in the seawater level fairly close-ly, which is a feature typical of Hästhol-men. During construction, the ground-water table lowered a few metres in theimmediate vicinity of the repository,but a distinct rise was observed aftercompletion of the repository. Owing tothe dry summer, however, the ground-water table lowered slightly. The inter-face between fresh and saline ground-water was between the levels of about-10 and -80 m in the repository area, inother words, distinctly above the re-pository.

The electrical conductivity mea-surements of seepage water show thatthe seepage water is slightly more sa-line than in the previous year, with theconductivity varying between 1,000 and

1,600 mS/m in different parts of therepository. This means that the reposi-tory is practically completely sur-rounded by saline groundwater.Groundwater analyses show that sever-al parameters of LPVA1 (TDS, Cl, den-sity, electrical conductivity, hardness,SO4, Na, Ca, Mg, K, Fe, NH4) haveshown a slightly downward trend overthe years, but this time a slight increasecould be seen, except for sulphate,whose concentration continued to showa decrease. The measurement results ofLPVA5 have remained almost constantover the years.

The pressure values of the ground-water clearly reflect the effect of vari-ations in the seawater level. At the fivegroundwater stations, the pressure var-ies between 5 and 11 bar, thus corre-sponding more or less to the pressureat the depth levels of the stations.

The amounts of seepage water weremeasured at seven points on differentsides of the repository. After comple-tion of the excavation in 1996, the to-tal amount of seepage water was about300 l/min at its highest, from which ithas fairly steadily reduced, and wasabout 100 l/min at the end of 2004.About half of the seepage water con-tinues to come from the transport tun-nel and the rest from other facilities.The measurement results show that themaintenance waste rooms are practical-ly dry.

The results of rock mechanicalmeasurements suggest very stable con-ditions. As in the previous years, thedisplacements that have taken place inthe repository ceilings and walls arevery small, distinctly of the order ofless than 0.1 mm. Visual examinationsalso show that the repository is in goodcondition, and the subsurface drainsperform as intended.

Construction and installation work ofthe final disposal hall for solidifiedwaste (KJT) at the Loviisa Power Plantwill begin in early 2005 and it will becompleted towards the end of 2006,simultaneously with the seepage waterpool built in the repository. Updatingof the safety analysis of the repositorybegan in spring 2004 and it will be com-pleted at the end of 2005.

International development in thefield of the final disposal of operatingwaste was monitored during the yearunder review by means of conferencevisits and trade journals.

The long-term durability of concreteunder final disposal conditions is be-ing studied as a joint project by TVOand Fortum in the VLJ Repository atOlkiluoto and at the Materials and Con-crete Laboratory of Contesta Oy (for-merly owned by Fortum Technology).The research project pertains to boththe operating waste and decommission-ing waste management. The studies arediscussed in the section entitled “De-commissioning investigations” (Page31).

31

DECOMMISSIONING INVESTIGATIONS

OLKILUOTOPOWER PLANTUsed reactor internals, which are clas-sified as being intermediate-level op-erating waste, will not be mainly dis-posed of until during the decommis-sioning of the plant. The used reactorinternals are stored in the pools of theplant units and a separate inventory iskept of them. By the end of 2004 forinstance, 263 control rods and 227 coreinstruments had accumulated at theOlkiluoto Power Plant. Scrapping ofthe used steam separators and coregrids, which had been stored in thepools of the reactor hall, and their dis-posal in the VLJ Repository werelaunched. The steam separator of OL2was dismantled and the separatorgroups were disposed of in the VLJRepository.

The decommissioning plan for theOlkiluoto Power Plant was drawn up in2003 and the plan will be updated nexttime in 2008. According to the decom-missioning plan, the reactor pressurevessels of the power plant units will beremoved and disposed of in one piece.The 2003 plan was based on a powerplant unit operating period of about 40years and on controlled storage ofabout 30 years before decommission-ing. In the future, the plans will be drawnup assuming the plants will operate for60 years. According to the present plan,the intermediate- and low-level wastefrom the decommissioning and the usedreactor internals from power plant op-eration will be disposed of in an exten-sion of the VLJ Repository.

The decommissioning investiga-tions are aimed at technical and eco-nomic development of the decommis-sioning plan and specification of thebasic data for the safety assessment offinal disposal. Activity measurementsof various systems within the plant werecontinued as a means of further devel-

oping the activity inventory of the powerplant’s decommissioning waste. Theinventory of activated material will beupdated in 2005 to correspond to anoperational life of 60 years.

The database built as a part of thedecommissioning plan for the contam-inated plant section, which was com-pleted in 1989, was transferred to an-other database application. The databasehelps calculate the amounts of materi-als, the amounts of radioactive iso-topes, the working hours required fordismantling, dose rates and committeddoses of the workers, and the costs. Theupdating of the database will begin in2005.

Long-term corrosion tests of car-bon steel began towards the end of 1998in the construction tunnel of the VLJRepository. The tests are performedjointly with the concrete research insuch a way that some of the pieces ofcarbon steel are placed in the sameborehole (VLJ-KR21) as the test sam-ples of concrete while some are in aborehole of their own (VLJKR19). Lab-oratory tests in the concrete-water andbedrock-groundwater environmentswere launched in spring 1998. The cor-rosion rate of the carbon steel samplesis determined by the loss in weight andby the volumetric measurement of hy-drogen gas. The water chemistry of theboreholes is also monitored by meansof monthly pH and conductivity mea-surements. In addition, water samplesare taken annually and certain chemi-cal analyses are carried out.

Samples taken from borehole VLJ-KR21 of the Olkiluoto VLJ Reposito-ry have been examined over a test peri-od of about 4.5 years at most. At first,the corrosion rates of steel calculatedon the basis of losses in weight wereslow (about 1 µm/a), but thereafter thecorrosion rates were about 10–19 µm/a. The acceleration of corrosion hasbeen caused by the action of sulphate-reducing bacteria (SRB) in the bore-

hole. In 2004, the samples taken fromborehole VLJ-KR21 were examinedvisually, but no weight-loss measure-ments were conducted.

In 2001, tests were launched oncarbon steel plates without any poten-tial microbial nutrient sources in aborehole where no anaerobic sulphate-reducing bacteria have been detected.On the other hand, sulphate-reducingbacteria (SRB) were detected on thesurface of the steel sample taken fromborehole VLJ-KR19 in 2004. Duringthe first test-year, the corrosion rate ofthe plates was about 1 µm/a, and afterthe second test-year about 1.6 µm/a. Inthe samples examined in 2004, the cor-rosion rate was about 1 µm/a again,which means that the conditions in theborehole concerned are evidently sta-ble despite the SRB contamination. Onthe basis of the weight-loss results, thecorrosion of carbon steel continues tobe small, although rapid local corrosionhas occurred.

The samples placed in boreholeYD10 in the Olkiluoto bedrock form apart of the long-term tests begun in1985, whose purpose is to investigatethe behaviour, corrosion properties andgas generation of decommissioningwaste metals with the aid of metal sam-ples cast inside test samples. In addi-tion to reference concrete, sampleswere placed in silica concrete and sul-phate-resistant concrete. One serieswas examined from the samples re-moved in 2003. The steel bars exposedbeneath the concrete were mostly freeof rust, and rust was mainly found at thebar ends. The corrosion of steel hasbeen small in the reference concrete.The steel bar placed in silica concretewas most rusty, but the corrosion of thebar ends was most rapid in sulphate-re-sistant concrete. The corrosion rate ofthe steel bars placed in the referenceconcrete and silica concrete is 8–10µm/a in corrosion pits and about 20µm/a in sulphate-resistant concrete.

32

LOVIISA POWERPLANT

JOINT STUDIES

Operation of the Loviisa Power Plantresults in the accumulation of interme-diate- and low-level nuclear waste thatwill not be disposed of until during thedecommissioning of the plant. Thiswaste includes, e.g., used shielding el-ements, absorbers, neutron flux trans-ducers, intermediate rods of controlrods and fission chambers.

By the end of 2004, 146 usedshielding elements, 207 absorbers, 204neutron flux transducers, 128 interme-diate rods and nine fission chambershad accumulated at the Loviisa PowerPlant. Of these items, the shielding el-ements have been placed in the plantpools in the spent fuel store, and theabsorbers and fission chambers havebeen stored in specially built channelsin the spent fuel store. The neutron fluxtransducers and intermediate rods havebeen stored in corresponding channelslocated in the reactor halls.

In 1987, Fortum drew up a plan andcost estimate for the decommissioningof the Loviisa Power Plant. The decom-missioning plans were updated in 1993.The plan was based on 30 years of com-mercial power plant operation, whichis equivalent to the designed technicallife of the power plant. However, tech-nical measures may be undertaken toextend the operational life of a nuclearpower plant. New studies were com-pleted at the end of 1998, which fo-cused on the effects of revised spentfuel management and the power plantmodernisation project on the decom-missioning plans and schedules. Theoperational life of the power plant hasalso been planned to be extended to 45years, and this was considered in thestudies. According to the updated de-commissioning plan, all the radioactivesystems not necessary for the remain-ing nuclear operation (i.e. storage of thespent fuel, solidification of the wetwaste and final disposal of low- and in-termediate-level waste) at Hästholmenwill be dismantled immediately afterthe shutdown of the power plant.

The plans are revised every fiveyears. The new decommissioning planwas updated during 2003. An operation-al life of 50 years was chosen as thebasis for the updating. The updatingconsisted of the verification of the ac-tivity inventory, dismantling measures,radiation dose estimates, amounts ofthe components and packages to be dis-posed of, safety of the final disposal,and estimates of the workload and costs.

In 2004, a study was launched toestablish the volume of waste producedfrom the dismantling of the contami-nated sewage pipes left in cast concreteduring the construction of the Loviisaplant, and related costs. The study willbe completed in 2005.

To update the dismantling plan ofthe biological shield, concrete sampleswere taken in 2003 and they were ex-posed to radiation. Additional informa-tion was already obtained from the sam-ples in 2004, and the studies are beingpursued to be able to include the updat-ed dismantling plan of the biologicalshield in the decommissioning plan of2008.

It is not expedient, however, tomake any decisions regarding decom-missioning or continued operation un-til towards the end of the designed tech-nical operational life. It is also advis-able to take a final stand on whether theplant will be decommissioned imme-diately or after a certain delay, just upontermination of the power plant opera-tion, before the beginning of the de-commissioning.

The long-term durability of concreteunder final disposal conditions is be-ing studied as a joint project by TVOand Fortum in the VLJ Repository(VLJ-KR20 and VLJ-KR21) at Olkilu-oto and at the Materials and ConcreteLaboratory of Contesta Oy at Myyrmä-ki, Vantaa. The project was launched in1997. This research project, originallyco-ordinated by Posiva, concerns boththe operating waste and decommission-ing waste management. In 2003, TVO

assumed responsibility for co-ordinat-ing the project. The purpose of the stud-ies is to realistically assess the long-term behaviour and degradation of con-crete in the bedrock-groundwater en-vironment that corresponds to operat-ing conditions. The objective is to es-tablish, using modern concrete technol-ogy, the durability and lifespan of theplanned concrete types with differentcompositions under the real final dis-posal conditions and under accelerat-ed laboratory conditions. Special em-phasis will be placed on establishing themost durable concrete compositionsunder prevailing conditions, which willmeet the requirements set for thelifespan.

With regard to the testing of con-crete ingredients, the basic tests ofconcrete technology carried out during2004 included destructive tests, defor-mation measurements and analyses ofthe microstructure. Of the long-termtests, the laboratory tests concernedthe carbonation of concrete test sam-ples and the penetration of corrosivecomponents; furthermore, analyses ofthe microstructure were performed andmicrostructural maps were determinedfor the selected concrete test samplesin so far as test samples still remained.The long-term tests also included anal-ysing the water of the test-sample stor-age pool used for the laboratory testsafter a storage period of six years.

With respect to the long-term fieldtests, samples were taken in the autumnof 2004 from the concrete test sam-ples placed in borehole VLJ-KR20. Theresearch conducted on the test samplesincluded the penetration of corrosivecomponents and analyses of the micro-structure. The concrete test samplesplaced in borehole VLJ-KR21 wereexamined visually. As stated above in thedecommissioning investigations con-cerning carbon steel samples, the wa-ter chemistry of the boreholes (VLJ-KR19–21) is monitored by means ofmonthly pH and conductivity measure-ments and, in addition, water samplesare taken annually and certain chemi-cal analyses are carried out.

33

COMMUNICATIONS AND CONTACTS

During the year under review, the sub-jects of external communications in-cluded the choice of the contractor forONKALO, the beginning of the exca-vation of ONKALO, and the progressof tunnel work. Posiva also demon-strated the construction of ONKALOat the Environment 2004 Fair in Hel-sinki.

An open house event was arrangedfor the general public at Olkiluoto in

the autumn. Some 1,000 visitors, main-ly from the Eurajoki and Rauma areas,became acquainted with the construc-tion of ONKALO during the day.

Plenty of information material re-lated to ONKALO was produced dur-ing the year under review. In additionto brochures, an animation recorded inDVD format was produced to illustratethe construction technology of ONKA-LO and the progress of work. Further-

more, the construction of ONKALOand the change it has brought about inPosiva’s operations have guided theoverall updating of the visual and fac-tual content of the Company’s web site.

The ‘Posiva Tutkii’ bulletin pub-lished as a supplement to the ‘Uusi Rau-ma’ and the ‘Porin Sanomat’ newspaperscovered the preparations for the con-struction of ONKALO and the progressof the excavation.

34

QUALITY MANAGEMENT ANDENVIRONMENTAL MANAGEMENT

Posiva’s operations are aimed at thesafe implementation of nuclear wastemanagement in accordance with theneeds of its owners and other clients,while protecting the environment andfulfilling the requirements set by soci-ety. Posiva has been upgrading qualityever since the Company was estab-lished. At Posiva, company operationsare guided by the operating system,whose purpose is to verify the system-atisation of operations and the achieve-ment of the targets in accordance withthe company strategy. During 2004, theCompany’s main, production and sup-port processes were described in theoperating system. A self-assessmentevent of the support processes was ar-ranged in autumn 2004 with a view toidentifying major points of develop-ment in these processes.

During 2004, the efficiency andreliability of the system in relation tothe set targets were assessed by Posi-va’s internal audits. The internal auditswere concerned, for instance, with riskmanagement and the Company’s envi-

ronmental aspects. The results of theaudits brought important subjects ofdevelopment to light to improve theefficiency of operations and the oper-ating system.

The capability of 18 suppliers tofulfil the technical, economic, qualityand environmental requirements wasassessed during 2004. The operatingsystems that are being applied and theirdevelopment potential were surveyed.The functioning of 13 organisations wasassessed by means of the audits of sup-pliers during the year under review.

Instructions with a view to assur-ing the quality of research, developmentand design work were specified. In as-suring the quality, Posiva also employedan outside expert group to audit thematerial produced by Posiva. The qual-ity management of the ONKALOproject concentrated on drawing up thequality assurance programme and ondetermining the guidelines that supportthe operations.

Quality assurance of the construc-tion of ONKALO was developed by

determining the functions during con-struction important for long-term safetyand by dividing them into three classeson the basis of their significance. Thefollowing functions were considered tobelong to the most significant class withregard to long-term safety: passing ofhazardous materials into ONKALO,control of water seepages, drillingsperformed in the area of ONKALO, andthe damage zone caused by excavation(EDZ). Appropriate quality assuranceinstructions were drawn up for thesefunctions.

As far as TVO and Fortum are con-cerned, the nuclear waste managementoperations are within the scope of thequality assurance programmes of nu-clear power plants approved by the Ra-diation and Nuclear Safety Authority(STUK) in accordance with Section 36of the Nuclear Energy Decree andGuides YVL 1.1 and 1.9. Both nuclearpower plants have a certified environ-mental management system in accor-dance with the ISO 14001 standard forenvironmental management.

35

COSTS

RESEARCH

Research area Costs(EUR million)

Planning, co-ordination, information activities and general studies 0.5

Management of spent fuel and high-level waste 13.5

Management of intermediate-level and low-level waste 0.1

Decommissioning and decommissioning waste 0.2

Total 14.3

SUMMARY OF THE RESEARCH COSTS IN 2004

FINANCIAL PROVISION FOR NUCLEAR WASTE MANAGEMENT

The total cost of the nuclear waste man-agement research programme wassome EUR 14.3 million. The cost esti-mates for the research programme in

2004 were about EUR 11.2 million. Theresearch programme was mostly imple-mented as planned.

The above-mentioned costs do not

include Posiva’s research assignmentssponsored by Tekes, the National Tech-nology Agency of Finland.

Funds for the future costs of nuclearwaste management are collected by theState Nuclear Waste Management Fund.The fund target is determined accord-ing to the liability of nuclear wastemanagement to be confirmed each year.The liability comprises the future costsof the management of all wastes accu-

mulated by the end of the year in ques-tion.

EUR 763.8 million was assessed asthe fund target for TVO in 2004, thecorresponding amount for Fortum be-ing EUR 570.2 million.

The Ministry of Trade and Industry(KTM) confirmed a liability amount of

EUR 792.7 million for TVO’s nuclearwaste management at the end of 2004and, based on this amount, a fund targetof EUR 792.7 million for 2005. ForFortum, KTM confirmed a liabilityamount of EUR 596.4 million and, ac-cordingly, a fund target of EUR 596.4million for 2005.

36

POSIVA 2004-01Reduction of Uranyl Carbonate andHydroxyl Complexes and NeptunylCarbonate Complexes Studied withChemical-Electrochemical Methodsand Rixs SpectroscopySergei Butorin, Joseph NordgrenUppsala UniversityKaija OllilaVTTYngve AlbinssonChalmers University of TechnologyLars WermeSKBMay 2004ISBN 951-652-127-433 p.

POSIVA 2004-02Modelling Gas Migration inCompacted Bentonite: GAMBIT ClubPhase 3 Final ReportA. R. Hoch, K. A. Cliffe, B. T. Swift,W. R. RodwellSerco AssuranceApril 2004ISBN 951-652-128-2144 p.

POSIVA 2004-03Dissolution rates of unirradiated UO2,UO2 doped with 233U, and spent fuelunder normal atmospheric conditionsand under reducing conditions usingan isotope dilution methodKaija OllilaVTT ProcessesYngve AlbinssonChalmers Technical UniversityVirginia OversbyVMO KonsultMark CowperAEA TechnologyDecember 2004ISBN-951-652-129-0110 p.

LIST OF REPORTS 2004

POSIVA 2004-04Updated assessment of health risks onthe transportation of spent fuelVesa Suolanen, Risto Lautkaski,Jukka Rossi, Tapio Nyman,Tony Rosqvist, Sanna SonninenVTT ProcessesMay 2004ISBN-951-652-130-4(in Finnish, abstract in English)156 p.

POSIVA 2004-05Localisation of the SR 97 ProcessReport for Posiva’s Spent FuelRepository at OlkiluotoEditor:Kari RasilainenMay 2004ISBN-951-652-131-2168 p.

POSIVA 2004-06Future Climate Scenarios forOlkiluoto with Emphasis onPermafrostJannika CedercreutzHelsinki University of TechnologyDecember 2004ISBN-951-652-132-072 p.

Fortum Power and Heat Oy,TJATE-G12-00082Long-term durability experimentswith concrete-based waste packagesin simulated repository conditionsAri Ipatti and Juha RatvioContesta OyVantaa, December 200483 p.

Teollisuuden Voima Oy

FI-27160 OLKILUOTO, Finland

Tel. +358 2 83 811

Fortum Power and Heat Oy

P.O.Box 100

FI-00048 FORTUM, Finland

Tel. +358 10 4511

Posiva Oy, FI-27160 OLKILUOTO, Finland

Tel. +358 2 83 7231, Fax +358 2 8372 3709

www.posiva.fi