The 4th International Thorium Energy Conference, ThEC13, at CERN, in Geneva Switzerland, October 27 to 31, 2013.

S. Ganesan RAJA RAMANNA FELLOW of the DAE, Bhabha Atomic Research Centre, Mumbai

 & Professor, Homi Bhabha National Institute (HBNI), Mumbai& Scientific Consultant (Hon) to the Office of the PSA, GOI, Delhi

Reactor Physics Design Division Reactor design and development Group

 Bhabha Atomic Research Centre Trombay

 Mumbai 400085

Email: ganesan@barc.gov.in&

ganesan555@gmail.com

Nuclear Data Development Related to Th‐U Fuel Cycle in India

I would like to express my sincere thanks

to

Prof. Jean-Pierre REVOL for inviting me to deliver a talk in ThEC13.

&

to BARC/DAE authorities for enabling my participation in ThEC13.

Discussed already by P. K. Vijayan, Session 2, This ThEC13 Conference. Also P.K. Wattal, ThEC13

•http://www.dae.gov.in/ and various links therein.•http://www.npcil.nic.in/main/AllProjectOperationDisplay.aspx•http://www.npcil.nic.in/main/ProjectConstructionStatus.aspx•http://www.igcar.gov.in/

Indian SituationThe currently envisaged main new components, included in the Indian road map for Advanced Nuclear Power Systems, comprise the following (P.K. Vijayan, ThEC13): 

•Advanced Heavy Water Reactor (and other thorium fuelled reactor systems (Ref. R.K. Sinha, A. Kakodkar, “Design and development of the AHWR—the Indian thorium fuelled innovative nuclear reactor,” Nuclear Engineering and Design, Volume 236, Issues 7–8, April 2006, Pages 683-700).•Advanced fuel cycle (front end and back end) facilities (Wattal, ThEC13)•Compact High Temperature Reactor •Accelerator Driven Systems (Degwekar, ThEC13)•A number of slides on the above Indian activities on thorium were shown by P.K. Vijayan in ThEC13 here and are not repeated here to save space.

We will mainly focus on Indian nuclear data science activities for thorium fuel cycle.

•Nuclear power is a viable option for meeting energy needs in India

•Indian approach involves a closed fuel cycle involving multiple fuels.

•As multiple fuel cycles (e.g., U-Pu, Th-U), with the option of closing the fuel cycle are envisaged, the nuclear data requirements that are needed to develop the new systems with high burnup are demanding and include all the range of actinides and fission products for multiple fuels.

Challenges in Basic Nuclear Data Physics for Indian Nuclear Industry

Nuclear reactor is A PHYSICS MACHINE

Physicists have a great role in designing the best nuclear reactor

design; the best nuclear reactor design is yet to be made.

The speaker believes that the best reactor design (Generation N)

•not even remotely be accident prone during the entire fuel cycle•with minimum radioactive waste •with maximum tolerance of normal, and, •even remotely possible operator errorsis yet to be made.

Role of Multiphysics Multiscale Modeling MMM3 with “big” data science.

•AN EXAMPLE TO ILLUSTRATE THAT NEW CONCEPTS (e.g., such as energy amplifier) need new data

S. Ganesan, “Nuclear Data Requirements for Accelerator Driven Sub-critical Systems - A Roadmap in the Indian Context,” Indian Journal: PRAMANA, Vol. 68, No. 2, pp. 257-268 (Feb. 2007).

The basic nuclear data physics research has been essential in shaping concepts of Energy Amplifier designs by Prof. Carlo Rubbia. Scientific foundation is on a better scientific basis with better physics data.

Indian Context:

Importance of nuclear data was recognized in 2004.

Many ND activities started as DAE declared nuclear data as

a thrust area.

Nuclear Data Centre was formed in 2009 11

Nuclear Data Physics Centre of India (NDPCI) has been formed.

NDPCI has projects / collaborations with universities across India.

Activities of Nuclear Data Physics Centre of India include the following:

• Measurement of neutron and charged particle induced cross-section (Th-U fuel cycle, ADSS, AHWR, shielding, fast reactors and other programmes of DAE, also medical isotopes production

• Compilation and evaluation of nuclear reaction and nuclear structure; EXFOR Compilations. ENSDF related compilations.

• DAE-BRNS sponsored NDPCI theme meetings and national conferences on topics in nuclear data physics

• Advanced reactor applications to enable use of updated nuclear data libraries in plug-in format such as for discrete ordinates and Monte Carlo codes

• Coordination on nuclear data physics involving IAEA NDS and be a single window from India to IAEA NDS.

• International collaborations with CERN n_TOF under BARC MOU, Korea, IAEA CRPs

• Identification of faculty & support for formation of useful local neutron data centres in universities and institutes.

India is making rapid advances in nuclear data science since 2004. We need to do a lot more. The world has taken note of the base technology activities of India in nuclear data science that includes nuclear data for thorium fuel cycle. India has formed a Nuclear Data Physics Centre of India, a virtual centre. Efforts are on to make a physical centre for the NDPCI.

Indian EXFOR compilation workshops in nuclear data compilations have become a role model. India is a member of NRDC club (International Nuclear reaction data Compilation network) since Sep. 2008. India has made more than 220 EXFOR entries as accepted by the IAEA

India has initiated base technology efforts to start Indian evaluations of data

India is making efforts in interfacing ENDF/B nuclear data files to Indian Monte Carlo codes (equivalent to MCNP standards). Long term project.

India is a contributor to the ICSBEP Benchmarks NEA-DB/US-DOE. KAMINI, PURNIMA-II and PURNIMA-I.

India is making progress in digesting methodolgy of covariances in nuclear data

Examples of Nuclear Data Science Workshops in India (2012-2013) aimed at Indian interests such as

thorium utilization.

Workshop on Covariances in Nuclear Data, 16-19 December 2013, Homi Bhabha National Institute (HBNI), Mumbai), Maharashtra State

Workshop on Surrogate Reactions and Its Applications, 24-25 January 2013, M.S. Univ. of Baroda, Vadodara, Gujarat State

Workshop on Evaluation of Nuclear Structure and Decay Data(30 Sept - 19 Oct 2012), Variable Energy Cyclotron Centre Kolkata, West Bengal State

Nuclear data needs for thorium fuel cycle in Indian context. Generic issues

India’s programme of nuclear data science includes five base technologies:1.Nuclear data physics experiments; Cross section measurements, covariances2.Measured raw data compilations. Covariances; Digitization3.Cross-section evaluations includes nuclear models, statistical tools4.Cross section processing 5.Integral experiments (How to reduce the number of integral expts?)6.Neutron-photon coupled transport calculations and response functions. (reactor Design with plug-in nuclear libraries). Use of covariances to define error margins due to uncertainties in nuclear dataThe process of getting the working libraries for design calculations requires an iterative sequence of events to yield a quality assured transport cross section library. Steps 1 to 5 involve doing science with efforts of magnitude 3 orders or more and lead time of years, than reactor design work that starts from plug-in nuclear data libraries.

Indian Context:

NDPCI OPERATES IN VIRTUAL MODE AT THIS TIME.

Indian nuclear data activities in the past generically encompassed historically the user oriented approach starting from the basic evaluated nuclear data files distributed by the IAEA. India is now graduating to be a contributor to nuclear data generation.

IAEA-TECDOC-336 (1985)

India’s first ENDF/B file INDL Project by Hans Lemmel, IAEA

Mirror of IAEA Nuclear Data Services in India

The online nuclear data services mirror the nuclear data website of the Nuclear Data Section of the International Atomic Energy Agency (IAEA) in Vienna.

NDS primary server (in Vienna)

Public client

NDS mirror server(in India)

IAEA NDS MIRROR SITE SET-UP

www-nds.indcentre.org.in

2Mbps link

www-nds.iaea.org

INTERNET

Under this arrangement, online-updating every 12 hours is performed in the mirror with the IAEA website through a 2MB direct link. The server is being maintained by BARC Computer Division - with manpower and machinery. It offers faster downloads.

20

http://www-nds.indcentre.org.in is the Mirror website in BARC that mirrors the IAEA website http:// www-nds.iaea.org

The WIMS-D/4 code is a freely available thermal reactor physics lattice cell code that is widely used in many laboratories for thermal research reactor and power reactor calculations. It should be noted that the WIMS library associated with the WIMS-D/4 package is the 1981 -69 group library generated in the United Kingdom using evaluated nuclear data from the early 1960s.

WIMS Library Update Project IAEA Coordinated Research Project . 1998-2002. http://www-pub.iaea.org/MTCD/publications/PDF/Pub1264_web.pdf

For U-235, for instance, we produce here on the left a plot of “eta” using the XnWLUP software . Below the the ratio is plotted as [Eta of ENDF/B-VII.0 / 1981 data )-1.00] in percent.The values of eta correspond to the infinite dilution cross sections, comparing the 1981 set with ENDF/B-VII.0 based 69 group multigroup cross sections. From physics point of view “eta” represents the net number of neutrons released per neutron absorbed and the effective “eta” over the neutron spectrum is essentially the infinite medium ultiplication factor, K-inf.

The target accuracy in K-inf is 1mk and this gives the needed target accuracy for “eta” parameter as 0.1%. We see that the 1981 set and the ENDF/B-VII.0 data set differ by about -11% to 25% in some energy groups. Around the energy of 0.025 eV, the 2006 data is 0.5% larger than the 1981. This is the situation even with the main fissile material that is well investigated.

1981 data of eta for 235U compared with IAEA WLUP values

India participated in and

benefitted from the IAEA Co-

ordinated Research Project on

“Evaluated Data for the

Thorium-Uranium Fuel Cycle,”

2003-2006.

https://www-nds.iaea.org/publications/tecdocs/sti-pub-1435.pdf

BARC-TIFR Pelletron Machine, Mumbai

Measurements, Covariance error matrix specification

European Physical Journal A 48, 35 (2012), Team lead by H. NaikP. M. Prajapati, H. Naik, S. V. Suryanarayana, S. Mukherjee, K. C. Jagadeesan,S. C. Sharma, S. V. Thakre, K. K. Rasheed, S. Ganesan and A. Goswami, “Measurement of the neutron capture cross-sections of 232Th at 5.9 MeV and 15.5 MeV”

This paper & the value of 234Pa(n,f) (the only experiment thus far) is quoted in 2012/2013 Karlsruhe International wall chart.

Indian experimental data 232Th(n,2n) 231Th. Available in the IAEA EXFOR database

Indian measurements of 232Th(n,g) 231Th are in the 0.5 to 15 MeV energy range using 7Li(p,n) reactions

Indian measurements of nuclear data

Surrogate nuclear reaction approach in India is discussed as an interesting example in the

next few slides.

Data from Surrogate Approach at BARC-TIFR• 233Pa(n,f)/235U(n,f) by 232Th(7Li,α)234Pa*(fis) /

232Th(7Li,d)236U*(fis) 233Pa: 26.975 days B.K. Nayak et al., PRC 78 (2008) 061602 (EXFOR 33023)

• 239Np(n,f)/241Pu(n,f) by 238U(6Li,α)240Np*(fis)/238U(6Li,d)242Pu*(fis) 239Np: 2.356 days

240Np(n,f)/241Pu(n,f) by 238U(7Li,α)240Np*(fis)/238U(7Li,t)242Pu*(fis)

240Np: 61.9 mins V.V. Desai et al., PRC 88(2013)014613 (to be in EXFOR)

235U(n,f) and 241Pu(n,f) are used as reference cross sections (well determined by direct method).

• 241Pu(n,f)/235U(n,f) by 240Pu: 14.325 years 238U(6Li,d)242Pu*(fis)/232Th(6Li,d)236U*(fis)

Both 241Pu(n,f) and 235U(n,f) are well determined by direction method. → Benchmark of the surrogate approach.

V.V. Desai et al., PRC 87(2013)034604 (to be in EXFOR)

Bhabha AtomicResearch Centreand the Tata Instituteof Fundamental Research14 MV Pelletron

EXCITING SURROGATE TECHNIQUE

The 2 day national NDPCI workshop at Vadodara, 24-25 January 2013 discussed this technique.

You do not have neutron beam. You do not have a target of an unstable nuclei. How do you get the cross section data for interaction of neutrons with unstable target nuclide?

Use of surrogate nuclear reactions.

Surrogate Reaction Approach for 233Pa(n,f)

Determination of 233Pa (T1/2~27 days) fission cross sections

6Li 232Th234Pa*

α

fission

n233Pa(22 min)

234Pa* fissionReaction of interest

Surrogate reaction

+

++

Surrogate Reaction Approach for 233Pa(n,f)

6Li

232Th

234Pa*

α

fission

Surrogate reaction

++

Nα = # of 234Pa compound formation = # of α detectionNα-f= # of 234Pa compound fission = # of α and fission fragments detection (coincidence)

→ r = Nα-f / Nα = Γf (234Pa*)/Γtot(234Pa*) - branching ratio of 234Pa* to fission

σ[233Pa(n,f)] = compound formation cross section σcn[233Pa+n] ×r Compound formation cross section: determined by optical model r: experimentally determined. A review paper on Surrogate approach: See, for instance, J.E. Escher et al., Reviews of Modern Physics, 84(2012)353.

EXCITING SURROGATE TECHNIQUE233Pa(n,f) Cross Section

Incident Energy (MeV)

0 5 10 15 20

Cro

ss

Se

cti

on

(b

arn

s)

-0.5

0.0

0.5

1.0

1.5

2.02004 Tovesson2004 PetitPresent ExperimentEmpire 2.19 (With Barrier Formula)

EXFOR Entry completed

EXFOR Entry nos:33023 and D6075 (CORRECTED FOR 2 INADVERTENT ERRORS IN THE PAPER). See Figure on the left, Thanks, N. Otsuka.

232Th(6Li, a)234Pa 232Th(6Li, d)236U

Data in EXFOR database after correction

240Np: 61.9 mins239Np: 2.356 days

234Pa(n,f) (to be published)• 232Th(7Li,α)235Pa*(fis) / 232Th(7Li,t)236U*(fis) was used.

Equivalent Neutron Energy (MeV)

6 8 10 12 14 16 18 20

Cro

ss S

ection (bar

ns)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Present ExperimentEMPIRE-3.1 (BF)EMPIRE-3.1 (RIPL-1)

See the abstract submitted by V.V. Desai, B.K. Nayak, A. Saxena

T1/2 of 234Pa is ~6.7 hr.

No 234Pa(n,f) cross sectionin EXFOR except for one for the thermal neutronsby 233Pa(2n,f) method atAPSARA reactor (BARC)with fission track(H. Naik et al.,Eur. Phys. J. 47(2011)100; EXFOR 33036.)

To be published.

PHYSICAL REVIEW C 88, 014613 (2013)

Compilation of raw experimental nuclear physics

data is a challengeEXFOR WORKSHOPS IN INDIA HAVE EVOLVED AS A NEW & UNIQUE MANGERIAL INITIAVE AND HAVE BEEN PHENOMENALLY SUCCESSFUL.

Introduction of EXFOR culture in people including in basic nuclear physics has become relatively an easier task with the new managerial initiatives of holding EXFOR workshops in India.

Through the EXFOR Workshops, the NDPCI has been phenomenally successful to bring people in various fields (e.g., Nuclear Physics, Reactor and Radiochemistry Divisions of BARC, IGCAR, VECC etc.) and students and staff from various Universities across India. A very unique activity. Both experimentalists, theoreticians were covered.

Indian EXFOR Compilation Workshops

1. DAE-BARC theme meeting on EXFOR compilation of nuclear data”, Mumbai 4 to 8 September 2006.

2. DAE-BARC theme meeting on EXFOR compilation of nuclear data” , BARC, Mumbai, 29 September to 2 October 2007.

3. The 3rd DAE-BARC theme meeting on EXFOR compilation of nuclear data”, Jaipur University, Jaipur, 3 to 7 November 2009.

4. The 4th DAE-BARC theme meeting on EXFOR compilation of nuclear data”, Punjab University, Chandigarh, 4 to 8 April 2011.

5. The 5th DAE-BARC theme meeting on EXFOR compilation of nuclear data”, Banaras Hindu University, Varanasi, 18 to 22 February 20136. 2014 EXFOR workshop, in Banglaore (Proposal)

International Network ofNuclear Reaction Data Centres (NRDC)

NNDC　 NEA-DB IAEA-NDS CJD, CAJaD, CDFE, CNPD ATOMKI CNDC JCPRG, JAEA KAERI UkrNDC BARC

NDPCI is responsible for all EXFOR compilations in India.BARC was invited and joined as a full member of NRDC in September 2008.

Number of Indian Nuclear data Physics Experiments Compiled by India

# of all experiments by all countries in EXFOR (/10)

# of experiments compiled by India

More than 200 Indian experimental works have been compiled bythe Indian group since 2006 and accepted by the IAEA.

1st workshop (2006) in BARC

•The safety and operational requirements of existing power plants have been engineered with a number of one-to-one mockup experiments providing adequate and conservative safety margins. • Basic physics understanding and better data physics of nuclear interactions are continuing to be rigorously sought by nuclear design communities in order to extrapolate to states of the power plant in conditions not covered in one-to-one mock experiments.

An Interesting Example of an Indian Operating PHWR

Influenced by Need To Use Update Nuclear Data in Design

Manuals

BETTER NUCLEAR DATA

For safe operation of existing reactors: A practical example

In 2004, an incident involving power rise took place in KAPS, Unit 1. Nat- UO2, D2O, PHWR 220 MWe unit. A public release dated April 22, 2004 by the Atomic Energy Regulatory Board provides the details of this incident.

www.aerb.gov.in/prsrel/prsrel.asp

On March 10, 2004, KAPS-1 experienced an incident involving incapacitation of reactor regulating system, leading to an unintended rise in reactor powerfrom 73%FP to near 100%FP, with trip occuring on Steam Generator DELTA T High

Level 2 on INES Scale.

KAPS-1 PSS ION CHAMBERS READING DURING POWER INCREASE

70

75

80

85

90

95

100

9:08

:00 9:

09:10

9:10

:20 9:

11:30

9:12

:40 9:

13:50

9:15

:00 9:

16:10

9:17

:20 9:

18:30

9:19

:40 9:

20:50

9:22

:00 9:

23:10

9:24

:20 9:

25:30

9:26

:40 9:

27:50

9:29

:00 9:

30:10

TIME

POW

ER (%

FP)

CH-D % FP

CH-E % FP

CH-F % FP

A practical exampleAn incident involving power rise took place in KAPS, Unit 1. Nat- UO2, D2O, PHWR 220 MWe unit. A public release dated April 22, 2004 by the Atomic Energy Regulatory Board provides the details of this incident. On March 10, 2004, KAPS-1 experienced an incident involving incapacitation of reactor regulating system, leading to an unintended rise in reactor powerfrom 73%FP to near 100%FP, with trip occurring on Steam Generator DELTA T High Level 2 on INES Scale.

The FTC is due to the combined effect of Doppler effect and fuel re-thermalization effect. In a Pressurized Heavy Water Reactor, the precise cross-over point in burnup where the FTC becomes positive depends on many parameters such as the temperature range and 19 versus 37 rod cluster. The 27 group wims1981 library has a cross over point, for FTC at about 12000MWD/Te burnup; at about 9400MWD with the same but 69-group library, at about 6000MWD for a 19 rod cluster with the new “iaea.lib” library and at about 4500MWD for 37 rod cluster of PHWR with the “iaea.lib” library. The KAPS-1 overpower transient could be explained only with the use of new WLUP libraries.

THORIUM LOADING IN

PHWRs

Thorium bundles were loaded in Indian PHWRs for initial flux flattening from KAPS Unit 1 onwards. Identical loading of thorium bundles also used in KAPP-2, KAIGA-1 and 2 and RAPS-3 and 4 to attain flux flattening in the initial core. 12 bundles in each channel; Bundle numbers increasing in the direction of bundle movement during refuelling; Numbers on the core map indicate position of thorium bundle in the channel.

Kamala Balakrishnan, Anil Kakodkar,"Optimization of the initial fuel loading of the Indian PHWR with thorium bundles for achieving full power, “Annals of Nuclear Energy, Volume 21, Issue 1, January 1994, Pages 1-9

Surendra Mishra, R.S. Modak, S. Ganesan,“Optimization of Thorium loading in fresh core of Indian PHWR by evolutionary algorithms,”Annals of Nuclear Energy, Volume 36, Issue 7, July 2009, Pages 948–955

Several loading patterns are acceptable. The one used in KAPPs is one among these.

The Post Irradiation Examination was carried out for one of the discharged bundles from KAPS- Unit 2, which had seen 508 FPDs after 4.5 years of cooling

About five grams of the irradiated bundle were cut off from the edge pellet of the outer ring of the irradiated 19-rod thorium cluster, and was supplied for dissolution studies and separation of the uranium isotopes.

Analyzed experimentally by alpha spectrometry for 232U and by thermal ionization mass spectrometry for 233U, 234U 235U 236U by two different groups in BARC .

Analyses of irradiation of thorium bundles in PHWRsIdentical loading of thorium bundles was used in KAPP-1 & 2, KAIGA-1 and 2 and RAPS-3 and 4 to attain flux flattening in the initial core. The thorium oxide used is about 400 kg in all the 35 bundles put together in a reactor. The bundles loaded in KAPP-1 & 2, KAIGA-1 and 2 and RAPS-3 and 4 have already been discharged from the core. Samples were obtained from one of the irradiated ThO2 bundles and have been analyzed experimentally by alpha spectrometry for 232U and by thermal ionization mass spectrometry for 233U, 234U, 235U and 236U by two different groups in BARC. The previous analyses by two teams in BARC gave a factor of 6 to 8 under-predictions in the production of 232U. The discrepancy was traced to be due to the fact that the effective one-group values of cross sections for isotopes of thorium fuel cycle and the use of assumptions in the ORIGEN code are applicable to case of thorium traces in nat-U rods but not for the irradiation of thorium rods in our PHWRs.

10-January 2006TSC PRESENTATION

SUMMARY OF EXPERIMENTAL RESULTS: EXPERIMENTAL BENCHMARK IN PROGRESS

• J-11 (9) ThO2 bundle• 508 FPDs irradiation time ; 4.5 years cooling time

– PIED made available about 5 gms from above bundle– Dissolution studies (PDD, NRG)– Gamma spectrometric analysis (RCD )– Burnup determination - TIMS ( FCD)

Burnup 232U/233UCalculated 10,500 MWd/t ~ 100 ppm ( old) (RPDD)

540 ppm (new (RPDD)Measured 569 ppm ( FRD)

12,500 MWd/t (FCD) 549 ppm (FCD)10,800 MWd/t (RCD)

Future work • PIE of KAPS-2 Thoria bundles ; J-rods of CIRUS• FBTR thoria subassemblies - measurements of 232U & 233U

CORE CALCULATIONS BASEDComparison of the Isotopic Contents in (J-11-9) Fuel

Rod – 3rd Ring; KAPP-2 (PHWR) C/E values for weight percent.

232U 0.85233U* 1.00232U/233U(ppm) 0.86234U 0.96235U 0.92236U 0.86Sum (232U, 233U, 234U, 235U and 236U) 0.98

INDIAN CODES ARE USED: PHANTOM-CEMESH code system.

Explicit treatment of (n, 2n) cross sections at Lattice LEVELLattice cell code module in PHANTOM: CLUB;

*233Pa has been added.

The formation of 232U in thorium

• mainly takes place by the following reactions:

232Th (n, 2n) 231Th (-) 231Pa(n, ) 232Pa (- ) 232U

• 232U is also formed in-situ with burn-up and thus 232U is also formed in small amounts through the breeding reaction from 232Th:

232Th (n, ) 233Th (-) 233Pa (- ) 233U(n, 2n) 232U.233Pa (n, 2n) 232Pa (- ) 232U

This 232Th(n,2n) reaction though occurs above 6.3MeV plays havoc in thorium cycle even in thermal reactors where the flux above 6MeV is just 0.05%. Also provides proliferation resistance

EA-ADS: ~700ppm (Calc)

PHWR-India: 550ppm (Exptl)

AHWR-India: 1700ppm (Calc)

Fast Breeder Test Reactor : Calc : 5-10 ppm

THORIUM IN FBTR

232U content is estimated to be a FACTOR OF 150 to 250 lower!!!

The reasons for the expected low ppm (less than 10ppm) of 232U in Fast Breeder Test Reactor

Nuclear data and physics considerations

•Nickel reflector brings the neutrons below the threshold of (n, 2n) reaction in 232Th;

•The effective 231Pa (n, γ) cross section is much lower in a fast spectrum as the capture cross section falls rapidly with increasing energy.

•Thirdly, the accumulation potential of 233U produced is more in saturation in a fast spectrum making the ppm content of 232U in 233U much smaller

•FACTOR OF 250 lower!!! To be verified by PIE

EXPERIMENTAL CRITICALITY BENCHMARKS NUCLEAR

REACTOR DATABASE.

E: experimental value: Benchmark experiment: (E)

C: Calculated value of integral parameter (k-eff, control rod worth, void coefficient, fuel temperature coefficient, shield thickness, burnup evolution, decay heat, foil dosimetry based spectrum determination etc.)

Nuclear data uncertainties dominate other errors in many cases.

C ± SQRT {VAR (C)}--------------------------- E ± SQRT{VAR (E)}

C ± SQRT {VAR (C)}--------------------------- E ± SQRT{VAR (E)}

•Var (C) has many components---Arising from many causes, such as,•Nuclear data (In some cases, the major part of the total uncertainty).•Approximations in modelling reactor calculations, such as

•Uncertainty in composition including in minor and major impurities, •Uncertainties in geometry (tolerances),•Numerical approximations, •Treatment and collapsing of nuclear data (multigroup) etc .

•Var (E): Error in experiment al measurement of a given integral value Plus •Uncertainty in system charaterization; [Benchmark uncertainty].

It is useful to know the confidence level /uncertainties in calculated Safety related feedback coefficients. Example: Advanced Heavy water Reactor under development, See Umasanakari Kannan and S. Ganesan, “Analysis of coolant void reactivity of Advanced Heavy Water Reactor (AHWR) through isotopic reaction rates,” Nuclear Science and Engineering (Feb. 2011).

http://icsbep.inl.gov

INTEGRAL NUCLEAR DATA VALIDATION STUDIES

India is a contributor to the experimental nuclear criticality benchmarks of the International Criticality safety Benchmark Evaluation Project (ICSBEP) of the US-DOE/NEA-DB.

History of successful integral criticality benchmarking tasks by the DAE/ India

•2005: KAMINI experimental benchmark ( ICSBEP Reference: U233-MET-THERM-001 )

•2008: PURNIMA-II experimental benchmark ( ICSBEP Reference: U233-SOL-THERM-007 )

•2012: PURNIMA-I (Completed) ( ICSBEP Reference: PU-COMP-FAST-004 )

For details, please visit the URL: http://icsbep.inl.gov/

Our calculations show a sizable positive temperature coefficient of reflector in

KAMINI reactor

We use the ICSBEP specifications for the KAMINI calculations.

What is thermal neutron scattering data?

Incident neutron energies LESS THAN 4 eV. Below 4 eV, Neutron scattering cross sections are affected by chemical binding (solid, liquid, gas) . Neutrons can gain or loose energy (up-scattering possible) - by exciting molecules/atoms or gain energy from molecules via inelastic processes.

In thermal reactors, ignoring thermal scattering effects (using free hydrogen cross sections in design calculations instead of H bound in H22O, for instance) is a blunder. Can cause too large, up to 50 mk error in criticality depending on the content of thermal neutrons in the system.

Thermal scattering data is important in ALL reactor designs, fuel reprocessing facility designs, fuel transport, radiation shielding optimization, design of ultra-cold neutron sources, even in fusion systems where thermal neutrons may be present.

Creation of Indian benchmarks for nuclear data validation•The KAlpakkam MINI (KAMINI) reactor is a 233U fueled light

water moderated and beryllium oxide reflected research reactor. Our report on KAMINI has been published as a benchmark of international quality. India thus is formally listed as a contributor since 2005 in the International Handbook of Evaluated Criticality Safety Benchmark (ICSBEP) experiments published by the USDOE-NEA.

KAMINI is a 233U fueled, light water moderated, natural convection cooled, and beryllium oxide reflected 30 Kilo Watt power research reactor. The thermal reactor is a highly reflected critical system with the use of BeO as reflector.

The reactor is currently operating at the Indira Gandhi Centre for Atomic Research at Kalpakkam, India. ICSBEP Reference: U233-MET-THERM-001. India contributed KAMINI to ICSBEP handbook in 2005.

http://icsbep.inl.gov

KAMINI is a 233U fueled, light water moderated, natural convection cooled, and beryllium oxide reflected 30 Kilo Watt power research reactor. The thermal reactor is a highly reflected critical system with the use of BeO as reflector.

KAMINI REACTOR PRESENTLY OPEARATING AT KALPAKKAM:CALCULATED REFLECTOR BeO TEMPERATURE DEPENDENCE OF K-eff OF KAMINI ~5.3pcm/Deg. C (BOTH DENSITY AND CROSS SECTIONS WERE ACCOUNTED)

Temperature

Density(g/cc) Keff Std. deviation

∆K

293 2.9299 0.99007 0.00025 0

600 2.9058 1.00131 0.00025 0.01124(11.2mk)

800 2.8903 1.00648 0.00025 0.01641(16.4mk)

1200 2.8598 1.01385 0.00025 0.02378(23.8mk)

We understand why the reflectivity worth goes up with temperature in the case of KAMINI (Next slide).

69 group plots, Scattering cross sections Be in BeO (XnWLUP package )

We understand why the reflectivity worth goes up with temperature in the case of KAMINI

KAMINI is a highly reflected system. Massive BeO as a Reflector in KAMINI contributes as much as 0.45 to keff of 1.000 (as estimated by Radha and Reddy)

Temperature increase increases the scattering cross sections as illustrated in WLUP multigroup comparison graphs and as in ENDF/B evaluated data.

The density effect due to increase of temperature reduces reactivity, as expected but this is not a dominant factor in KAMINI.

In 1986-88 period, our calculations for a fast reactor illustrated that depending on the cross section used for U-233 and Th-232 at that time, the maximum breeding gain shows a variation of nearly factor two between extreme values.S. Ganesan, M. M. Ramanadhan, V. Gopalakrishnan, P.V.K. Menon and S. M. Lee, "New Results of the Use of Recent Nuclear Data Files for 233U and 232Th on Doubling Time Characteristics for a Typical FBR," pp III.1 to III.8 in the Proceedings of the International Conference on the Physics of Reactors, Operation, Design and Computation, Marseille, France, 23-27 April 1990, Societe Francaise l'energie nucleaire (SFEN).

•The interesting results of large discrepancies obtained by the author in the calculated criticality properties of minor actinides, such as, 241Am, 243Am, 231Pa, 232U and 233Pa shed light on the inadequacy of nuclear data of these minor actinides in the fast energy region.

•The minor actinides nuclear data are crucial also in international formulation of radioactive transport regulations.

10-January 2006 TSC PRESENTATION

10-January 2006 TSC PRESENTATION

An Example: Comparison of calculated k, the infinite medium

multiplication factor of 243Am and critical mass

Data file used k Critical radius /mass Remarks

ENDF/B-V Not available (14.0203) 157kg MCNP4A Ref. 5

JENDL-3.2 1.44929 .00113

17.20/291kg Present calculations

JEF-2.2 1.59128 .00116

15.45/210kg Present calculations

ENDF/B-VI.6 1.68713 .00117

13.61/144kg Present calculations

ENDF/B-IV 1.926 22.89cm / 596.24kg Density used =11.87g/ccRefs. 6-9

Not available (31.71405cm) / 1824kg SCALE4.3 code systemDensity=13.6g/cc. Ref. 5, 10

1.11338 .00087

36cm / 2668.66kg Present calculations

ANS STANDARD Not available (13.9cm) / 153kg

ANS STANDARD Not available (9.823255cm)/ 54kg

Criticality property of 231Pa.

Description Earlier BARC Study19

Present Study MCNP).based on JENDL-3.2:

keff of a sphere of radius of 13.61 cm using Monte Carlo method (MCNP)

1.000 (DTF)

0.6014 0.0034

Infinite medium multiplication factor, k

2.199 (DTF)

0.9727 0.00114

ENDF/B-VI (Rev. 5) k ~ 0.94.

The ANSI critical mass value was not based upon any ENDF/B file. It was 750 kg based on three-group diffusion theory calculation. Corresponds to a k of ~1.2

Infinite Medium multiplication factor, k,

233Pa USING JENDL-2

S. Ganesan et al. / Annals of Nuclear Energy 29 (2002) 1085–1104

In the case of thorium fuel, only the 232Th isotope is considered to be naturally present and assumed to be 100% abundant. However, it has been stated in the literature that the isotopic composition of thorium ores varies considerably, depending on the amount of associated uranium and its effect in producing an admixture of 230Th daughter. A survey by (Figgins and Kirby, 1966), indicated that the ionium content of thorium ores can vary from almost zero up to as much as 11.6%. This report is referred to on p. 87 in a book by (Stewart, 1985). In theory, if a uranium ore has an extremely high U/Th atom ratio (on the order of 10,000) and is old enough (more than 350,000 years), the isotopic abundance of 230Th could be greater than 10% as mentioned by Professor Chih-An Huh (Huh, 1999). In view of the hard gamma radiation from the daughters of 232U, it is necessary to prefer thorium ores with low 230Th content.

That a presence of 232U may give a complete proliferation resistant mechanism has not been unanimously accepted in the literature. For instance, according to (Rickard and Dahlberg, 1978; Ragheb and Maynard,1980) one can make the 232U problem disappear, defeating non-proliferation purposes, by deactivating the 233U fuel containing 232U by frequently removing 228Th which is the first daughter of 232U, by chemical separation, and re-fabricating 233U fuel rapidly before the increase in the daughters of 232U creates a problem. Generally, it has been assumed that the thorium fuel cycle is proliferation resistant with the formation of the 232U whose daughter products after five successive alphadecays are hard-gamma emitters.

S. Ganesan et al. / Annals of Nuclear Energy 29 (2002) 1085–1104

However, in the thorium fuel cycle, another factor namely, the 233Pa isotope, has raised (Bowman, 1997) some weapon-proliferation concerns. In a recent study by (Bowman, 1997) on the accelerator driven transmutation technology (ADTT) project, it is mentioned that, in theory, a sizable (11 kg) fraction of the estimated inventory of 22 kg of 233Pa could be extracted from the molten salt blanket of thorium, using heroic measures, to produce pure weapon grade 233U. In the ADTT concept (Bowman, 1997, page. 149), it is interesting to note (within quotes; in italics, not edited): ‘‘With the removal of 11 kg of 233Pa, the thermal power level would have decreasedby a factor of three and the net electric power into the commercial grid by a factor of about five while the accelerator power would have remained the same. The power level would recover over a period of several months but the inconsistency between the accelerator power and the electric power output would be readily observed by infrared mapping from satellites or by other means.’’ According to (Wilson and Ainsworth, 2000), 233U requires the same level of safeguards oversight and physical protection as does plutonium.

S. Ganesan et al. / Annals of Nuclear Energy 29 (2002) 1085–1104

S. Ganesan et al. / Annals of Nuclear Energy 29 (2002) 1085–1104

S. Ganesan et al. / Annals of Nuclear Energy 29 (2002) 1085–1104

Reactor Design physics is incomplete without nuclear data programme and critical facilities

How did the French do it?

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