Fuel Assembly Reference Information for SNF Radiation Source Term Calculations

A Study on the Characteristics of the Radiation Source Terms of Spent Fuel and Various Non-Fuel Hardware for Shielding Applications

“…The materials in each fuel assembly hardware region were homogenized within the boundary of the hardware region. The physical characteristics of these fuel assemblies are documented in ORNL/SPR-2021/2093 [10]. The fuel assembly hardware regions contain activation sources.…”

“…The evaluated PWR fuel assembly types are B&W 15 ´ 15, WE 17 ´ 17 low parasitic (LOPAR), WE 17 ´ 17 OFA, and Combustion Engineering (CE) 16 ´ 16; the evaluated BWR fuel assembly types are GE 7 ´ 7, GE 8 ´ 8, ANF 9 ´ 9, and GE 10 ´ 10. The physical characteristics of these fuel assemblies are summarized in ORNL/SPR-2021/2093 [10]. A pin-by-pin representation of the fuel region for these fuel assembly types, shown in Figure 60, was used in the hypothetical transportation package model presented in Section 3.3.…”

“…In the United States, limited substitutions of Zr alloy or solid stainless-steel filler rods for fuel rods are allowed per Generic Letter 90-02 and its Supplement 1 guidance [29]. The 2013 GC-859 survey data reported that approximately 850 fuel assemblies contained replacement rods [10]. A discharged fuel assembly is not expected to contain more than 10 replacement rods [10].…”

“…The 2013 GC-859 survey data reported that approximately 850 fuel assemblies contained replacement rods [10]. A discharged fuel assembly is not expected to contain more than 10 replacement rods [10]. Depending on the actual number of replacement stainless-steel rods within a fuel assembly, 60 Co and other activation products in irradiated steel may be significant contributors to external cask dose rates.…”

“…A limited study, including calculations of 60 Co activation sources associated with cobalt impurity in BPRs, ORAs, and TPDs, is provided in this section. Data used in the calculations documented in this section were taken from ORNL/SPR-2021/2093 [10].…”