NEI Nuclear Notes

Several news articles late this week have reported that Japan’s Fukushima Daiichi nuclear plant may be in “cold shutdown” by mid-December. Although the reports are mostly accurate, there is a difference between the traditional “cold shutdown” of a nuclear plant and what is happening at Fukushima. First, what is cold shutdown? The U.S. Nuclear Regulatory Commission defines it as: The term used to define a reactor coolant system at atmospheric pressure and at a temperature below 200 degrees Fahrenheit following a reactor cooldown. In non-nuclear speak, it basically means the conditions within the nuclear reactor are such that it would be impossible for a chain reaction to occur. This term usually comes into play whenever a reactor is shut down periodically for refueling or for the final time prior to the long-term before it is decommissioned. When a reactor is in cold shutdown, the reactor pressure vessel (RPV) can be safely opened with great care and additional water is adde...