Nuclear Techniques ›› 2020, Vol. 43 ›› Issue (8): 80007-080007.

• SPECIAL SECTION ON THE 11TH NATIONAL CONFERENCE ON NEW AND RESEARCH REACTORS (PART III) •

### Neutronics analysis of commercial pressurized water reactor loaded with FCM fuel

Xue QIN,Mancang LI,Hongkuan LIAO,Yingrui QIN Dong YU,Zhumin JIANG,Shuai WANG,Yun CAI,Rui GUO

1. Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610041, China
• Received:2020-05-25 Revised:2020-06-25 Online:2020-08-15 Published:2020-08-12
• About author:QIN Xue, female, born in 1989, graduated from from Chongqing University with a master's degree in 2012, focusing on reactor physics

Abstract: Background

During the Fukushima accident, the shortcomings of the existing UO2-zirconium alloy fuel form in resisting severe accidents were exposed. Fully ceramic microencapsulated fuel (FCM) disperses tri-structural iso-tropic (TRISO) fuel particles in a SiC matrix and has the ability to contain fission products, hence can effectively improve the ability of nuclear fuel to maintain structural integrity under severe accidents. FCM fuel can reduce the risk of large quantities of radioactive materials leakage in nuclear power plants, it is one of the main research objects of accident tolerant fuel (ATF). Compared with the traditional UO2 ceramic fuel pellets, the U loading of FCM fuel has better moderation ability and less U loading. When the FCM fuel is used in a commercial pressurized water reactor (PWR), it may cause the positive moderator temperature coefficient (MTC) and loss of inherently safety of the core.

Purpose

This study aims to analyse the neutronics characteristics of commercial PWR using FCM fuel from the perspective of inherent safety and economy.

Methods

The UO2-Zr alloy fuel assemblies in the form of standard AFA3G 17×17 grid were taken as reference objects. The NESTOR software independently developed by China national nuclear corporation (CNNC) was employed to analyse the neutron characteristics of FCM fuel (UN core) assembly in forms of 17×17 grid and 13×13 grid. The overall physical performances of the reactor core composed of FCM fuel (UN core) in the form of a 13×13 grid were evaluated.

Results

Computational results show that FCM fuel (UN core) assembly in the form of 13×13 grid containing gadolinium poisons meets the requirements of under moderation, and the FCM fuel (UN core) assembly in the form of 13×13 grid can be adapted by large commercial PWR with negative MTC at the initial stage while the fuel consumption depth and cycle length of the first cycle core are basically equivalent to those of the reference core.

Conclusions

FCM fuel assemblies used in commercial PWR can initially meet the inherent security and economic requirements. Further research work will be carried out to optimize the analysis of core power flattening.

Key words: FCM fuel, PWR, Neutronics analysis

CLC Number:

• TL32