ФГУП «Горно-химический комбинат»

Experience of the FSUE “MCC” in ManagingHigh Burnup Spent Nuclear Fuel from NPPs

State Corporation Atomic Energy “Rosatom”

FSUE “Mining and Chemical Combine”

VVER-1000 SNF Suppliers of the FSUE “MCC”VVER-1000 SNF Suppliers of the FSUE “MCC”

2

Balakovo

Rostov

Novovoronezh

Yuzhnoukrainskaya

1

2

3

5

4

6

8

Kalinin

Khmelnitsk

7 Rovno

“Kozloduy”

Russian NPPs:

Ukrainian NPPs:

Bulgarian NPP:

VVER-1000 SNF is shipped from a NPP to the FSUE “MCC” on special TK-13-type rail cars in certified TUK-13 shipping casks containing 12 SNFAs

3

Means of SNF Transportation Means of SNF Transportation

TK-13 rail car characteristics:- Rail car mass – up to 60 t- Carrying capacity – not less than 110 t- Wheel track – 1,520 mm- Length – 19 m- Number of axes – from 8 to 12- Position of the rail car – horizontal.

4

TUK-13 CharacteristicsTUK-13 Characteristics

Cask type TK-13 TK-13/1

Destination transportation

Capacity, number of SFAs 12

Initial fuel enrichment (U-235, max.%) Not greater than 4.95

Fuel burnup, GWD/Ut Not greater than 58

Decay heat per TUK, kW Not greater than 20

SNF cooling before loading into the cask, yrs Not less than 3

Coolant in the cask Atmospheric air

Loaded TUK mass, t 116 113

Cask body material06N2M steel,

12Cr18Ni10Ti steel lining

12Cr18Ni10Ti steel

Neutron protection Liquid

Neutron protection material Antifreeze (grade 65) or cooling liquid (OZh-65)

Number of sealing lids 1

5

Integrated Technological Complexfor Centralized SNF Management

Integrated Technological Complexfor Centralized SNF Management

Wet Storage for VVER-1000 SNF Pilot

Demonstration Center

Dry Storage for VVER-1000 SNF

Dry Storage forRBMK-1000 SNF

Dry Storage for RBMK-1000 SNF

Reference Cask Area

6

Wet Storage Facility for VVER-1000 SNFWet Storage Facility for VVER-1000 SNF

Seismic stability: up to 8

SNF storage capacity: greater than 8000 t

High reliable safe storage systems for SNF

Capability to transfer SNFAs for dry storage

Capability to transfer SNFAs for reprocessing at PDC

Capability to store SNF from new nuclear fuel cycles with greater thermal and radiation characteristics(5% U-235, up to 58 GWD/U tons)

After modification, the period of its operation has been extended until 2045.

7

Dry Air-cooled Storage for RBMK-1000 SNFDry Air-cooled Storage for RBMK-1000 SNF

Capability to withstand fall of a 5-t airplane;Capability to withstand an earthquake measuring 9.6; Design life period of 50 years, which may be extendedup to 100 years;Passive cooling system for SNFAs;Comprehensive safety monitoring.

Safe storage of SNF is ensured by

8

Putting VVER-1000 SNFAsin Wet Storage

Putting VVER-1000 SNFAsin Wet Storage

Cask cooling and unloading from

the rail car

SNFAs reloading from the cask into storage baskets

SNFAs shipping

Wet storage for SNFAs

Empty cask preparation

StorageTransportation

NPP

9

Water-cooled SNFA Storage Facility

(kHOT-1)

SNFAs reloading from the basket into a one-

seat hoist

KhOT-2

SNFAs reloading from the hoist into a four-seat storage canister

Canister transfer for storage

Canister sealing.Inspection of welding

quality.KhOT-1

Putting SNFAs in long-term storage

Putting VVER-1000 SNFAs in Dry StoragePutting VVER-1000 SNFAs in Dry Storage

10

Range of VVER-1000 Fuel AssembliesRange of VVER-1000 Fuel Assemblies

Average initial enrichment(in U-235, %) Design burn-up depth, GWD/Ut

3 50

3.53 50

3.9 50

4.3 56

4.67 68

4.81 68

11

Residual Heat Generated by SNFResidual Heat Generated by SNF

0

2

4

6

8

10

12

14

16

18

20

1 2 3 4 5 6 7 8 9 10

Res

idua

l hea

t, kW

Ut

Cool-down after discharging from the reactor, yrs

40

50

58

68

Burn-up depth, GWD/Ut

The main factor having an effect on safety of thermal conditions in the Wet Storage Facility is that the pool cooling system is capable of removing residual heat from all the SNFAs stored in KHOT-1 compartments. In routine storage conditions the cooling system must provide for an allowed water temperature in the storage compartments. When SNFAs are in water whose temperature is maintained by the cooling system, the values of decay heat generated by the SNFAs located under water are of no importance, and what matters is the value of summary decay heat specified by the cooling system design. Therefore, an analysis was conducted concerning summary decay heat to be generated by the SNFAs located in the compartments with due regard for incoming ones with an initial enrichment of up to 5.00% (mass) and a fuel burnup of up to 58 GWD/Ut.

To determine the conditions ensuring the thermal design parameters, a design analysis was performed to determine the change in summary decay heat in the KHOT-1 cooling pools depending on time. The limiting factor in filling up the storage facility is its capacity or summary decay heat from stored SNF, which must not exceed heat removal capability of the cooling system.

Calculations considered options both of complete filling of KHOT-1 without SNFA unloading, and those when income occurs simultaneously with SNFAs being unloaded and transferred from the Wet Storage Facility to KHOT-2 (the Dry Storage Facility) and to the PDC for reprocessing.

12

Ensuring Thermal Conditions in the Wet Storage FacilityHousing SNF with a Greater Enrichment and Burnup

Ensuring Thermal Conditions in the Wet Storage FacilityHousing SNF with a Greater Enrichment and Burnup

13

1 – Summary SNFAs decay heat, no SNFAs unloaded2 – Summary SNFAs decay heat, with 500 SNFAs/yr unloaded3 – Summary SNFAs decay heat, with 1000 SNFAs/yr unloaded4 – Summary SNFAs decay heat, with 1500 SNFAs/yr unloaded

Summary Decay Heat Generated in the Options Consideredfor the Completely Filled Wet Storage

Summary Decay Heat Generated in the Options Consideredfor the Completely Filled Wet Storage

With due regard for decrease in heat generated by incoming SNFAs with a greater burn-up and decay heat, the average decay heat per pool is 1.65 kW/SNFA. When the storage compartment is completely filled with SNFAs placed in an established order, summary decay heat will not exceed limiting values even at the average decay heat per assembly of 1.71 kW/SNFAs.

14

Ensuring Radiation Safety of the Wet Storage FacilityHousing SNF with a Greater Enrichment and BurnupEnsuring Radiation Safety of the Wet Storage FacilityHousing SNF with a Greater Enrichment and Burnup

Neutron and gamma radiation values for the SNFAs considered were derived by computation with the use of RADIONUCLID software for the mode of fuel burning in the campaign, which corresponds tothe fuel cycle. To calculate levels of neutron and gamma radiation beyond radiation protection of the storage compartments, the MCNP-4b code was used with the recommended DLC-189 library of nuclear physics constants based on ENDF/B files.

Calculation point beyond protection Protective composition

Radiation level, μSv/hr

The exterior wall of the building Water + concrete 0.0001Semi-attended areas around the storage compartments Water + concrete 0.37

Permanently manned areas Water + concrete 0.007

A pool area above the slit-type floor (above storage baskets of the compartment)

Water layer above a fuel column of a SNFA 0.0003

An area above the slit-type floor(one basket is lifted for 30 cm while being transferred)

Water layer above a fuel column of a SNFA 0.00002

Inside an empty compartment (irradiation from two surrounding compartments) Water + concrete 98

Outside the transfer passageway(from one basket) Water + concrete 0.044

Outside the unloading compartment forshipping casks (from one basket) Water + concrete 0.003

15

Safety Assessment Results for the Wet Storage Facility Housing SNF with a Greater Enrichment and Burnup

Safety Assessment Results for the Wet Storage Facility Housing SNF with a Greater Enrichment and Burnup

The thermal conditions of the storage facility, with due regard for an yearly income of VVER-1000 SNFAs with an initial enrichment in uranium-235 of 5 % (mass) and a burnup depth of up to 58 GWD/Ut, ensure non-exceedance of the limiting values for which thermal conditions for SNF were assessed to be safe with the facility being completely filled. Calculations showed that in routine operating conditions at a pool water temperature of +50°С being maintained by the cooling system, boiling of SNFA rods with a decay heat of up to 3 kW is impossible.

Radiation environment in the storage rooms and beyond the facility in routine operating conditions and in design accidents meet the radiation safety requirements set forth in existing regulatory documents. The maximum SNF radiation exposure on personnel occurs while repair work in a drained compartment of the storage facility. In this event a radiation level in place lets repairmen work with no significant restraints on the working time. The maximum level of volumetric activity in the storage rooms even in case of ventilation failure will not exceed an allowed volumetric activity and will be several times less than a specified reference level. There is no need for any upgrading the storage facility in regards to radiation protection and additional radiation safety assurance.

Given the existing layout of the basket placement, nuclear safety in handling 16-seat 02H-type storage baskets is provided for by loading with VVER-1000 SNFAs with an initial enrichment in uranium-235 of up to 5 % (mass) and a fuel burnup of up to 58 GWD/Ut.

16

Modifying the Wet Storage In Preparation forExtending its Operating Period

Modifying the Wet Storage In Preparation forExtending its Operating Period

Modification (2008-2011): Enhanced seismic stability of

the storage facility: the building structures were reinforced, the roof covering was lightened.

One hoist was upgraded and three others – replaced.

The cooling system throughput and reliability were increased.

Additional storage compartments were created.

12-seat storage baskets were replaced with those for 16 seats.

Initial Design: Initial enrichment in uranium-235 –

up to 4.4 % (mass) Fuel burnup –

up to 50 GWD/Ut Average decay heat –

up to 1.7 kW per SNFA Cool-down after discharging from the

reactor – not less than 3 years In 2015 – 30 operating years

Existing characteristics: Initial enrichment in uranium-235 –

up to 5 % (mass) Fuel burnup –

up to 58 GWD/Ut Average decay heat – up to 2 kW

per SNFA Cool-down after discharging from

the reactor – not less than 6 years Design lifetime extended until

2045.

17

Promising TUK Family (Series 137) Developed bythe FSUE “RFNC-VNIIEF” for SNF Removal to the FSUE “MCC”

Promising TUK Family (Series 137) Developed bythe FSUE “RFNC-VNIIEF” for SNF Removal to the FSUE “MCC”

• A certificate was granted for using TUK-137D and TUK-137T for VVER-1000/1200 SNFAs.

• As for its weight and dimensional characteristics, TUK-137Tis very similar to TUK-13, which allows it to be involved in the existing fuel handling flow charts almost without modifications.

• The in-process tests performed with TUK-137D in the Wet Storage Facility of the FSUE “MCC” proved TUK-137D suitability for fuel handling activities.

• In 2019 TUK-137D is planned to bethermophysically tested to get claimed TUK characteristics and used computational models confirmed.

Present-day TUK-13 and Promising TUK137D.Specification Comparison

Present-day TUK-13 and Promising TUK137D.Specification Comparison

18

TUK-13 TUK-137D

Characteristics TUK-13 TUK-137D

Number of SNFAs 12 20

Fuel burnup, max. GWD/Ut 58 70

Summary maximum decayheat per TUK, kW 20 40

Maximum enrichment in uranium-235, % (mass) 4.95 5.0

Package mass, t 113 119

TUK mass (w/o SNFAs) 104 103

Maximum height of a fuel column, in SNFAs, mm 3,680 3,730

19

Pilot Demonstration Center for SNF ReprocessingBased on Innovative Technologies

Pilot Demonstration Center for SNF ReprocessingBased on Innovative Technologies

At present as part of the work for improving VVER-1000 SNF reprocessing modes, the start-up PDC complex completed pilot SNFA reprocessing, which confirmed feasibility of the Generation III+ Plant process solutions selected for the PDC.

The PDC’s raw material for time while Center improves the technologies in order to derive input data for creation of a large-scale reprocessing plant is VVER-1000 SNF with a burnup of not greater than 50 GWD/Ut and a cooling period of not less than 7 years.

Pilot Demonstration Center for SNF ReprocessingBased on Innovation Technologies

Pilot Demonstration Center for SNF ReprocessingBased on Innovation Technologies

Innovation solutions:

The used processes are those with no low-active wastes (tritium) discharge in environment

Further implementation:

2021 – putting the PDC in operation as a full-fledged facility (250 SNF tons a year)

SNF reprocessing for: VVER-1000, HEU SNF, BN-800, REMIX, SNF of foreign origin.

20

Minimization of technological processes;HAW amount reductions to 0.1m3/SNF t, (an eight-fold reduction compared to similar facilities)

21

ConclusionConclusion

The FSUE “MCC” complex has significant storage capabilities, which makes it possible to provide safe operation of both the

Russian, and foreign NPPs running VVER-1000/1200 reactors, and also gives an opportunity of further reprocessing of spent nuclear

fuel.