atw 2018-05v6

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atw Vol. 63 (2018) | Issue 5 ı May

with negligible heat generation has

been considered from the generation

of waste through the conditioning and

packaging of the various waste

streams according to the Konrad

disposal conditions to the final

disposal documentation.

The developed calculation tool

considers the change of the waste

properties by the respective conditioning

procedures and determines

the optimal variant for a container

loading according to the selected

parameter. The restrictions regarding

radiology, volume, mass, conditioning

processes and available technical

facilities at the site are taken into

account and inadmissible loading

variants are excluded by the calculation

tool.

The calculation tool is based on a

modular structure. By using the

different input data, Bethoven creates

an overview about the needed information

to the determined optimal

packaging variant and a waste data

sheet according to the Konrad disposal

conditions.

The calculation tool has been

validated on the basis of data from

already conditioned repository containers.

Furthermore extrapolations

were made for raw waste on the basis

of data from NaPro. The validation

demonstrates the range of possibilities

for optimisation by using a calculation

tool for packaging planning.

With different level of detail, the calculation

tool can be used to optimise

the packaging process.

Perspective, the calculation tool is

to be supplemented with established

planning and calculation tools for

dismantling, handling, logistics and

material flows. This coupling establishes

the calculation tool for using at

holistic disposal planning for the

decommissioning activities of nuclear

facilities and guarantees the optimal

utilization of the resources like time,

exposure time for the executive staff,

costs and available volume of the

Konrad repository.

References

[1] Anthofer, A.; Schubert, J.: Repository

Documentation Rethought. ATW,

Vol. 62 (2017), Issue 11, November.

Page 649-653.

[2] Arbeitskreis Abfallmanagement des

VGB PowerTech e.V.: Entsorgung von

Kernkraftwerken: Eine technisch gelöste

Aufgabe. Essen, 2011.

[3] Bundesamt für Strahlenschutz:

Anforderungen an endzulagernde

radioaktive Abfälle (Endlagerungsbedingungen).

Endlager Konrad,

Fachbereich Sicherheit nuklearer

Entsorgung. Stand: Dezember 2014.

Salzgitter, 2014.

[4] Baumann, R.: Nachweis der Endlagerfähigkeit

von radioaktiven Abfallgebinden,

die nach den (vorläufigen)

Konrad-Endlagerungsbedingungen

(Dez. 1995) hergestellt wurden.

Siemens AG, Symposium Endlagerung

radioaktiver Abfälle. Oktober 2014.

[5] Karbstein, L.; Anthofer, A.; Borchardt,

R.; Reithmeier, H.: Konradgerechte

Konditionierung der ANTARES-Shutterbaugruppe

aus dem FRM II; Kontec 17;

Dresden, 2017.

[6] Bundesministerium für Umwelt,

Naturschutz, Bau und Reaktorsicherheit:

Verzeichnis radioaktiver Abfälle,

Bestand zum 31. Dezember 2013 und

Prognose.

Authors

Dipl.-Ing. Johannes Schubert

Dr.-Ing. Anton Philipp Anthofer

Dipl.-Ing. Max Schreier

VPC GmbH

Fritz-Reuter-Straße 32c

01097 Dresden, Germany

DECOMMISSIONING AND WASTE MANAGEMENT 319

Scope for Thermal Dimensioning

of Disposal Facilities for High-level

Radioactive Waste and Spent Fuel

Joachim Heierli, Helmut Hirsch, Bruno Baltes

Introduction The objective of final disposal of high-level radioactive waste in deep geological formations is to

isolate the radionuclides from the accessible biosphere for a sufficient period of time [IAEA 2011; IAEA 2012]. To achieve

this, both the functionality and the integrity of the disposal system must be assured under ambient conditions that

depend both on the geological environment and on engineering choices taken in the planning of the facility.

In particular, the amplitude of the transient temperature increase caused by the release of nuclear decay heat in the

disposal area is scalable through design strategies and thermal dimensioning.

The trade-offs between hotter and

cooler repository designs are multiple

and complex [Whipple et al. 1999]. In

many ways, the ambient temperature

influences the physical processes

taking place in and around the repository.

For example, hotter designs

delay liquid water contact with

corrodible barrier materials and, with

it, liquid-phase oxidation-reduction

reactions. In some environments, they

cause faster convergence of circumambient

rock [Mönig et al. 2013] or

tend to eliminate the excavation

damage zone as a possible by-pass

for radionuclides to escape [Beswick et

al. 2014]. On the other hand, cooler

designs decrease the rates of thermally

activated diffusion-reaction processes,

induce smaller changes to the natural

system, alleviate pore or crack water

pressures in the circumambient rock

[Gens et al., 2017; Wieczorek 2017]

and are likely easier to analyse [Whipple

et al. 1999]. In geologic repositories

relying on the barrier properties

of smectite-rich materials such as

argillaceous rock or bentonite,

increased peak temperatures in the

hydro-chemical environment raise the

difficulties of substantiating the safety

case with a satisfactory level confidence

[Heierli 2016; Huang et al.

1993]. Pertaining to operational

aspects, high temperatures produce

adverse working conditions for human

or machine operated underground

activities. For example, the retrievability

of waste, either limited or

Decommissioning and Waste Management

Scope for Thermal Dimensioning of Disposal Facilities for High-level Radioactive Waste and Spent Fuel ı Joachim Heierli, Helmut Hirsch, Bruno Baltes

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