Reactivity Measurement on the Reflected Semi-Homogeneous Critical Assembly by Pulsed Neutron Technique

Journal Article · Tue Dec 04 04:00:00 EST 1962 · Nippon Genshiryoku Gakkaishi

DOI:https://doi.org/10.3327/jaesj.4.825· OSTI ID:4761625

Sumita, Kenji ^[1]; Kaneko, Yoshihiko ^[1]; Kurokawa, Riyosuke ^[1]; Park, Tae Wan ^[1]

---

1. Japan Atomic Energy Research Inst. (JAERI), Tokai (Japan)

Measurements are made of the prompt neutron lifetime and of the equivalent reactivity worths of control rods and the gap between two halves of the SHE-1 (Semi-Homogeneous Critical Assembly Core-1) by pulsed neutron technique. The decay constant α can be measured in the range from 7.19 to 147.7 sec^-1 within 2.1%. Here, the prompt neutron lifetime of this assembly is determined to be 1.21 ± 0.03 ms (assuming β_eff = 0.0067), and the equivalent reactivity worth of a Cd control rod to be 4.10 ± 0.13. However, the reactivity found from the value of α by the conventional formula, (α--α_c)/ α_c is found to have a larger error than experimental one below about ~9 or SHE-1, because the change of the value of k_eff/β_eff/1 with the degree of subcriticality is neglected. The theoretical validity of reactivity measurement in the reflected subcritical system by pulsed neutron technique is discussed.

• Research Organization: Japan Atomic Energy Research Inst. (JAERI), Tokai (Japan)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); US Atomic Energy Commission (AEC)
• NSA Number: NSA-17-013337
• OSTI ID: 4761625
• Journal Information: Nippon Genshiryoku Gakkaishi, Journal Name: Nippon Genshiryoku Gakkaishi Journal Issue: 12 Vol. 4; ISSN 0004-7120
• Publisher: Atomic Energy Society of Japan
• Country of Publication: Japan
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CADMIUM
CONFIGURATION
CONTROL ELEMENTS
CRITICAL ASSEMBLIES
CRITICALITY
ERRORS
HALF-LIFE
HOMOGENEOUS REACTORS
LIFETIME
MEASURED VALUES
MULTIPLICATION FACTORS
NEUTRON BEAMS
Nuclear Criticality Safety Program (NCSP)
PROMPT NEUTRONS
PULSES
REACTIVITY
REACTOR CORE
REFLECTORS
RODS
ZONES