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U.S. Department of Energy
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SM-2 Flexible Critical Experiments

Journal Article · · Nuclear Science and Engineering
OSTI ID:4096320
The cold, clean, steel-reflected, final, SM-2 mock-up containing 36.4 kg U235 and 61 g B10 maintained criticality after a seven-rod bank withdrawal of 6.974 in. and had an "excess K" (delta KE) of 1520 cents. An infinite steel-water laminated reflector is worth approximately +85 cents over the infinite water-reflected core. The measured reactivity coefficient, at 2000 psi, ranged from --1.15 cents/ ° F at 150 ° F to -5.20 cents/ ° F at 510 ° F. The integral reactivity effect of raising the SM-2 core water temperature from 103 to 510 ° F at 2000 psi and the water in the reflector coolant graph from 103 to 477 ° F at 2000 psi was -889.7 cents. The average measured material coefficients for U235 and B10 were 0.157 cents/g and 42.54 cents/g, respectively. Without the benefit of flux suppressors, the maximum- to average power ratio of 7.28 occurred at the top of the fuel section of control rod C (withdrawn to 7.14 in.), and a ratio of 5.28 occurred at the bottom of stationary element 43 and symmetric elements.
Research Organization:
Alco Products, Inc., Schenectady, NY (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); US Atomic Energy Commission (AEC)
NSA Number:
NSA-15-010419
OSTI ID:
4096320
Journal Information:
Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Vol. 9; ISSN 0029-5639
Publisher:
Taylor & Francis
Country of Publication:
United States
Language:
English