Ageing Assessment of Reactor Pressure Vessels
Date Issued
2007
Date
2007
Author(s)
Wei, Chung-Hao
DOI
zh-TW
Abstract
The reactor pressure vessel (RPV) is an extremely important component in the steam supply system of a nuclear power plant. However, after a long period of operation, it will face various aging problems that would affect the safety of the plant. Among them, radiation embrittlement is considered the major aging mechanism of the reactor pressure vessels. To evaluate the degree of radiation embrittlement and ensure the safety of the vessels, the domestic nuclear power plants adopt the standard set by the United States Nuclear Regulatory Commission (USNRC) and carry out aging assessment programs periodically. Based on the deterministic assessment procedure as required by USNRC, the present study proposes a probabilistic aging assessment model to estimate the probability of outrunning the required values set by USNRC in consideration of radiation embrittlement of reactor pressure vessels. Taking the domestic pressurized water nuclear power plant as an example, the present study shows that, under a reasonable assumption and based on the consideration of adjusted reference temperature (ART), the reactor pressure vessel might outrunning the code-required value with a probability of 3.42×10^7 at the end of its design life. If the calculation is based on the consideration of upper shelf energy (USE), the probability would become 1×10^4 . Since the required values set by USNRC are based on the rather conservative deterministic consideration, the real failure probability of the studied vessel owing to radiation embrittlement must be lower than the above mentioned values.
Subjects
壓力槽
核能反應器
脆化
輻射影響
機率
Pressure vessels
Nuclear reactors
Embrittlement
Radiation effects
Probability
Type
thesis
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