Fuel and shield component development: SNAP-50
Parametric studies of 2 to 40 MW(t) reactors were based upon UC and UN (0.95 and 0.80 dense), UO/sub 2/ (0.95 dense), and cermet fuels with tungsten and molybdenum binders and UN, UC, and UO/sub 2/ dispersions. The nominal design lifetime was 10,000 hours. All reactors studied were controlled by radiatively- cooled rotating reflector segments and used pin type fuel elements. Fuel elements consisted of right cylindrical pellets in thin wall (0.015 mil) niobium alloy tubes. A fission gas plenum was provided at the end of the fuel element to accomnodate the design release. Heliarc welded end caps provided leak tight seals and an internal helium atmosphere. At the 2 MW(t) power level, typical of that required for the 300 kW(e) SNAP-50 space powerplant, the 0.95 dense UN, niobium alloy clad fuel system was found to provide the lightest weight reactor and was selected for the PWAR-20 reactor. The reactor size and weight were limited by nuclear criticality considerations and fuel performance. At 10 MW(t) which is typical of reactor power required for a 1 MW(e) powerplant, the studies indicated that a criticality limited 0.95 dense UN fuel reactor would require a maximum fuel burnup of 2.8 a/o U for 10,000 hours of operation. Based on the study conditions, this reactor was approximately 30% heavier than a UN-W reactor, which was criticality limited at 4.9 a/o U burnup. Thus fuel system development to extend the present 1.5 a/o U burnup limit of the high density UN fuel and to evaluate the irradiation stability of the cermet fuel was required to provide a basis for designing future minimum weight to 10 MW(t) reactors. The development of SNAP-50 pressure vessel, reflector, control system, and shields is reviewed. 54 references. (auth)
- Research Organization:
- Pratt and Whitney Aircraft, Middletown, Conn. (USA). Connecticut Advanced Nuclear Engineering Lab.
- DOE Contract Number:
- AT(30-1)-2789
- NSA Number:
- NSA-29-023658
- OSTI ID:
- 4310979
- Report Number(s):
- PWAC-484
- Resource Relation:
- Other Information: Declassified 12 Sep 1973. Orig. Receipt Date: 30-JUN-74
- Country of Publication:
- United States
- Language:
- English
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