Details
| Original language | English |
|---|---|
| Pages (from-to) | 361-372 |
| Number of pages | 12 |
| Journal | Radiation Protection Dosimetry |
| Volume | 177 |
| Issue number | 4 |
| Publication status | Published - 2 May 2017 |
Abstract
In several countries, the high-level radioactive waste that will be disposed of in deep geological formations has to be retrievable for a certain time. Since 2010, retrievability is required for the operation phase of a repository also in Germany. Depending on the effort and the feasibility of remote handling, a certain exposure of the involved employees to ionising radiation is caused. The estimation of the exposure requires the knowledge of the inventory of radionuclides and the radiation field around the storage containers. This paper focuses on German concepts for final storage casks for the drift emplacement in rock salt for both spent fuel rods and high-active waste (HAW) coquilles. Calculations of dose rates at the surfaces of the casks are presented. The calculations show that the gamma radiation of fission and activation products can be efficiently shielded by materials like cast iron or low-alloyed steel. Ductile cast iron, however, has a positive influence on the neutron moderation because of the high carbon content. The shielding of the neutron radiation strongly depends on the quantity and position of the polyethylene (PE) rods which are used as neutron moderator. PE has unfavourable features at elevated temperatures that can be reached in a repository for high-level waste. The simulations show that TiH2 is a promising alternative material for the shielding of neutron radiation. The current assumption that a final storage cask for HAW coquilles has the same outer dimensions as the cask for spent fuel rods will lead to unacceptable dose rates at the side wall. An increase of the diameter is necessary to provide sufficient shielding. Graphite insets in the cask interior lead to a considerably lowered dose rate.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Radiation
- Health Professions(all)
- Radiological and Ultrasound Technology
- Medicine(all)
- Radiology Nuclear Medicine and imaging
- Medicine(all)
- Public Health, Environmental and Occupational Health
Sustainable Development Goals
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In: Radiation Protection Dosimetry, Vol. 177, No. 4, 02.05.2017, p. 361-372.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Calculation of dose rates at the surface of storage containers for high-level radioactive waste
AU - Pönitz, Erik
AU - Walther, Clemens
N1 - Funding information: This work was financially supported by the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF) under the research grant 15S9082A.
PY - 2017/5/2
Y1 - 2017/5/2
N2 - In several countries, the high-level radioactive waste that will be disposed of in deep geological formations has to be retrievable for a certain time. Since 2010, retrievability is required for the operation phase of a repository also in Germany. Depending on the effort and the feasibility of remote handling, a certain exposure of the involved employees to ionising radiation is caused. The estimation of the exposure requires the knowledge of the inventory of radionuclides and the radiation field around the storage containers. This paper focuses on German concepts for final storage casks for the drift emplacement in rock salt for both spent fuel rods and high-active waste (HAW) coquilles. Calculations of dose rates at the surfaces of the casks are presented. The calculations show that the gamma radiation of fission and activation products can be efficiently shielded by materials like cast iron or low-alloyed steel. Ductile cast iron, however, has a positive influence on the neutron moderation because of the high carbon content. The shielding of the neutron radiation strongly depends on the quantity and position of the polyethylene (PE) rods which are used as neutron moderator. PE has unfavourable features at elevated temperatures that can be reached in a repository for high-level waste. The simulations show that TiH2 is a promising alternative material for the shielding of neutron radiation. The current assumption that a final storage cask for HAW coquilles has the same outer dimensions as the cask for spent fuel rods will lead to unacceptable dose rates at the side wall. An increase of the diameter is necessary to provide sufficient shielding. Graphite insets in the cask interior lead to a considerably lowered dose rate.
AB - In several countries, the high-level radioactive waste that will be disposed of in deep geological formations has to be retrievable for a certain time. Since 2010, retrievability is required for the operation phase of a repository also in Germany. Depending on the effort and the feasibility of remote handling, a certain exposure of the involved employees to ionising radiation is caused. The estimation of the exposure requires the knowledge of the inventory of radionuclides and the radiation field around the storage containers. This paper focuses on German concepts for final storage casks for the drift emplacement in rock salt for both spent fuel rods and high-active waste (HAW) coquilles. Calculations of dose rates at the surfaces of the casks are presented. The calculations show that the gamma radiation of fission and activation products can be efficiently shielded by materials like cast iron or low-alloyed steel. Ductile cast iron, however, has a positive influence on the neutron moderation because of the high carbon content. The shielding of the neutron radiation strongly depends on the quantity and position of the polyethylene (PE) rods which are used as neutron moderator. PE has unfavourable features at elevated temperatures that can be reached in a repository for high-level waste. The simulations show that TiH2 is a promising alternative material for the shielding of neutron radiation. The current assumption that a final storage cask for HAW coquilles has the same outer dimensions as the cask for spent fuel rods will lead to unacceptable dose rates at the side wall. An increase of the diameter is necessary to provide sufficient shielding. Graphite insets in the cask interior lead to a considerably lowered dose rate.
UR - http://www.scopus.com/inward/record.url?scp=85040241372&partnerID=8YFLogxK
U2 - 10.1093/rpd/ncx054
DO - 10.1093/rpd/ncx054
M3 - Article
C2 - 28472493
AN - SCOPUS:85040241372
VL - 177
SP - 361
EP - 372
JO - Radiation Protection Dosimetry
JF - Radiation Protection Dosimetry
SN - 0144-8420
IS - 4
ER -