Application of the post-boiling-transition standard to licensing analysis

Shinya Mizokami, Hideya Kitamura, Yoshiro Kudo, Seiichi Komura, Yoshifumi Nagata, Shinichi Morooka

Research output: Contribution to journalArticle

Abstract

To ensure fuel integrity, light water reactor cores are designed to avoid the onset of boiling transition (BT) inside the fuel assembly that leads to a deterioration of the heat transfer characteristics and subsequent excessive rise of the fuel-cladding temperature in the anticipated operational occurrences (AOOs). However, some boiling water reactors' AOO events result in immediate scram or suppression of the reactor power due to an increase in the reactor coolant void fraction. Recent studies show that a short duration of dryout inside the fuel assembly only leads to a small rise in the fuel-cladding temperature and thus does not pose a threat to fuel integrity. Many tests on BT and an improved comprehension of its mechanism have led to the development of a methodology to appropriately assess the fuel-cladding temperature after BT has been reached. The Standards Committee of the Atomic Energy Society of Japan has therefore proposed a cladding temperature criterion after BT. Applying the post-BT standard enables the value of the operating limit minimum critical power ratio (OLMCPR) to be decreased by allowing for a short duration of dryout. We calculated the fuel-cladding temperature and dryout duration in the load rejection condition without a bypass event. The calculated results show that both the fuel-cladding temperature and dryout duration meet the post-BT standard in the case of a small OLMCPR, which is determined by the loss of feedwater heating. This enables a more efficient reactor core to be designed by applying the post-BT standard to licensing analysis. The possibility of applying a post-BT standard is demonstrated from the results of this work.

Original languageEnglish
Pages (from-to)105-117
Number of pages13
JournalNuclear Technology
Volume152
Issue number1
Publication statusPublished - 2005 Oct
Externally publishedYes

Fingerprint

licensing
boiling
Boiling liquids
reactor cores
Reactor cores
integrity
Temperature
temperature
assembly
boiling water reactors
occurrences
light water reactors
power reactors
Boiling water reactors
Light water reactors
Void fraction
bypasses
coolants
nuclear energy
deterioration

Keywords

  • Boiling transition
  • Dryout
  • Rewet

ASJC Scopus subject areas

  • Nuclear Energy and Engineering

Cite this

Mizokami, S., Kitamura, H., Kudo, Y., Komura, S., Nagata, Y., & Morooka, S. (2005). Application of the post-boiling-transition standard to licensing analysis. Nuclear Technology, 152(1), 105-117.

Application of the post-boiling-transition standard to licensing analysis. / Mizokami, Shinya; Kitamura, Hideya; Kudo, Yoshiro; Komura, Seiichi; Nagata, Yoshifumi; Morooka, Shinichi.

In: Nuclear Technology, Vol. 152, No. 1, 10.2005, p. 105-117.

Research output: Contribution to journalArticle

Mizokami, S, Kitamura, H, Kudo, Y, Komura, S, Nagata, Y & Morooka, S 2005, 'Application of the post-boiling-transition standard to licensing analysis', Nuclear Technology, vol. 152, no. 1, pp. 105-117.
Mizokami S, Kitamura H, Kudo Y, Komura S, Nagata Y, Morooka S. Application of the post-boiling-transition standard to licensing analysis. Nuclear Technology. 2005 Oct;152(1):105-117.
Mizokami, Shinya ; Kitamura, Hideya ; Kudo, Yoshiro ; Komura, Seiichi ; Nagata, Yoshifumi ; Morooka, Shinichi. / Application of the post-boiling-transition standard to licensing analysis. In: Nuclear Technology. 2005 ; Vol. 152, No. 1. pp. 105-117.
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