spent fuel management: current situation in germany€¦ · spent fuel management: current...

Spent Fuel Management:

Current Situation in Germany

Konrad Linnemann

Uwe Herbrich

Frank Wille

Holger Völzke

BAM Federal Institute for Material Research and Testing

IAEA Technical Meeting

“Lessons Learned in Spent Fuel Management”

IAEA Headquarter

Vienna, Austria

08.-10.07.2014

Outline

� Spent fuel situation in Germany

o Phase out decision

o Estimated amount of spent fuel assemblies

o Dual purpose casks

o Extended storage periods

� Spent fuel issues for transport and storage

o Protection goals and requirements

o Fuel rod behavior and assumptions in

− Criticality safety analysis

− Containment assessment

o High burn-up fuel

o Experimental testing

� R & D

� Conclusions

BAM 3.3 Linnemann IAEA Technical Meeting 08.-10.07.2014 2

Spent fuel situation in Germany

Phase out decision in 2011

Until 2011: 17 NPPs (11 PWR + 6 BWR)

Since 2011: 9 NPPs (7 PWR + 2 BWR)

2022: Shut-down of last NPP

Accumulated spent fuel until 31.12.2012:

8,000 Mg HM (+ 6,700 Mg HAW) 53,100 fuel assemblies

Additional:

2,500 Mg HM 6,900 fuel assemblies

Total at 31.12.2022:

10,500 Mg HM (+ 6,700 Mg HAW) 60,000 fuel assemblies

1,000 dual purpose casks in use

5001600 additional dual purpose casks needed



Dry storage concept for spent fuel

� According to Recommendations of German

Waste Management Commission in 2013

� Accident safe dual purpose transport and

storage casks

� Double barrier lid system

� Barrier system permanently monitored

� Valid Type B(U) approval required at

storage placement

o Permanent transportability

� Storage license limited up to 40 years


© GNS


Perspectives

Expiration of some interim storage licenses:

Jülich 30.06.2013 !

Gorleben: 31.12.2034

12 on-site storage facilities: 2042/43

Timeline based on Site Selection Law for Disposal:

Extended storage period will be required!


2016

Site selection

procedure

2023

Site selection for

underground

exploration

2031

Final site

selection

Licensing procedure and

repository construction15 1 20 years

≈ 2050Operation phase

≈ 30 years

(50 casks per year)

2034 2042/2043

Expiration of

interim storage

licenses

At least 40 years

extended interim

storage

≈ 2080

(After only 20 years, transport in preparation)


Dual-purpose casks

� GNS CASTOR

� AREVA TN International

� Storage and transport of high burn-up fuel

possible (up to 65 GWd/tU)

� What are the spent fuel issues assessed

by BAM?


© GNS

Spent fuel issues for storage licensing

Protection goals

� Confinement of radioactive material

� Stable removal of decay heat

� Maintenance of subcriticality

� Avoidance of unnecessary radiation exposure

Requirements for spent fuel

� Fuel assembly without defects or encapsulation of defective fuel

� Prevent systematic cladding failure

o Limitation of cladding tube corrosion

o Compliance of valid stress/strain

(according to Recommendations of German Waste Management Commission in 2013)


Spent fuel issues for transport licensing

Regulatory transport conditions (IAEA test scenarios)

� Routine conditions of transport

o Regular transport

o No incidents

� Normal and accident conditions of

transport

o Impact loads of drop tests

o Thermal load of fire test

o Examples:

− 0.3 m drop onto unyielding target

− 9 m free drop onto unyielding target

+ 1 m puncture drop

+ 30 minutes fire at 800 °C



Interface for criticality safety analysis

� Influence on criticality safety(accident conditions of transport)

o Deformation of fuel assembly

(distances between fuel rods)

o Fuel rod breakage

� evaluation of critical mass of fissile material in cavity

� Limited data

� simplified enveloping approach necessary



Interface for criticality safety analysis (cont’d)

� Assessment by BAM based on:

o Deformation state � fracture points

of fuel assembly

o Amount of released fissile material

per fuel assembly

� Total amount of released fuel in cavity

� Input for criticality safety analysis

(BfS, Federal Office for Radiation Protection)


Source: Papaioannou et al:

Jahrestagung Kerntechnik,

12-14 Mai (2009)


Activity release calculation

� Maximum loss of radioactive contents

specified in transport regulations (SSR-6)

� Fuel rod failure and activity release (normal and accident conditions of transport)

� Cladding breaches lead to:

o Activity release into cask cavity (gas, volatiles, fine fuel particles)

o Increase of cask internal pressure

� Assumption of Failure rates


Fuel rod section

release of:

- fission gas

- volatiles

- fine fuel

particles

fuel

pellets

cladding

cladding

breaches

plenum


Activity release calculation (cont’d)

� Failure rates of fuel rods

o Normal conditions of transport (e.g. 0.3 m drop)

− 3 % for burn-up ≤ 55 GWd/tU (based on NUREG/CR-6487 report)

− 100 % for burn-up ≤ 65 GWd/tU

o Accident conditions of transport (e.g. 9 m drop)

− 100 % for all burn-up (based on NUREG/CR-6487 report)

� Amount of released fissile products in cavity

� Containment analysis based on standard leakage rate


R & D

� Long-term performance tests for extended storage at BAM

o Metal seal relaxation and creep

o Leakage rate measurement concerning:

− Elastomer auxiliary seal degradation

− Helium contamination

o Degradation of polymer components for neutron shielding

� Investigation of spent fuel assemblies in cooperation with:

o Sandia National Labs (Albuquerque, USA)

o Institute for Transuranium Elements (Karlsruhe, Germany)


Conclusions

� Phase-out decision and complete restart of repository siting

procedure in Germany

o Storage period of more than 40 years will be expected

� Dual purpose casks in Germany

o Valid Type B(U) approval required at storage placement

� Spent fuel issues for transport and storage

o General storage requirements

o Criticality safety analysis

o Containment assessment

o Limited data of fuel behavior

� R&D


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