APR: your source for nuclear news and analysis since April 16, 2010

Sunday, October 9, 2011

New video: Fukushima Daiichi cooling water injection

TEPCO has released its third video in the series which is intended to inform the public about operations and conditions at the Fukushima Daiichi site. This video is now up at the APR YouTube Channel... link below.

TEPCO is to be commended for its transparency vis a vis the content of these videos; the new video is perhaps the most graphic yet in terms of what MIGHT happen if cooling water injection is interrupted for various periods of time. Even the worst case scenarios (which frankly are only remotely likely, on the order of probability of the tsunami that caused the accident in the first place) are examined and described. A few notes may be helpful to non-nuclear readers and viewers, however.

-The equipment being employed on site and which is described in this video is wholly non standard. The arrangements of equipment external to the plants in terms of tankage, hoses, mounted pumps and also fire engines and diesel generators and pumps have been set up in stages over time since the accident in ever-improving layout, operation, redundancy and effectiveness. This should be kept in mind when viewing this video - in other words, that the possible scenarios are limited to Fukushima Daiichi Nos. 1 through 3 plants ONLY.

-In many places, TEPCO makes calculations or estimations which are clearly in error on the conservative side. As one example, TEPCO states that effects of metal-water reactions upon exceeding 1200C (in the unlikely event of prolonged feed interruption) are made using original core inventories even though it's proven that a large amount of the zirconium metal in the core has already reacted and thus is not actually available for further reaction. In this way, at every step of any process considering decay heat removal, estimates of the time required to react will be much shorter than actually required.

-When describing the dual fire engine flood feeding (core reflood) with two lines, TEPCO omits to indicate that one of the fire lines would feed through the feedwater injection line (feed sparger ring) while the other would feed through the core spray ring. At present, both are in use at all three reactors.

This video is very descriptive and outlines a number of possible but unlikely scenarios. TEPCO is clearly prepared for any further complications on site which would affect cooling of the damaged cores, and this video should calm a few of the most worried observers quite a bit.

APR YOUTUBE CHANNEL LINK - See "Fukushima Daiichi - Cooling Water Injection."

7:30 PM Eastern Sunday October 9, 2011

1 comment:

  1. Thanks for these. Very informative. They should also place more web cams around the facility to show more openess.

    James Greenidge