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Material Science_ Vol 2 of 2 - US DOE (1993) WW part 11

Tham khảo tài liệu 'material science_ vol 2 of 2 - us doe (1993) ww part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Plant Materials DOE-HDBK-1017 2-93 SHIELDING MA TERIALS Since alpha and beta particles can be easily shielded against they do not present a major problem in the nuclear reactor plant. Summary The important information in this chapter is summarized below. Shielding Materials Summary Neutron Radiation Low mass number and high cross section preferably hydrogenous material for low energies. Water ranks high due to advantage of low cost ready means for removing heat. Good inelastic scattering properties high energies . Iron is used due to the large change in neutron energy after collision but it has little effect on lower energy neutrons. Gamma Radiation High atomic mass number and high density are required to attenuate Y radiation. Lead has advantage of ease of fabrication. The disadvantage of lead is its low melting point. Iron is used for higher and lower energies. Iron is selected based on structural temperature and economic considerations. Water can be used but requires large amounts because water is a poor absorber of gamma radiation. Concrete is a good gamma attenuator as a general shield material. Concrete is strong inexpensive and adaptable to different types of construction. Alpha and Beta Radiation No particular shielding material is required to guard against alphas and betas. Rev. 0 Page 21 MS-05 NUCLEAR REACTOR CORE PROBLEMS DOE-HDBK-1017 2-93 Plant Materials NUCLEAR REACTOR CORE PROBLEMS Material problems in a nuclear reactor plant can be grouped into at least two categories one concerning the nuclear reactor core and one that will apply to all plant materials. This chapter discusses specific material problems associated with the reactor that include pellet-cladding interaction fuel densification fuelcladding embrittlement and effects on fuel due to inclusion and core burnup. EO 1.12 STATE nuclear reactor core problems and causes associated with the following a. Pellet-cladding interaction b. Fuel densification c. Fuel cladding embrittlement d. Fuel burnup