LIQUID METAL FUEL REACTOR EXPERIMENT. Quarterly Technical Report for May 1957-September 1957

Technical Report · Tue Oct 31 00:00:00 EST 1961

OSTI ID:4119741

; 8 nty of (?) 5 in. for the reference-design critical diameter is expected to be reduced greatly as additional information on physical properties of actual reactor materials becomes available and as the results of the Liquid Metal Fuel Reactor (LMFRE) critical experiment and allied work are analyzed. For the reference design, the contribution of inelastic scattering and bismuth to the total k/sub eff/ was calculated to be about 2%. The positive xenon temperature coeificient of reactivity was recomputed, for the case of no xenon removal, and found to be in good agreement with previous calculations. The U/sup 235/ addition necessary to override fission-product poisoning was checked by raising thermal rut-off energy from 0.07 to 0.2 ev, increasing the required U/ sup 235/ additions by only 10 ppm. The relaxation length of thermal neutrons for the concrete surrounding the reactor was calculated to be approximately 8 cm. A number of inadequacies were noted in the generalized set of core transient equations reported in the last quarterly report. These equations were improved to permit a final steady-state solution, to improve treatment of the delayed neutron precursor concentration, and to introduce a radial temperature dependence in the graphite. Graphite vendors' comments on specifications and preliminary working drawings for core-end reflector assembly and side reflector indicate that (1) core OD and side-reflector ID tolerances should be relaxed slightly and (2) the design not provide access for cleaning loose scale from core fuel passages. To overcome the latter, an alternate top reflector arrangement, which includes a quadrant type graphite tank and drilled block insert, was completed. The core Bi/ C volume ratio was revised to 0.5 (on a cell basis) and top and bottom reflectors were redesigned to give a Bi/C volume ratio of 0.2 (av.) measured at the horizontal and associated internals was completed. Control-rod thermal calculations were initiated to determine the praclated fission-product poison buildup, assuming various amounts of U- Bi absorbed in graphite, indicated this effect to be unimportant in the LMFRE. The required initial U/sup 235/ concentration for the reference design was estimated to be about 8OO ppm by weight. Major preliminary design modifications affecting Systems Engineering are listed. lnvestigation of primary-system dump-time requirements indicated that a rapid dump is not required for nuclear reasons. A preliminary investigation indicated that overpressure in the reactor plant would be 7 psi following the maximum credible accident. A study to determine what data can be obtained from the ETR loop (No. 2) degasser and how this data can be used in the LMFRE degasser dedesign was started. The maximum tolerable sodium concentration in the fuel is not now apparent. Problems which might arise from sodium leaks into the fuel were considered. Uranium oxidation from the fuel could introduce varying amounts of uranium to the core, seriously damaging the reactor. The nature of uranium oxides and nitrides from ETR loop (No. 2) were studied. The number of cells for reactor and auxiliary equipment containment was reduced from 14 to 7. Any component removed from the cells can be safely stored in a 31-ft-deep storage pool adjacent ed a windowed control room, will be located in the reactor canyon above the cells. Remote maintenance equipment will be mounted on a heavy cast- iron plug stored in the canyon floor above a maintenance hot cell. There will be a steel door in one end of the canyon (for component removal) and two steel doors leading into the master control room and hot change room. The office and laboratory area will be L-shaped and the basement area beneath will house auxiliary systems not requiring heavy shielding. The building will be ventilated so the air flow is directed from the least radioactive areas to the most radioactive areas

• Research Organization: Babcock and Wilcox Co. Atomic Energy Div., Lynchburg, Va.
• DOE Contract Number: AT(30-1)-1940
• NSA Number: NSA-15-002326
• OSTI ID: 4119741
• Report Number(s): BAW-1033
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-61
• Country of Publication: United States
• Language: English

Related Subjects

REACTOR TECHNOLOGY
ABSORPTION
ACCIDENTS
BISMUTH
BUILDINGS
CONCRETES
CONTROL ELEMENTS
COOLING
CRITICALITY
DELAYED NEUTRONS
ETR
FISSION PRODUCTS
GASES
GRAPHITE MODERATOR
IN PILE LOOPS
LABORATORY EQUIPMENT
LEAKS
LIQUID METAL FUEL
MAGNESIUM
MAINTENANCE
MATHEMATICS
OXIDATION
PLANNING
POISONING
PRESSURE
PRESSURE VESSELS
RADIATION PROTECTION
REACTIVITY
REACTOR CORE
REACTORS
REFLECTORS
REMOTE HANDLING
RODS
SCATTERING
SHIELDING
SODIUM
SOLUTIONS
STORAGE
TEMPERATURE
THERMAL NEUTRONS
TRANSPORT
URANIUM
URANIUM 235
URANIUM NITRIDES
URANIUM OXIDES
XENON 135
ZIRCONIUM