25th Anniversary Of Three Mile Island

fbform writes "March 28, 2004 is the 25th anniversary of the Loss Of Coolant Accident (LOCA) at the nuclear power plant on Three Mile Island, Pennsylvania. It's a good time to reflect on the impact it has had on our nuclear safety policy and interface design in general."

Comments

Shame

[colinramsay]

It's a shame that incidents such as this have contributed to the overall bad image of nuclear power. There is still a lot of potential which will probably never be revealed because the public at large are scared of what could happen if something went wrong.

The truth is that modern techniques could probably make nuclear power an extremely safe alternative.

Re:Shame

[Zeinfeld]

It's a shame that incidents such as this have contributed to the overall bad image of nuclear power.

It is a shame that sloppy and incompetent management by the nuclear power industry has created an entirely justified bad image.

The big lie told about three mile island was that the design is 'failsafe'. As a matter of definition it is not, no light water reactor design is. Failsafe means that if something breaks it breaks in a safe way. Three mile island had redundant safety systems, that is not the same thing.

The truth is that modern techniques could probably make nuclear power an extremely safe alternative.

The truth is that the better designs of forty years ago could have made safe nuclear power. The CANDU heavy water system is genuinely fail-safe. The coolant doubles as the moderator. That means if you loose one you loose the other and the reaction is halted.

Today there are vastly better designs, like the pebble bed reactor that MIT and others have been looking at.

The real problem is not technical, it is political. The concerns about nuclear power are completely justified. The nuclear industry has lied and deceived in the past. In the UK there was a long history of accidents, coverups and blatant deception. The true economics of nuclear power only became apparent after the Thatcher government tried to privatise nuclear power. When the books were opened it turned out that nuclear power had been vastly more expensive than claimed - and there are still the costs of decommissioning the plants.

Research into new types of nuclear reactor are required for many reasons. Even the idiots who ignore global warming see that energy reserves are running low. If we do not start looking at better nuclear options now we may end up being forced into repeating the light water mistake.

Re:What surprises me...

[Anonymous Coward]

With better engineering of measurement tools the whole thing would never have happened.
You have no idea buddy... take a look at the Presidential Report. Your above-included description lacks many other key elements that contributed to the factor. The failure that you list in (1) was most probably caused by cleaning the scrubber - the device that removes assorted crap from the incoming water into the secondary system. Unfortunately the scrubber regularly deposited large amounts of thick resin in the feedwater line. This resin is highly resiliant to chemical attack and needs to be cleaned away using a high pressure water hose. The control valve for the feedwater system works on pressurised air, and the cleaning process forced water and resin into the control system, resulting in a half open "8" (one of the valves, there's a complementary valve called a "12"). So the failure here was operational - Metropolitan Edison chose a poor method of cleaning.

There existed a secondary feedwater system, but unfortunately the operators had left the "8" of the secondary system closed (as mentioned in step 6). They didn't see the light telling them it was closed, as it was covered by a maintenance tag. If no stupid cardboard-tag based maintenancy strategy was used then they would have seen. The failure here was operator error/poor operational specification.

The operators didn't know that the PORV (pilot operated relief valve) was stuck open, and made assumptions about its behaviour. There was an emergency PORV-valve, known as a block valve. The operators didn't close this, despite the fact the drain temperature for the containment tank was over 2800 degrees farenheit, while normal operating temperature was in the range of 200. During a conference call with the senior Met. Ed. engineers they asked if this valve was closed. One of the operators said "yes", then covered the phone mouthpiece with his hands and shouted to the other engineer to close it. The failure here? Operator error and a terrible corporate culture that resulted in operators lying to senior engineers.

there's a shitload more problems with TMI, but to blindly say that this could have been solved by better engineering practice? No, you sir, are talking shit. A large number of the failings were operaional/human/organisational and outside the scope of any engineers ability to deal with.

Re:Stop and pause

[djh101010]

With the posting of the Chernobyl story yesterday, this should make some of us pause and think about what could have been...

Very true. It allows us to realize how fortunate it is that our engineers rejected the open-pile design which caused Chernobyl to be so dangerous. It also makes me thankful that, due to the skillful design, the TMI incident is a disaster only in the terms of public-relations among those who don't understand, or want to understand the science.

I don't think that anyone who isn't rabidly anti-nuclear power would consider these to events to be anywhere near equivalent. It says a lot for the systems that, despite the chain of human and mechanical failures, the incident at TMI was limited to such a small environmental impact. That wasn't by luck, it was by design decisions, choosing a much safer way to use nuclear energy to create power.

Bringing Chernobyl into the context of TMI shows that the person doing so either doesn't understand the science, or is trying to use fear of Chernobyl to convince others who don't understand the differences.

Re:Nuclear power industry not safe.

[orthogonal]

No, it [nuclear power] is not safe

Nothing is completely safe. Thing is, the alternatives - the real, viable alternatives -- to nuclear power are even less safe.

You may recall the recent FDA advisory warning pregnant women and children to limit their intake of several types of fish because of mercury contamination in those fish.

The FDA guidelines call for children and pregnant women -- and women who "may become pregnant" to abstain completely from shark, swordfish, king mackerel, or tilefish, and to limit intake to six onces of albacore tuna a week.

What you might not have heard is that the panel that made the recommendation contained two members who were former lobbyists for the fishing industry -- or that another member, a scientist, not a lobbyist, resigned in protest because he believes that even six onces a week of albacore tuna is dangerous, and that that recommendation was only made because of industry lobbying.

What you also might not have heard is that the primary source of mercury in fish is from "mercury rain" -- and the primary source of mercury rain is from coal fired power plants .

As it happens, the EPA is retreating from plans to more closely regulate mercury pollution from power plants, and "just coincidently" some of the language justifying that retreat is word-for-word the same as language in utility company memos.

So on the one hand, the fishing industry influences the FDA to soft-pedal its warnings to children and pregnant women, and on the other hand the power industry gets the EPA to continue to allow pollution.

And this is not to mention the other dangers of coal: despoiling the environment by digging it up, despoiling the air with smog when it's burnt, giving miners black-lung, etc.

I grew up a few miles from Three Mile Island, and I was still there when the accident happened, and I'll take clean nuclear power any day. Even in the worst case, we can contain a nuclear plant accident -- but we can't contain an ocean of mercury contaminated fish.