Analysis of a main steam isolation value closure anticipated transient without scram in a boiling water reactor

Journal Article · Fri Dec 01 04:00:00 EST 1989 · Nuclear Technology; (USA)

OSTI ID:6954875

Liaw, T J; Pan, C; Chen, G S ^[1]; Huiue, J K ^[2]

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1. National Tsing Hua Univ., Hsinchu (Taiwan). Dept. of Nuclear Engineering
2. Taiwan Power Company, Taipei (TW)

Anticipated transient without scram (ATWS) could be a major accident sequence with possible core melt and containment damage in a boiling water reactor (BWR). The behavior of a BWR/6 during a main steam isolation valve closure ATWS is investigated using the best-estimate computer program, RETRAN-02. The effects of both makeup coolant and boron injection on the reactor behavior are studied. It is found that the BWR/6 behaves similarly to the BWR/2 and BWR/4. Without boron injection and makeup coolant, the reactor loses its coolant inventory very quickly and the reactor power drops rapidly to {approximately} 16% of rated power due to negative void reactivity. With coolant makeup from the high-pressure core spray and the reactor core isolation cooling systems, the rector reaches a quasi-steady-state condition after an initially rapidly changing transient. The dome pressure, downcomer water level, and core power oscillate around a mean value; the average core power is {approximately} 15%, which is approximately equal to the power needed to heat and evaporate the subcooled makeup coolant. Lower boron concentrations in the core tend to complicate reactor behavior due to the combination of two competing phenomena: the negative boron reactivity and the positive reactivity caused by a void collapse.

• OSTI ID: 6954875
• Journal Information: Nuclear Technology; (USA), Journal Name: Nuclear Technology; (USA) Vol. 88:3; ISSN 0029-5450; ISSN NUTYB
• Country of Publication: United States
• Language: English

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ACCIDENTS
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