r. pampin euratom/ukaea fusion association

Study on recycling of fusion activated materials:Study on recycling of fusion activated materials:

Identify activation levels and decay time Identify activation levels and decay time requirements of irradiated materialrequirements of irradiated material

(deliverable 3)(deliverable 3)

R. PampinR. Pampin

EURATOM/UKAEA Fusion AssociationEURATOM/UKAEA Fusion Association

TW5-TSW-001&002 final meeting TW5-TSW-001&002 final meeting Culham Science Centre, October 2006Culham Science Centre, October 2006

TW5-TSW-001 final meeting, Culham Science Centre, October 2006 2/17

BackgroundBackground

European Fusion Programme strategy for fusion irradiated waste:

Release from regulatory control mildly activated material, usually lifetime, bulky, outer components: TFC, VV, LTS.

Recycle within the nuclear industry (fission/fusion) the rest.

PPCS radioactive waste results: all material cleared/recycled within 100 years, but:

Release criteria: out-of-date IAEA clearance levels (1996).

Lack of detail in the models (e.g. outer components).

Inadequate modelling of particular materials (e.g. LiPb).

Recycling criteria based on radiological parameters only, which were imprecise and over-conservative.



IAEA 1996/2004 clearance levels: many changes affect fusion-relevant radionuclides (e.g. 30-fold decrease in Ni-63 level).

0

1

2

3

4

5

6

7

8

9

10

11

12

0 50 100 150 200 250mass number (A)

log

(200

4 le

vel)

-5

-4

-3

-2

-1

0

1

2

3

0 50 100 150 200 250mass number (A)

log

(200

4/19

96)

TW5-TSW-002 D1 report on implications, TW5-TSW-001 D3 report on specific effects on PPCS-AB.



PPCS recycling criteria: some sensible for certain waste streams following certain routes (e.g. re-melting of steels); “complex recycling” limit is:

(a) noticeably over-conservative and

(b) uncertain: depends on route followed !

waste categorisation criteria contact dose (mSv/h)

decay heat (W/m3)

CI

Permanent disposal (PDW) > 20 > 10

Complex recycling (CRM) 2 – 20 1 – 10

Simple recycling (SRM):

remote

hands-on

< 2

< 10-2

< 1

< 1

Clearance < 1


Scope and objectivesScope and objectives

To review and update PPCS work using:

Up-to-date international clearance levels: IAEA 2004.

Up-to-date nuclear data: EAF 2005.

Practical feasibility criteria: findings of this task.

More accurate modelling methodology (e.g. LiPb flow) and increased level of detail (e.g. TFC and breeder materials).

With the aim of:

Determining more realistic amounts and activation features of the material inventory.

Identifying interim decay times required during recycling.

Identifying potential for (a) reduction of waste, and (b) simplification of processes.


Material inventoryMaterial inventory

ID category PPCS model materials phase* 1a ferritic-martensitic steels AB, B RAFM eurofer operation and decommission 1b austenitic steels and alloys AB, B 316ss, incoloy decommission 2a tungsten-rich alloys AB, B armour, divertor plates operation and decommission 2b tungsten carbide AB WC decommission 3 lithium lead AB LiPb operation and decommission 4 ceramics B Be, Li4SiO4 operation and decommission 5 zirconium hydride B ZrH1.7 decommission 6 others AB, B epoxy-glass, SC cable decommission

PPCS-AB waste

0

20000

40000

60000

80000

100000

120000

140000

1a 1b 2a 2b 3 4 5 6 totalmaterial category

tonn

es

PPCS-AB operation

PPCS-AB decommission

PPCS-B waste

0

10000

20000

30000

40000

50000

60000


ton

ne

s

PPCS-B operation

PPCS-B decommission

PPCS-AB based on the HCLL blanket concept, PPCS-B based on the HCPB blanket concept.


Industry experienceIndustry experience

Distinction between recycling and refurbishment:

Refurbishment: little or no processing, on-site, immediate or early reuse in the fusion plant (e.g. LiPb, ceramics).

Recycling: greater processing, off-site, later reuse in the nuclear industry in general.

Recycling strategies in the industry exist for:

Very low activity: fabrication of simple components.

Very high activity: de-activation and re-fabrication of internals.

Recycling routes envisaged for all PPCS-AB and PPCS-B materials (TW5-TSW-001 B report).


clearance index 1specific activity Bq/kg (b+g) 400 4.0E+04 1.2E+07contact dose rate mSv/h 0.001 0.01 2 20 100 10000 1.0E+07decay heat rate W/m3 1 10 100 2000 10000 ????

IAEA-UK [1], [2], [3] NAW VLLW LLW ILW HLW

SEAFP, PPCS [4] NAW SRM CRM PDW

new proposal [5] NAW HOR shielded-HOR RHR

clearance yes no

handling [5] HOR shielded-HOR? increasing RH demands --------------------------------> hot cell limit

cooling [?] no cooling increasing cooling demands --------------------------> hot cell limit

transport [6] unshielded increasing shielding -------> special transport? transport limit

[1] IAEA Safety Standards Series, RS-G-1.7 (2004)[2] IAEA Safety Series 11-G-1.1 (1995)[3] C. Bayliss, Nuclear Decomissioning and Waste Management, UKAEA-Elsevier[4] M. Zucchetti et al., Fusion Engineering and Design[5] L. Ooms, TW5-TSW-001 D2 report[6] IAEA Safety Standards, TS-R-1 (2005)

Radiological levelsRadiological levels

Use radiological levels to ascertain storage times needed for the activity to decay to levels facilitating recycling processes:

Clearance: C.I.Lower RH needs: contact dose rate.Lower cooling needs: decay heat rate.Easier transport: ?


Computational tools and modelsComputational tools and models

1.E+08

1.E+09

1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

1.E+15

1.E+16

1.E+17

1.E+18

1.E+19

1.E-08 1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02

energy (MeV)

flux

pe

r u

nit

leth

arg

y

TFC (IB)VVLTSHTSBLANKET BACKBLANKET FRONTBLANKET FWARMOUR


Results: clearanceResults: clearance

New IAEA levels increased amounts of material to be recycled: OB VV and IB TFC.

Time scales: few years OB, few decades IB.

Segregation alleviates this.

PM-AB clearance index - outboard

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

0.1 1 10 100 1000time (y)

clea

ranc

e in

dex

TFC 2004

TFC 1996

VV 2004

VV 1996

LTS 2004

LTS 1996

0

5000

10000

15000

20000

25000

30000

TFC OB TFC IB VV OB VV IB total

IAEA 1996

IAEA 2004

IAEA 2004 with segregation

PM-AB clearance index (2004) - inboard

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

0.1 1 10 100 1000time (y)

clea

ranc

e in

dex

TFC 316ss frontTFC 316ss midTFC 316ss backTFC cableTFC incoloyTFC epoxyaverage


Results: refurbishmentResults: refurbishment

Refurbishment of LiPb is possible and reduces considerably the amount of operational waste (from 124000 to 97000 tonnes).

PPCS-B ceramic breeder and other materials also possible, but much lower impact strategic value?

PPCS-AB waste

0

20000

40000

60000

80000

100000

120000

140000


tonn

es

PPCS-AB operation

PPCS-AB decommission

PM-AB contact dose rates - outboard

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

0.1 1 10 100 1000time (y)

cont

act d

ose

rate

(Sv/

h)

54321


Results: recyclingResults: recycling

PPCS-AB results:

Ex-vessel: most materials, individually or as TFC, VV and LTS, show contact dose rates < 2 mSv/h (earlier OB than IB).

Ex-vessel: many of these show < 0.01 mSv/h after suitable decay time (few years OB, several decades IB).

In-vessel: poloidal variation is negligible.

In-vessel: all Eurofer and LTS neutron shield (WC) show contact dose rates < 2 mSv/h after ~75 years.

In-vessel: LiPb breeder and W armour still exceed 2 mSv/h after 100 years:

Dominant nuclides arise from Pb and W isotopes, hence impurity control not very useful in this case! isotopic separation needed.



1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

0.1 1 10 100 1000time (y)

cont

act d

ose

rate

(Sv/

h)

ppcs W 5 fpy

pure W 5 fpy


1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

0.1 1 10 100 1000time (y)

cont

act d

ose

rate

(Sv/

h) ppcs lipb 30 fpy

pure Pb 30 fpy

Results: recycling - impurities Results: recycling - impurities

W and LiPb PPCS specifications contain many impurities: (a) manufacturer limits, (b) detection limits.

Co, Ni, Nb, Mo, Eu, Sm, Gd, Tb, Pt, Ir, Pb, U, Th, Bi, Ag, Cd, Ba, Tl, Co, Nb


PMB contact dose rates - outboard

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

0 1 10 100 1000time (y)

cont

act d

ose

rate

(Sv/

h) ppcs li4sio4pure li4sio4ppcs be

Results: recycling - impuritiesResults: recycling - impurities

PPCS-B results:

In-vessel: again, (nearly) all Eurofer and LTS neutron shield (ZrH) show < 2 mSv/h in ~75 years.

In-vessel: Li4SiO4, Be and W armour, however, do not meet this target Li4SiO4 and Be dose entirely due to impurities:

Co, Ni, Nb, Mo, Eu, Sm, Gd, Tb, Pt, Ir, Pb, U, Th, Bi, Ag,

Cd, Ba, Tl, Co, Nb


Results: decay timesResults: decay times

component / constituent / material 104 mSv/h 100 mSv/h 2 mSv/h 0.01 mSv/h CI < 1

OB TFC / case rear / 316ss <1d <1d <1d <1d <1d

OB TFC / radial plates / 316ss <1d <1d <1d <1d <1d

OB TFC / case front / 316ss <1d <1d <1d 2y 45y

OB TFC / epoxy-glass / 316ss <1d <1d <1d <1d <1d

OB TFC / conduits / incoloy <1d <1d <1d <1d <1d

OB TFC / cable / SC strand <1d <1d <1d <1d <1d

OB VV / rear wall / 316ss <1d <1d <1d 10y 45y

OB VV / radial plates / 316ss <1d <1d 5y 50y >1000y

OB VV / front wall / 316ss <1d 25y 58y >1000y >1000y

OB LTS / structure / eurofer 180d 25y 50y >1000y >1000y

OB LTS / neutron shield / WC 10d 15y 55y >1000y >1000y

blanket / manifold / eurofer 15y 45y 80y >1000y >1000y

blanket / BZ / eurofer 10y 35y 70y >1000y >1000y

blanket / BZ / LiPb (5 fpy) 120d 15y 90y >1000y >1000y

blanket / BZ / LiPb (30 fpy) 120d 25y >1000y >1000y >1000y

blanket / FW / eurofer 15y 45y 80y >1000y >1000y

blanket / armour / W 5y 45y 500y >1000y >1000y


SummarySummary

Upgrading PPCS work on PPCS-AB and PPCS-B radioactive waste analysis using recent regulations, new nuclear data, improved modelling and realistic recycling scenarios.

Assess clearance/refurbishment/recycling potential and interim decay times.

Results:

new IAEA levels increase amount of material to recycle;

clearance is achieved within few years (OB) or few decades (IB);

most recycling material below 2 mSv/h after ~75y of decay;

are these acceptable time scales?


SummarySummary

Three key issues to optimise fusion recycling strategy by reducing amount of material, secondary wastes and/or radiological levels:

Segregation of materials

Refurbishment

Impurity control

Further work:

Shielding issues, particularly in PPCS-B

Transport requirements?

New categorisation?

Radioactivity build-up due to (a) impurities and (b) reuse.

www.fourmilab.ch/earthscr/


Fusion materials strategy – open


Fusion materials strategy – closed


clearance index 1specific activity Bq/kg (b+g) 400 4.0E+04 1.2E+07contact dose rate mSv/h 0.001 0.01 2 20 100 10000 1.0E+07decay heat rate W/m3 1 10 100 2000 10000 ????

IAEA-UK [1], [2], [3] NAW VLLW LLW ILW HLW

SEAFP, PPCS [4] NAW SRM CRM PDW

new proposal [5] NAW HOR shielded-HOR RHR

clearance yes no

handling [5] HOR shielded-HOR? increasing RH demands --------------------------------> hot cell limit

cooling [?] no cooling increasing cooling demands --------------------------> hot cell limit

transport [6] unshielded increasing shielding -------> special transport? transport limit

[1] IAEA Safety Standards Series, RS-G-1.7 (2004)[2] IAEA Safety Series 11-G-1.1 (1995)[3] C. Bayliss, Nuclear Decomissioning and Waste Management, UKAEA-Elsevier[4] M. Zucchetti et al., Fusion Engineering and Design[5] L. Ooms, TW5-TSW-001 D2 report[6] IAEA Safety Standards, TS-R-1 (2005)

Fusion materials strategy: radiological levels and classification criteria?

– simple transport RHR – complex transport

r. pampin euratom/ukaea fusion association

Documents

recycling routes

recycling processes

recycling strategies

activation levels

complex recycling crm2

simple recycling srm

fusion irradiated waste

ppcsb materials tw5tsw