Probability assessment of graphite brick in the HTR-10

Yu, Suyuan; Li, Haiyan; Wang, Chaoyang; Zhang, Zhensheng

doi:10.1016/j.nucengdes.2003.08.002

Cited by 4 publications

(2 citation statements)

References 5 publications

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“…∆σ = Ď∆ε e + ∆Dε e (4) where D is the elastic stiffness matrix. Since the Young"s modulus is dependent upon irradiation dose and temperature, D is also a function of dose and temperature.…”

Section: Constitutive Modelmentioning

confidence: 99%

“…They suggested that the one that gave a shorter lifetime should be used. Yu et al [4] used the finite element method to compute stresses in a HTR-10 (a test reactor of the pebble bed design) reflector brick and evaluated the failure probability using the Weibull model [5,6]. The dependence of physical properties such as thermal conductivity, thermal expansion coefficient, creep coefficient and elastic modulus on temperature and fast neutron dose was included in the finite element code.…”

Section: Introductionmentioning

confidence: 99%

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Failure Predictions for Graphite Reflector Bricks in the Very High Temperature Reactor with the Prismatic Core Design

Singh

Fok

Mantell

2017

Nuclear Engineering and Design

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Graphite is used in nuclear reactor cores as a neutron moderator, reflector and structural material. The dimensions and physical properties of graphite change when it is exposed to neutron irradiation. The non-uniform changes in the dimensions and physical properties lead to the build-up of stresses over the course of time in the core components. When the stresses reach the critical limit, i.e. the strength of the material, cracking occurs and ultimately the components fail. In this paper, an explicit crack modeling approach to predict the probability of failure of a VHTR prismatic reactor core reflector brick is presented. Firstly, a constitutive model for graphite is constructed and used to predict the stress distribution in the reflector brick under in-reactor conditions of high temperature and irradiation. Fracture simulations are performed as part of a Monte Carlo analysis to predict the probability of failure. Failure probability is determined based on two different criteria for defining failure time: A) crack initiation and B) crack extension to near control rod channel. A significant difference is found between the failure probabilities based on the two criteria. It is predicted that the reflector bricks will start cracking during the time range of 5-9 years, while breaching of the control rod channels will occur during the period of 11-16 years. The results show that, due to crack arrest, there is a significantly delay between crack initiation and breaching of the control rod channel.

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Section: Constitutive Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%