Monday, February 6, 2012

Cold shutdown getting less cold

http://ex-skf.blogspot.com/2012/02/fukushima-i-nuke-plant-reactor-2-rpv.html


The data is not entered yet in TEPCO's plant parameter page. The last measurement of the location - RPV Bottom Part - is at 11AM on February 5, at 68.6 degrees Celsius (as reported in the previous post).

So it went up 3.1 degrees Celsius in 5 hours, the sharpest rise yet since February 1.

From Jiji Tsushin (8:16PM 2/5/2012):
2号機原子炉、70度超に上昇=冷却水増加で対応-福島第1

Reactor 2 RPV temperature at Fukushima I Nuke Plant risen above 70 degrees Celsius, TEPCO increases water injection

東京電力は5日、福島第1原発の2号機原子炉の圧力容器底部にある温度計のうち、状況判断の基準とする西側の1カ所の温度が同日午後4時に71.7度に上昇したと発表した。1日午後11時時点の52.0度から大幅に上昇しているが、同じ高さにある別の2カ所の温度計は45度程度で安定している。東電は基準温度計の不具合の可能性を検討する一方、冷却水の注入量を毎時1トン増の同9.6トンにして様子を見ている。

TEPCO announced on February 5 that one of the thermometers on the bottom of the Reactor Pressure Vessel of Reactor 2 at Fukushima I Nuclear Power Plant registered 71.7 degrees Celsius at 4PM. The location is one of several temperatures that [the company uses] to gauge the situation. The temperature there has risen sharply since it registered 52.0 degrees Celsius at 11PM on February 1. However, at two other locations at the same height, the temperatures remain steady around 45 degrees Celsius. TEPCO is considering the possibility of instrument failure, but in the meantime has increased the amount of water injected into the reactor by 1 tonnes, to 9.6 tonnes/hour and see if it makes difference.

事故後の状況を踏まえ、経済産業省原子力安全・保安院が認可した新たな保安規定では、基準温度計の温度が80度に達するか、冷却水量を1日1トン超増やす場合は「運転上の制限逸脱」となり、地元自治体に通報する。東電は100度以下の「冷温停止」維持のほか、溶融燃料が再び核分裂連鎖反応を起こす「再臨界」防止のため、炉内ガスの分析も急ぐ方針。The new safety regulation approved by the Nuclear and Industrial Safety Agency after the March 11, 2011 accident specifies that it is considered "deviation from operational limit" when the temperature taken at the standard locations reaches 80 degrees Celsius or the amount of injection water is increased by 1 tonnes [per hour?] per day, and the local municipalities have to be notified. TEPCO is planning the analysis of the gas inside the reactor in order to maintain the "cold shutdown state" where the temperature remains 100 degrees Celsius and lower and to prevent "recriticality" where the melted fuel starts nuclear chain reaction.
I wonder if the local municipalities have been notified.

No comments:

Post a Comment