Transport and Interim Storage of Spent Nuclear Fuel (SNF) in Germany

Frederik Kesting,24.09.2019

Transport and Interim Storage of SNF in Germany

• Nuclear waste management in Germany

• Extended interim storage

• Design approval of transport packages

• Dual purpose casks currently in use

Nuclear waste inventory of Germany

• all new SNF is stored in interim storage facilities or in pools at the NPP

• very last use of MOX in spring 2017 (NPP Emsland)

• 7 nuclear power plants still in operation

• until 2018: in total 1123 casks in interim storage, mostly SNF

• in total 286 casks with nuclear waste from reprocessing plants:• 108 casks with vitrified waste from La Hague (F) are stored in interim storage facility Gorleben.

• 5 casks from Sellafield (UK) and 21 casks from Cellafield (UK) with vitrified waste will be transported toGermany soon.

• 152 casks with waste fromLa Hague (F) will be transported to Germany not before 2030.

Source: BfE: “Statusbericht zur Kernenergienutzung in der Bundesrepublik Deutschland 2018”, urn:nbn:0221-2019081919007, Salzgitter. 08/19

All NPP are going to shut down until 2022!

Since 2005, no reprocessing of SNF!

Dry interim storage in dual purpose casks

Krümmel

BrokdorfBrunsbüttel

Unterweser

Emsland

Philippsburg

Obrigheim

Neckarwestheim

Gundremmingen

Isar

Grafenrheinfeld

Grohnde

Zwischenlager Nord (ZLN)

Biblis

Ahaus

Gorleben

Central interim storagefacility

On-site interim storage facility

Jülich

BfE: competent authority for licensing

interim storage facilities

BGZ: operator of interim storage facilities

Central interim storage facilities:• licenses valid until 2034 (Gorleben), 2036 (Ahaus),

and 2039 (Lubmin, ZLN)

On-site interim storage facilities:• start of operation: 2002 – 2007• licenses valid for 40 years

1123 casks in interim storage

• 607 in on-site facilities

• 516 in centralized facilities

Site selection for nuclear waste repository

• individual steps defined by “Site Selection Act” (5th of May 2017)

• storage in geological formation (salt, crystalline rock, or clay)

• project developer: Bundesgesellschaft für Endlagerung (BGE)

• Role of BfE

• to control the search for a site on behalf of the federal government

• to organize the public participation

site selectionconstructionof

waste repositoryemplacement

2031 2050 ???

Extended interim storage

Expiration of licenses for interim storage: 2034 – 2047

Emplacement of SNF in waste repository: not before 2050

• Extended interim storage and subsequent transportation is unavoidable!

• Applications for extended storage have to fulfill thesame requirements as new applications!

• Periodical safety inspections, including ageing management [2,3]

What questions are arising?

• regulatory aspects: environmental impact assessment, participation of public, engagement by the parliament (German Bundestag)

• all analysis have to be based upon the state of science and technology

• transportation after interim storage / mandatory transport license

Source: In “Zwischenlagerung hoch radioaktiver Abfälle” , Springer 2017: ”Wissenschaftlich-technische und rechtliche Aspekte für Genehmigungsverfahren nach §6 AtG zur Aufbewahrungbestrahlter Kernbrennstoffe über 40 Jahre hinaus”, T. Zeiger, C. Gastl, F. Töpfer, S. Witte, K. Reichel, C. Bunzmann

Design approval of transport casks

Assessment of• inventory of radionuclides• limitation of the external dose rate• criticality safety

Merging of results / final evaluation

Approval certificate

Assessment of• mechanical/thermal design• leak tightness• quality assurance

Assessment report

Renewal after 3 / 5 / 10 / 10+ years

Design approval of transport casks

No additional constraints for transport of higher burnup/MOX spent fuel

However, the compliance with safety functions has to be proven in the same way, as for any other transport package!

Recent applications:

• package design approvals for burnups up to 80 GWd/tHM for BWR up to 75 GWd/tHM for PWR

Special issues arising for high burnup fuel assemblies

• Validation of burnup calculation codes

• 80 GWd/tHM for Uranium, PWR + BWR

• 80 GWd/tHM for MOX, PWR

• Structural analysis of fuel rods, NCT

• 3% failure of fuel rods for <50 GWd/tHM

• 100 % failure of fuel rods for ≥ 50 GWd/tHM

• affects confinement and containment

design

approvals

according to

SSR-6

Research / open questions

The BfE has identified ageing effects as a major field of interest [5,6]

• lack of data for assessing extended interim storage and subsequent transport

As a regulatory agency, it is crucial to actively follow the state of science and technology, f.e.

• tightness of double-lid system, durability of metal seals (BAM, [3])

• durability of structural components of fuel assemblies / cladding tubes

• Special inventories, like vitrified waste, defects on fuel rods, FA from research reactors, …

More general:

• interplay of temperature (decrease of decay heat), high burnup, cladding, type of FA, …

• build up of fission gases, chemical processes

• validity of computer codes (in relation to higher burnup)

[5] Bundesamt fürkerntechnische Entsorgungssicherheit, Forschungsagenda (Konsultationsfassung), Stand: Oktober 2018

[6] Bundesamt fürkerntechnische Entsorgungssicherheit, Forschungsstrategie (Konsultationsfassung), Stand: Oktober 2018

[7] S. Nagelschmidt et al. „Long-term investigations of metal seals for storage casks of radioctive materials“, PVP ASME 2016, Vancouver, Canada

Transport casks currently in use – CASTOR® V/19

Source: https://www.gns.de/

GNS Gesellschaft für Nuklear-Service mbH, Germany

Up to 19 PWR fuel assemblies

▪ Total thermal output: 39 kW

▪ Total activity: 1900 PBq

▪ Total height: 594 cm

▪ Outer diameter: 244 cm

▪ Empty weight ≈ 108 t

Validity of design approval: 16.11.2017 - 16.11.2022

Standard FA: MOX or U – up to 65 GWd/tHM

Maximum local burnup in quivers up to 120 GWd/tHM

Transport casks currently in use – CASTOR® V/52

Source: https://www.gns.de/

GNS Gesellschaft für Nuklear-Service mbH, Germany

Up to 52 BWR fuel assemblies

▪ Total thermal output: 40 kW

▪ Total activity: 1730 PBq

▪ Total height: 553 cm

▪ Outer diameter: 244 cm

▪ Empty weight ≈ 105 t

Standard FA: MOX – up to 65 GWd/tHM

U – up to 67 GWd/tHM

Maximum number of 8 non-standard fuel assemblies up to 80 GWd/tHM

Maximum local burnup in quivers up to 120 GWd/tHM

Validity of design approval: 01.12.2017 - 01.12.2022

Transport casks currently in use – TN® 24 E

Maximum burnup of 65 GWd/tHM

Up to 17 MOX-FA

Source: design approval certificate / BfE / TN International

Up to 21 PWR fuel assemblies

▪ Total thermal output: 39 kW

▪ Total activity: 1.28 PBq

▪ Total height: 587 cm

▪ Outer diameter: 252 cm

▪ Weight (loaded) ≈ 138 t

Validity of design approval: 24.07.2018 - 24.07.2023

TN International

Transport casks currently in use – NCS 45

Source: https://daher-nuclear-technologies.com/ncs-45/

Maximum burnup of 120 GWd/tHM (with limitations on masses)

MOX or uranium with max. 7%-U235

BWR and PWR fuel pins / complete FA▪ Total thermal output: 3 kW ▪ Total activity: 2000 TBq

▪ Total height: 531 cm ▪ Outer diameter: 73 cm▪ Weight (loaded) ≈ 22,7 t

Validity of design approval: 24.07.2018 - 24.07.2023

Conclusion

• Ongoing search for a deep geological repository • requires extended (40+ years) interim storage of SNF and subsequent transport

• Transport and interim storage high burnup SNF• pursuing a graded approach in licensing

A better understanding of ageing effects was identified as important for the BfE as the CA for granting approval for extended interim storage and transport of SNF.

• follow and develop the state of science and technology

• promote innovative approaches

• critically review current approaches for identifying lacks of knowledge

• scientific exchange while maintaining and developing knowledge

Thank you for your attention!

Literature / Sources

[1] Bundesamt für kerntechnische Entsorgungssicherheit: “Statusbericht zur Kernenergienutzung in der Bundesrepublik Deutschland 2018”, urn:nbn:0221-2019081919007, Salzgitter. 08/19

[2]Empfehlung der Entsorgungskommission, revidierte Fassung vom 10.06.2013: „Leitlinien für die trockene Zwischenlagerung bestrahlter Brennelemente und Wärme entwickelnder radioaktiver Abfälle in Behältern“

[3] Empfehlung der Entsorgungskommission vom 13.03.2014: „ESK-Leitlinien zur Durchführung von periodischen Sicherheitsüberprüfungen und zum technischen Alterungsmanagement für Zwischenlager für bestrahlte Brennelemente und Wärme entwickelnde radioaktive Abfälle“

[4] In “Zwischenlagerung hoch radioaktiver Abfälle” , Springer 2017: ”Wissenschaftlich-technische und rechtliche Aspekte fürGenehmigungsverfahren nach §6 AtG zur Aufbewahrung bestrahlter Kernbrennstoffe über 40 Jahre hinaus”, T. Zeiger, C. Gastl, F. Töpfer, S. Witte, K. Reichel, C. Bunzmann

[5] Bundesamt für kerntechnische Entsorgungssicherheit, Forschungsagenda (Konsultationsfassung), Stand: Oktober 2018

[6] Bundesamt für kerntechnische Entsorgungssicherheit, Forschungsstrategie (Konsultationsfassung), Stand: Oktober 2018

[7] S. Nagelschmidt et al. „Long-term investigations of metal seals for storage casks of radioctive materials“, PVP ASME 2016, Vancouver, Canada

https://www.gns.de/ https://www.orano.group/en https://www.daher.com/

https://www.bfe.bund.de/ https://www.bam.de/