Long blackouts may pose risk to Pa.'s nuclear reactors

[jpak]

http://www.poconorecord.com/apps/pbcs.dll/article?AID=/20110329/NEWS90/110329669/-1/NEWS

PHILADELPHIA (AP) — Though the odds are extremely remote, Pennsylvania nuclear reactors, including those near Lancaster and Beaver Creek, could be vulnerable to radiation leaks if their power were knocked out for days, an Associated Press investigation has found.

The risk exists for all U.S. nuclear reactors if there are no other means to keep the reactors cool, but some are more susceptible than others, according to the AP investigation, conducted in the wake of radiation leaks at Japan's Fukushima Dai-ichi nuclear plant.

One simulation presented by the Nuclear Regulatory Commission in 2009 showed that it would take less than a day for radiation to escape from the Peach Bottom Atomic Power Station outside Lancaster if there were a blackout and the reactor couldn't be kept cool. That atomic power station has reactors of the same older make and model as those releasing radiation in Japan.

While regulators say they have confidence that measures adopted in the U.S. will prevent or significantly delay a core from melting and threatening a radioactive release, the events in Japan, which was stricken by an earthquake and tsunami, raise questions about whether U.S. power plants are as prepared as they could and should be.

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[MineralMan]

1. Then, lets shut them down systematically and safely, and leave

them shutdown until they can be decommissioned. That's my suggestion.

[jtrockville]

10. ^ Like

[lob1]

2. I have serious doubts about both plants in California.

I live outside L.A., smack between the two. And if we had to evacuate L.A., we couldn't. Our freeways and roads can't handle the friday night traffic out of town. If everyone in L.A. tried to leave at once, no one would go anywhere. The plants evacuation plans can't work. It's like BP's plan to fix a blow out in the gulf.

[buddysmellgood]

3. They should have nat gas peak generators near all nukes.

[caraher]

4. They had diesel generators at Fukushima

It's not that they didn't know having standby power was a Good Idea. It's that they didn't do anything intelligent to protect them from the same event that caused the disaster in the first place ("let's see... generators on low ground? Tsunami threat? Sounds like a plan...")

Diesel may be better bet than a natural gas plant for emergency operation of cooling systems because it's probably easier to store the fuel onsite. You don't want to be vulnerable to pipeline failures on top of everything else.

[buddysmellgood]

8. I was thinking compressed gas would hold more fuel than diesel, but I don't know. Good point about

gas lines.

[Throckmorton]

9. The comparison is as follows:

Diesel Fuel 139,000 BTUs per gallon.
Liquefied Natural Gas 84,000 BTUs per gallon

Or diesel fuel has about 60% more energy per gallon, than LNG.

[buddysmellgood]

14. I read that a number of U.S. reactors installed duplicate

diesel generators some distance from the reactor. This was a 9/11 response.

[Throckmorton]

16. Not 9-11, Station Blackout Rule.

The new rule requiring SBO mitigation equipment, most plants used stand alone diesel generators, was written in the late 1980's as I recall.

[TheWraith]

15. It's not that the didn't consider the possibility of natural disaster.

It's that they designed it to withstand a smaller event, and gambled on the fact that the odds of this magnitude of disaster happening was something like once every thousand years.

Unfortunately, odds only indicate probability, not possibility.

[CC]

5. Oh Peachbottom....

the plant that the guys in the control room were caught sleeping while on duty in. Repeatedly. Had to have new rules written so that doesn't happen again. :eyes: I won't go into how they left everyone sitting in the cafeteria when warning alarms went off...because alarms couldn't be heard in the cafeteria. I know people that work in there, they come from the same population as the rest of us and have the same percentage of very good, good, fair, bad and downright lazy workers as the rest of the population. The human element scares me the most. (As I look at the 10 mile radius siren in front of my house.)

[Fledermaus]

6. "mini-Tunguska" impacts are the most frequent, happening once every few decades

What will happen when one of these things hits North America or Europe? How would we keep power to all the nuclear power plants?

What would have been the consequences if 2004 AH had actually hit the Earth instead of passing by at a distance of 50,000 km?

Stimulated by recent media attention on asteroids AL00667 and 2004 FH, there has been a lot of speculation about the damage a small asteroid (of roughly 30 m diameter, kinetic energy about 1 megaton) might cause if it hit the Earth. This is an important question, since such "mini-Tunguska" impacts are the most frequent, happening once every few decades. There has been a lot of confusion on this point, however. Some have assumed that if it "disintegrates in the atmosphere" it will do no harm, neglecting the fact that air-bursts near the surface are exceedingly destructive, a fact well known to the designers of nuclear bombs. At the opposite extreme, some assume that an explosion of 1 megaton energy taking place anywhere in the atmosphere is a major hazard, but this is true only if the explosion occurs within about 10 km of the surface. Either conclusion - that there is no danger or that such an impact would be equivalent to a major nuclear strike - misrepresents the real situation.

http://www.spaceref.com/news/viewsr.html?pid=12344

[Yo_Mama]

7. Sigh

The article kind of forgets about the backup generators.

I posted this link somewhere else in response to a similar article, but power loss of more than a week has occurred in the US in similar circumstances to Japan's current tragedy. Katrina knocked out power over 100 miles inland and across hundreds of miles of coast. And there is a nuclear power station, Waterford 3, about 25 miles out of NO right on the coast. At the time it was a big issue. They shut down suddenly without time to go into cold shutdown because of the expected storm surge (which did top the levees).
NRC Waterford page:
http://www.nrc.gov/info-finder/reactor/wat3.html

A summary of the incident:
http://www.google.com/url?sa=t&source=web&cd=2&sqi=2&ved=0CB4QFjAB&url=http%3A%2F%2Fhome.engineering.iastate.edu%2F~jdm%2Fkatrina%2FData%2FElectricity%2FElectricity%2520Generation%2FNRC%2520reports%2520on%2520Waterford%2520nuclear%2520power%2520plant.doc&rct=j&q=Waterford%20nuclear%20plant%20Katrina&ei=tomSTfiPMcLUgQf00pgZ&usg=AFQjCNEzV745gMbKnZI9pGP8Dxvang-bbQ&cad=rja

Note the backup diesel generator.

[Throckmorton]

11. The Station Blackout (SBO) Scenario

In this scenario it is assumed that all AC Power is lost, (actually not all AC power is lost, just the high energy stuff, the instrument busses are powered from inverters on the plant batteries) and all of the station diesels fail to load or cannot remain loaded due to cooling issues.
The Cat-1 diesels are cooled using service water, which is provided by pumps in the intake structure.
The diesels can only run for a minute or two without this cooling water, or they overheat and fail.
Many stations in the US have added an additional diesel generator, or two, that are self-contained and air cooled to help cope with this issue.
In BWR's, the low pressure safety injection pumps are run by small steam turbines, that take a suction on the suppression pool to provided the reactor with emergency core cooling in an SBO scenario.
Likewise, US PWR's have a steam driven Auxiliary feedwater pump that takes a suction on the condensate storage tank to feed the Steam generators in the SBO scenario. The reactor is cooled by reflux boiling in the Steam Generators until shutdown cooling can be established when AC power is restored.

The problem is, that in this case, in addition to the diesels being flooded out and the fuel tanks destroyed, I believe that the service water pumps were also destroyed by the Tsunami. This would have rendered the diesels unavailable in short order. Unavailable is fancy nukespeak for broken really bad.

[bananas]

12. "Unavailable is fancy nukespeak for broken really bad."

k&r

[Turbineguy]

13. Nukespeak classic:

"Prompt Critical Excursion"

It's what happened at Chernobyl.