Coupled Thermo-Hydraulic Behavior Around Access Shaft Sealed with Backfill Material

1990 ◽  
Vol 212 ◽  
Author(s):  
J. Okamoto ◽  
K. Ishihara ◽  
Y. Sawauchi ◽  
K. Hara ◽  
N. Sasaki

ABSTRACTGroundwater flow from the repository to the surface through the sealed access shaft may be induced by the heat generated from high-level radioactive waste(HLW). It is important to estimate the effect of this heat generation on groundwater flow.This paper presents an evaluation of groundwater flow in the vicinity of an access shaft filled with a backfill material. The evaluation uses a coupled thermo-hydraulic model. According to the current design, the backfill material within the shaft will be tamped 5 to 15 times every 20 cm depth using a 60 kg vibrating compactor. The properties of the backfill material were determined from experimental results for this construction method.A transient coupled thermo-hydraulic analysis was carried out using an axisymmetric FEM model. Two kinds of repository models were considered, one was a single layered repository located at 1000 m depth, and the other was a two layered repository located at 800 m and 1000 m depths. The access shaft of each model was located at the center of the repository.The results show that the vertical hydraulic gradient of groundwater flow along the sealed shaft will be approximately 0.001 at a time 1000 years after closure of the repository.

2021 ◽  
pp. 60-66
Author(s):  
D. Anopko ◽  
O. Honchar ◽  
M. Kochevykh ◽  
L. Kushnierova

The radiation resistance of concrete under the influence of large doses of gamma radiation was investigated. To study the behavior of concrete under the influence of gamma radiation, two series of samples were taken: оne was the reference sample, and the other was exposed to gamma radiation. The temperature of the irradiated samples during testing did not exceed 40 °C, the reference temperature was also accepted to be 40 °C. The dose of gamma radiation was 109 rad. Its value corresponds to the dose that concrete can receive when it comes into contact with high-level radioactive waste from the Shelter over 300 years. Characteristics of an industrial gamma radiation equipment are: radiation energy is 1.25 MeV and dose rate is 2 Mrad/h. The use of such equipment allows reaching a dose of 109 rad in less than a month, and 108 rad - in 4-5 days. Concretes that were 28 days old and stored under normal conditions were exposed to gamma radiation.


1981 ◽  
Vol 11 ◽  
Author(s):  
Ivars Neretnieks

The release rate of radionuclides from a degraded canister containing radioactive waste is controlled by diffusion through the backfill and by diffusion into the water flowing past the canister. In low porosity low permeability bedrock like the Swedish granites the amount of water which can be contaminated may be very small. Two sample cases are calculated. One uses the conditions for a repository for vitrified high level waste, the other applies to a repository for spent fuel. The small amount of water which can carry the waste in combination with the low solubilities for the major longlived actinides limit the release rate from the repositories to very small values.


1970 ◽  
Vol 1 (2) ◽  
pp. 34-36
Author(s):  
Mehedi Imam

In Bangladesh, demand for judicial independence in practice has been a much debated issue and the demand is fulfilled but expectation of people is not only limited to have an independent judiciary but to have an impartial system and cadre of people, which will administer justice rationally being free from fear or force. The independence of judiciary and the impartial judicial practice are related concepts, one cannot sustain without the other and here existence as well as the need of practicing impartiality is well recognized. But the art of practicing impartiality does not develop overnight as it’s related to development of one’s attitude. It takes a considerable time resulting from understanding, appreciating and acknowledging the moral values, ethics and professional responsibility. The judiciary includes Judges, Advocates mostly who are expected to demonstrate a high level of moral values and impartiality towards people seeking justice and ‘rule of law’. This is true that bench officers and clerks are also part of the process to ensure rule of law with same level of participation by the law enforcing agencies such as police. However the paper includes only those who either join judiciary as Judge/Magistrate or Advocate to explore level and extent of ethical knowledge they receive being key role players of the system. DOI: http://dx.doi.org/10.3329/bioethics.v1i2.9628 Bangladesh Journal of Bioethics 2010; 1(2): 34-36


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