Evaluation of Radiation Effects on Residents Living Around the NSRR Under External Hazards

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Yuiko Motome ◽  
Yoshiya Akiyama ◽  
Hiroyuki Murao
Keyword(s):  
Radiation Effects ◽  
Research Reactor ◽  
Reactor Core ◽  
Fission Products ◽  
Internal Exposure ◽  
Spent Fuel ◽  
Loss Of Function ◽  
Safety Research ◽  
Spent Fuel Storage ◽  
Fuel Storage

Abstract The nuclear safety research reactor (NSRR) is a research reactor of training research isotopes general atomics—annular core pulse reactor (TRIGA-ACPR) type, located in the Nuclear Science Research Institute (NSRI). The NSRR facility has been utilized for fuel irradiation experiments to study the behaviors of nuclear fuels under reactivity-initiated accident (RIA) conditions. Under the new regulation standards, which was established after the Fukushima Daiichi accident, research reactors are regulated based on the risk of the facilities. The graded approach is introduced in the regulation. To apply the graded approach, the radiation effects on residents living around the NSRR under the external hazards were evaluated, and the level of the risk of the NSRR facility was investigated. This paper summarizes the result of the evaluation in the case where the safety functions are lost due to a tornado, an earthquake followed by a tsunami. There is fuel in the reactor core, fresh fuel storage, and spent fuel storage. As the effects from reactor core, we evaluate the external exposure to radiation and exposure from the release of fission products assuming that loss of function to shut down the reactor, break of cladding tubes, loss of reactor pool water, and collapse of the reactor building. As the effects from fresh fuel storage, we evaluate the internal exposure assuming that the fresh fuel particles released into the air because of breaking into pieces. In addition, we evaluate the critical safety assuming that the critical safety shapes of the fresh fuel storage are lost. As the effects from spent fuel storage, we evaluate the critical safety assuming that the critical safety shapes of the spent fuel storage are lost. All in all, the risk is confirmed to be relatively low, since the effective dose on the residents is found to be below 5 mSv per event due to the loss of the safety functions caused by the tornado, earthquake, and the accompanying tsunami.

Recommendations for Conducting Probabilistic Risk Assessment of Spent Fuel Storage Facilities

2017 ◽  
Author(s):  
Sai Zhang ◽  
Jun Zhao ◽  
Jiejuan Tong ◽  
Zhixin Xu
Keyword(s):  
Nuclear Power ◽  
Reactor Core ◽  
Spent Fuel ◽  
Complementary Method ◽  
Fuel Assemblies ◽  
Spent Fuel Storage ◽  
Fuel Storage ◽  
Storage Units ◽  
Storage Facilities ◽  
Probabilistic Risk

Currently, the probabilistic risk assessments (PRA) for the nuclear power plant (NPP) sites are primarily focused on the reactor counterpart. However, evoked by the 2011 Fukushima Daiichi accident, it has been widely recognized that a complete site risk profile should not be confined to the reactor units, but should cover all the radiological sources in a site, e.g. spent fuel storage facilities. During the operation of the reactor units, the used fuel assemblies will be unloaded from the reactor core to the storage facilities in a continuous or periodical manner. Accident scenarios involving such facilities can occur with non-negligible frequencies and significant consequences, posing threat to public safety. Hence, the risk contributions from such scenarios should be carefully estimated and integrated into the safety goal evaluations. The spent fuel storage facilities can be categorized as two types: pool storage units and dry cask storage facilities. In the former type, spent fuel assemblies are stored in large pools inside or outside the reactor building, with the residual heat removed by natural or forced water circulation. The latter type, where air or inert gas circulation plays an important role, appear mostly as a complementary method, along with the pool storage units, to expand the plant’s storage capacity. For instance, at the Daiichi plant, there are several fuel pool units holding some fresh fuel and some used fuel, the latter awaiting for its transfer to the dry cask storage facilities on site. Note that, as well as in a joint manner, both storage facilities can be designed to serve the NPPs independently. As a fully developed method to identify potential risk in a logical and quantitative way, the framework of PRA can be generally applied to the spent fuel storage facilities with some special considerations. This paper is aimed at giving recommendations for the spent fuel storage facility PRAs, including (1) clarifying the analysis scope of risk from spent fuel storage facilities; (2) illustrating four key issues that determines such risk; (3) presenting three essential considerations when conducting PRAs to evaluate such risk. Also, this paper integrates the insights obtained from two representative case studies involving two NPP sites with different types of both fuel elements and storage facilities.

scholarly journals Study of corrosion of aluminium alloys of nuclear purity in ordinary water, пart one

2004 ◽  
Vol 19 (2) ◽  
pp. 77-93 ◽  
Author(s):  
Milan Pesic ◽  
Tatjana Maksin ◽  
Gabrijela Jordanov ◽  
Rajko Dobrijevic ◽  
Zoja Idjakovic
Keyword(s):  
Aluminum Alloys ◽  
Research Reactor ◽  
Initial Study ◽  
Spent Fuel ◽  
Energy Agency ◽  
Ordinary Water ◽  
Storage Pool ◽  
Spent Fuel Storage ◽  
Fuel Storage ◽  
Frame Work

Effects of corrosion of aluminum alloys of nuclear purity in ordinary water of the spent fuel storage pool of the RA research reactor at VINCA Institute of Nuclear Sciences has been examined in the frame work of the International Atomic Energy Agency Coordinated Research Project "Corrosion of Research Reactor Aluminum-Clad Spent Fuel in Water" since 2002. The study presented in this paper comprises activities on determination and monitoring of chemical parameters and radio activity of water and sludge in the RA spent fuel storage pool and results of the initial study of corrosion effects obtained by visual examinations of surfaces of various coupons made of aluminum alloys of nuclear purity of the test racks exposed to the pool water for a period from six months to six years.

Scientific Basis for Storage Criteria for Interim Dry Storage of Aluminum-clad Fuels

1995 ◽  
Vol 412 ◽  
Author(s):  
R. L. Sindelar ◽  
H. B. Peacock ◽  
P. S. Lam ◽  
N. C. Iyer ◽  
M. R. Louthan ◽  
...  
Keyword(s):  
Research Reactor ◽  
Storage Temperature ◽  
Fission Products ◽  
The United States ◽  
Scientific Basis ◽  
Department Of Energy ◽  
United States Department ◽  
Spent Fuel ◽  
Dry Storage ◽  
Fuel Storage

AbstractAn engineered system for dry storage of aluminum-clad foreign and domestic research reactor spent fuel owned by the United States Department of Energy is being considered to store the fuel up to a nominal period of 40 years prior to ultimate disposition. Scientifically-based criteria for environmental limits to drying and storing the fuels for this system are being developed to avoid excessive degradation in sealed and non-sealed (open to air) dry storage systems. These limits are based on consideration of degradation modes that can cause loss of net section of the cladding, embrittlement of the cladding, distortion of the fuel, or release of fuel and fission products from the fuel/clad system. Potential degradation mechanisms include corrosion mechanisms from exposure to air and/or sources of humidity, hydrogen blistering of the aluminum cladding, distortion of the fuel due to creep, and interdiffusion of the fuel and fission products with the cladding.The aluminum-clad research reactor fuels are predominantly highly-enriched aluminumuranium alloy fuel which is clad with aluminum alloys similar to 1100, 5052, and 6061 aluminum. In the absence of corrodant species, degradation due to creep and diffusion mechanisms limit the maximum fuel storage temperature to 200°C. The results of laboratoryscale corrosion tests indicate that this fuel could be stored under air up to 200°C at low relative humidity levels (< 20%) to limit corrosion of the cladding and fuel (exposed to the storage environment through assumed pre-existing pits in the cladding). Excessive degradation of fuels with uranium metal up to 200°C can be avoided if the fuel is sufficiently dried and contained in a sealed system; open storage can be achieved if the temperature is controlled to avoid excessive corrosion even in dry air.

On the Corrosion of Spent Fuel Aluminium Cladding During Wet Storage

2008 ◽  
Vol 59 (2) ◽  
pp. 178-180
Author(s):  
Cristina Ciuculescu ◽  
Tanase Dobre
Keyword(s):  
Chemical Analysis ◽  
Water Samples ◽  
Research Reactor ◽  
Spent Fuel ◽  
Fuel Cladding ◽  
Storage Pool ◽  
Wet Storage ◽  
Spent Fuel Storage ◽  
Fuel Storage

The paper presents the results obtained from the curves curent-potential when Al-Mg3 samples polarization occurs in solutions that simulate the water from the storage pool. The samples used in research are characteristic for the fuel spent C-36 and EK-10 and also for the storage pool from the Magurele- Romania research reactor deactivation. The study is unique due to the material samples used and due to the fact that the results of electrochemical experiments are correlated to the results from the chemical analysis of water samples from spent fuel storage basins. The paper is in the class of those which serve to the estimation of the dynamics of the degradation of spent fuel cladding during wet storage.

Influence of Gap Size on Added Mass for Spent Fuel Storage Rack

2018 ◽  
Author(s):  
Daogang Lu ◽  
Yu Liu ◽  
Shu Zheng
Keyword(s):  
Vibration Frequency ◽  
Input Parameter ◽  
Added Mass ◽  
Water Tank ◽  
Spent Fuel ◽  
Free Standing ◽  
Fluid Force ◽  
Spent Fuel Storage ◽  
Fuel Storage ◽  
Spent Fuel Pool

Free standing spent fuel storage racks are submerged in water contained with spent fuel pool. During a postulated earthquake, the water surrounding the racks is accelerated and the so-called fluid-structure interaction (FSI) is significantly induced between water, racks and the pool walls[1]. The added mass is an important input parameter for the dynamic structural analysis of the spent fuel storage rack under earthquake[2]. The spent fuel storage rack is different even for the same vendors. Some rack are designed as the honeycomb construction, others are designed as the end-tube-connection construction. Therefore, the added mass for those racks have to be measured for the new rack’s design. More importantly, the added mass is influenced by the layout of the rack in the spent fuel pool. In this paper, an experiment is carried out to measure the added mass by free vibration test. The measured fluid force of the rack is analyzed by Fourier analysis to derive its vibration frequency. The added mass is then evaluated by the vibration frequency in the air and water. Moreover, a two dimensional CFD model of the spent fuel rack immersed in the water tank is built. The fluid force is obtained by a transient analysis with the help of dynamics mesh method.

scholarly journals Antineutrino background from spent-fuel storage in sensitive searches for θ 13 at reactors

2006 ◽  
Vol 69 (2) ◽  
pp. 185-188 ◽  
Author(s):  
V. I. Kopeikin ◽  
L. A. Mikaelyan ◽  
V. V. Sinev
Keyword(s):  
Spent Fuel ◽  
Spent Fuel Storage ◽  
Fuel Storage
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