Massive subcritical compact arrays of plutonium metal

Technical Report · Wed Apr 01 04:00:00 EST 1998

DOI:https://doi.org/10.2172/677063· OSTI ID:677063

Rothe, R E

Two experimental critical-approach programs are reported. Both were performed at the Rocky Flats Plant near Denver, Colorado; and both date back to the late 1960s. Both involve very large arrays of massive plutonium ingots. These ingots had been cast in the foundry at the Rocky Flats Plant as part of their routine production operations; they were not specially prepared for either study. Consequently, considerable variation in ingot mass is encountered. This mass varied between approximately 7 kg and a little more than 10 kg. One program, performed in the spring of 1969, involved stacked arrays of ingots contained within cylindrical, disk-shaped, thin, steel cans. This program studied four arrays defined by the pattern of steel cans in a single layer. The four were: 1 x N, 3 x N, 2 x 2 x N, and 3 x 3 x N. The second was a tightly-packed, triangular-pitched patterns; the last two were square-pitched patterns. The other program, performed about a year earlier, involved similar ingots also contained in similar steel cans, but these canned plutonium ingots were placed in commercial steel drums. This study pertained to one-, two-, and three-layered horizontal arrays of drums. All cases proved to be well subcritical. Most would have remained subcritical had the parameters of the array under study been continued infinitely beyond the reciprocal multiplication safety limit. In one case for the drum arrays, an uncertain extrapolation of the data of the earlier program suggests that criticality might have eventually been attained had several thousand additional kilograms of plutonium been available for use.

• Research Organization: Lockheed Martin Idaho Technologies Co., Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC07-94ID13223
• OSTI ID: 677063
• Report Number(s): INEEL/EXT--98-00293; ON: DE98058458
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CASTINGS
CRITICALITY
EXPERIMENTAL DATA
MULTIPLICATION FACTORS
Nuclear Criticality Safety Program (NCSP)
PLUTONIUM
ROCKY FLATS PLANT
SAFETY ANALYSIS
STORAGE