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

Friday, April 8, 2011

Friday morning update...

There are no new details to report on any of the nuclear plants in Japan which were affected by the most recent earthquake. See previous posts on this blog for effects of this quake. However, it might be prudent to report that all plants do have offsite power available even if not through all normal high tension lines. The only nuclear related site still without external AC power is the fuel reprocessing plant we mentioned earlier, at least so far as the best available recent reporting.

Conditions at Fukushima Daiichi are as before. Nitrogen injection to No. 1 plant continues... this may take up to a week total. The recent press releases are again including TEPCO estimates of percentage of core damaged for each of the plants with cores installed; the percents of core damage given are No. 1, 70%; No. 2, 30%; No. 3, 25%.

Now, moving over here to this side of the ocean for a moment.... there is actually a story running in Japan that a US Congressional subcommittee has released a document talking about Station Blackout at the Peach Bottom site, in Pennsylvania, and how it might not survive this either just as the Fukushima plants did not. This report, which I have yet to see but in all likelihood have already read elsewhere, is also very likely from the 1980's. That's right. It's probably that old. Such concerns have been addressed here for many years.

From the beginning, it was known (and much of the public now realizes, too) that nuclear plants still require electrical power even with the reactor shut down. Normally the reactor itself is providing all the power needed to run the plant, or at least it's providing steam... this is why there are two electrical ratings for nuclear plants that you'll read and find bandied about, namely MWe and MWe (net.) The first is all the electric power a plant generates; the second is all the power that gets sent to the grid for use in businesses and homes, and is lower. It's lower because the plant load (some call it parasitic load) to run all the plant equipment is deducted. All plants had some type of standby diesel generators to supply plant loads in case of plant shutdown and LOOP (Loss Of Offsite Power.)

Even though from the very beginning this was recognized as a problem, it was not very seriously addressed legislatively at first. The WASH-1250 report mentions Station Blackout as being in the intermediate or middle of three categories of likelihood when it comes to events that can cause core damage; this was published in draft form (apparently never widely distributed though) by the AEC in July, 1973. For those with a copy, see page 5-3. However, not too much more was done at least from a legislative approach until the NRC identified SBO as an "unresolved safety issue" in 1980. From that date, Oak Ridge National Laboratories began what became a long and intensive study of SBO events at BWR plants. The SBO directive issued what is known as the SBO Rule in 1988 which led to owner-operators greatly increasing both availability and reliability of onsite (that's either diesel generator or some other type of generator) capacity. Even though the events in Fukushima will lead to further reviews here, the rolling out of one report is by no means enough to make US citizens afraid of BWR reactor plants given the information ... FACTS ... that I've just presented to you.

6:10 AM Eastern Friday 4/8


  1. Will, can you try putting commas into your list of labels (tags)? That should make them seperate tags rather than one giant tag.

    Thanks for the continuing updates.

  2. Good report and true enough, but FACTS that have to get OUT to make a diffference! It would be very interesting to know what would happen if you submitted this report to various media outlets and see the answers you'd get.

  3. Actually, jimwg, there are a number of "big media" that I already know for sure are reading this blog. Whether or not they choose to INCLUDE what is written here is up to the writers... and the editors and publishers. But I know they're looking.

  4. I'm all in favor of FACTS but while you are at it how about including the fact that many US plants have less battery backup than Japanese plants (4 hours vs 8 hours). How about the fact that no backup power at all is required for US spent fuel pools.

    The debilitating factor is always the one that they failed to consider or under rated the risk. With very similar plants here in the US already 40 years old being given 20 year extensions this will happen here. Nuclear is a sucker's bet.

  5. @david: You've been reading Newsweek and watching CNN again, haven't you? So then what is the status of EDG capacity when compared with Japanese plants given the now-twenty-year-old NRC SBO rule? You don't need batteries if you have diesels.

    Since when are spent fuel pools on a totally separate power grid from the reactor plant? They're not. They're on the SAME SWITCHBOARDS. Moreover, when you say "backup power for spent fuel pools" what exactly are you saying? What backup power is needed? The same circulating water pumps that transfer decay heat from the reactor plant to a river, say, also transfer heat load from the spent fuel. There's no separate electrical system. That means that in SBO the entire plant is on the diesels, including every subsystem and that means spent fuel pool cooling as well.