MANAGEMENT OF RBMK-1500 SPENT FUELAT SHUTDOWN IGNALINA NPP

Ernestas NARKUNAS, Arturas SMAIZYS, Povilas POSKASLithuanian Energy Institute (LEI),Nuclear Engineering Laboratory

Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely

INTERNATIONAL ATOMIC ENERGY AGENCY

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ There is one NPP in Lithuania – Ignalina NPP;

➢ Ignalina NPP contains two RBMK-1500 reactors (Unit 1 and 2)Photos from www.iae.lt

Unit 1 was commissioned in1983 and went into the final shutdown in 2004 12 31 (app. 21 year of operation);

Unit 2 was commissioned in 1987 and went into the final shutdown in 2009 12 31 (app. 23 years of operation);

Introduction

The design lifetime of each Unit was 30 years

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ By design it was foreseen to send the spent nuclear fuel (SNF) of Ignalina NPP forreprocessing to the facilities in former Soviet Union;

➢ After the collapse of Soviet Union and restitution of the Independence of Lithuania in 1990, this became not an option;

➢ It was decided to use passive dry type storage of SNF in storage casks in special facility until the decision on ultimate SNF management will be made;

➢ In compliance with the protocol of Lithuania’s European Union accession, Unit 1 of Ignalina NPP was permanently shut down in the end of 2004, while Unit 2 was shut down in the end of 2009. In total, app. 22 000 pcs. of spent fuel assemblies (SFAs) were generated per operation of both Units;

➢ Currently, there are two spent fuel storage facilities at Ignalina NPP for dry interim storage of all generated SNF and deep geological disposal of SNF is considered as main ultimate SNF management option

Introduction (2)

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ Nuclear fuel with different initial enrichment of U-235 ranging from 2.0% to 2.8%,without and with erbium absorber was used at Ignalina NPP

Amount of generated SNF at Ignalina NPP(June 8, 2018)

SNF at Ignalina NPP

2.0% enrich.64%

2.1% enrich.2%

2.4% enrich.15%

2.6% enrich.9%

2.8% enrich.10%

Location Number of SFAs

Unit 1 reactor 0

Unit 2 reactor 0

Unit 1 storage pools 4445

Unit 2 storage pools 6044

“Existing” dry SFSF 6016

“New” dry ISFSF 5066

TOTAL: 21571** 600–700 pcs. of total number of SFAs are (are expected to be) defective

Distribution of SNF according to initial enrichment

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ Typical burnup varies from 19 to 29 MWd/kgU;

➢ Uranium mass in FA: ~111 kg;

➢ Overall mass of FA: ~185 kg

RBMK-1500 fuel assembly

1 – extension rod, 2 – upper fuel bundle (half fuel assembly); 3 – lower fuel bundle (half fuel assembly); 4 – central rod; 5 – fuel rod

➢ At-reactor storage:

o Unit 1 – SFAs in pools (reactor defueled, last SFA removed in 2009);

o Unit 2 – SFAs in pools (reactor defueled, last SFA removed in 2018)

➢ “Existing” dry Spent Fuel Storage Facility (SFSF):

o Facility is “filled” (place for up to 120 pcs. of casks.):

▪ 20 CASTOR®RBMK-1500 casks;

▪ 98 CONSTOR®RBMK-1500 casks

➢ “New” dry Intermediate Spent Fuel Storage Facility (ISFSF):

o Facility is in operation (place for up to 202 pcs. of casks):

▪ 56 CONSTOR®RBMK-1500/M2 casks (June 8, 2018)

Current status of SNF storage at Ignalina NPP

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

Layout of SNF storage facilities at Ignalina NPP

Existing SFSF

New ISFSF

Reactor Units 1 and 2

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ Storage Pools are located in the samebuilding as Reactor, above the groundlevel;

➢ Building itself serves as a partialcontainment;

➢ Reactor Hall and Storage Pools Hall areseparated by concrete wall;

➢ 4445 SFAs in Unit 1 pools (June 8, 2018);

➢ 6044 SFAs in Unit 2 pools (June 8, 2018)

At-reactor storage

Ground level

Refueling Machine

Reactor

Storage Pools Hall

Unloaded from the reactor core SFAs are transferred into the storage at-reactor pools where they are cooled for at least 1 year;

After that, SFAs are cut into the two fuel bundles and loaded into the special baskets (32M type) which afterwards are placed in pools for the wet storage

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

At-reactor storage (2)

➢ SFAs storage at-reactor pools

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

32M basketcontaining 102 half-SFAs

SFAUpper half-SFA

Lower half-SFA

SFAs (uncut)

Half-SFAs (cut SFAs)

Extension rod

➢ First cask with SNF was transferred in1999;

➢ CASTOR®RBMK-1500 – GNB designductile cast iron dual purpose cask(DPC) for SNF transportation (on site)and interim storage;

➢ CONSTOR®RBMK-1500 – GNB designmetal-concrete dual purpose cask(DPC) for SNF transportation (on site)and interim storage;

➢ Both types of casks accommodate 1basket (32M type) containing 51 SFA(102 half-SFAs)

“Existing” dry SFSF

After at least of 5 years storage of SNF at-reactor pools, baskets with SNF were loaded into the CASTOR®RBMK-1500 or CONSTOR®RBMK-1500 casks which were transferred to the SFSF;

SFSF is “open” type facility having concrete foundation slab and walls, designed to store up to 20 CASTOR®RBMK-1500 and 100 CONSTOR®RBMK-1500 casks;

SFSF is “filled” and is loaded with 20 CASTOR®RBMK-1500 and 98 CONSTOR®RBMK-1500 casks(i.e. 6016 SFAs in total)

Photos from www.iae.lt

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

“Existing” dry SFSF (2)

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ SFAs storage in CASTOR®RBMK-1500 and CONSTOR®RBMK-1500 casks at “existing” dry SFSF

CONSTOR®RBMK-1500 CASTOR®RBMK-1500

“New” dry ISFSF

After at least of 5 years storage of SNF at-reactor pools, SNF could be loaded into the new CONSTOR®RBMK1500/M2 casks and transferred to the ISFSF;

ISFSF is “closed” type facility having concrete foundation slab, walls and roof, designed to store up to 202 CONSTOR®RBMK-1500/M2 casks (all remaining (~16 000) SFAs of Ignalina NPP);

ISFSF is in operation and is loaded with 56 CONSTOR®RBMK-1500/M2 casks for June 8, 2018(i.e. 5066 SFAs in total)

Photos from www.iae.lt

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ First cask with SNF was transferred in2016;

➢ CONSTOR®RBMK-1500/M2 – GNSdesign metal-concrete dual purposecask (DPC) for SNF transportation(on site) and interim storage;

➢ It accommodates 2 baskets (32Mtype basket in centre and ring basketsurrounding it) containing up to 91regular SFA in total;

➢ Cask could also be loaded withspecial basket designed to storedamaged SFAs

“New” dry ISFSF (2)

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

➢ SFAs storage in CONSTOR®RBMK-1500/M2 casks at “new” dry ISFSF

CONSTOR®RBMK-1500/M2

Ultimate SNF management in Lithuania

➢ No final decision of ultimate SNF management is made, however disposal is main option;➢ Currently, SNF will be stored at the interim dry SFSFs at Ignalina NPP for at least 50 years;➢ According to former Lithuanian “RW Management Strategy”, the possibilities of ultimate SNF

management options were:(1) deep geological repository in Lithuania;(2) regional deep geological repository of several European Union member states;(3) transfer of SNF to countries that own proper facilities and take responsibility for SNF

➢ Based on current “Development Programme for RW Management” which was prepared in 2015 according to EU Directive 2011/70/Euratom, deep geological repository in Lithuania is considered as main ultimate SNF management option

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

Main stages for construction of deep geological repository

Planning and preliminary investigations

Selection of site suitable for the repository and comprehensive studies (geological, hydrological, geochemical, etc.)

Investigations, designing and safety analyses (overlapping “stage”)

Construction of facility for SNF placement into canisters

Construction of the repository facilities (at surface)

Construction of the repository (underground works)

Target date to have deep geological repository in operation – 2066

➢ Based on the investigations of Lithuanian geological structure, crystalline rock and clay formations were identified as possible for deep geological repository and where analysed;

➢ Repository concept (considered for the generic studies) in crystalline rock is based on KBS-3 concept developed by SKB for disposal of SNF in Sweden;

➢ Repository concept (considered for the generic studies) in clay formations is based on Swiss concept developed by NAGRA for disposal of SNF in Switzerland

IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites, Including Those to be Shut Down Prematurely, Vienna, Austria, 11–13 Julne 2018

Ultimate SNF management in Lithuania (2)

Ignalina NPP

Disposal canister with insert containing 32 half-SFAs

Steel canister for clay formations

Cooper canister for crystalline rock

Dr Ernestas Narkunas

ernestas.narkunas@lei.lt

Thank you for your attention