I believe I speak for a large number of readers of this forum, and I am certain I speak for myself when I say that your opinions, sharing of your knowledge and your humor are well thought of and valued here.

Because of this regard and because of your stated knowledge of things nuclear, I am sure that your comments, opinions, and particularly your knowledge in the nuclear power field would be most welcome in regards to the posting to the effect that a nuclear power plant requires something between 4 and 6 months of cooling to remove residual heat from the reactor core after the plant has been "scramed".

I personally value your opinions and comments in these areas at the same level as those of Mr. Cowles and Mr. Mills, although I tend to give yours greater credibility.

-- Hardliner (searcher@internet.com), October 17, 1998

Answers

Thank you for the compliments, I appreciate them very much. Hopefully, I'll continue to justify your trust and keep trying to be as accurate as possible. Feedback helps improve things, so let me know if you have recommendations.

Now, feedback may not mean I'll get any better at spelling things, but certainly I'll be able to mispell words faster if I ever learn how to type...

About nukes and the July 1999 deadline for Y2K compliance. Please, first, let me get some specific (detailed) references from the NRC offices here, and from the INPO offices about Y2K, before I speak about the specific "regulations" you're talking about, and about the embedded chips in cotrol circuits/safety circuits in the power plants. I'd rather confirm some estimates and look up a few things before I shoot myself in the toe.

INPO is a "certification and training" organization sponsered by the industry, they are like the NRC, in that they serve in a QA and improvement role, but compliance is "voluntary" rather than "statutory" as in the CFR (Code of Federal Regulations). However, violations are taken equally seriously.

Note carefully, as shown in the other threads about nuclear shutdowns, that the deadline mentioned is a "bureacratic" one, not a physically derived or inherent in the nuclear physics involved in running a power plat. Reading between the lines of the other quote, it appears that the regulators understand that 100% compliance cannot practically be demonstrated prior to actual implementation and testing of each program. That is, they want a wide operating margin (chosen to be 6 months) before the actual crisis date. If problems are found, if implementation is delayed during testing, if operations can be done consistently and safely (while a certified backup (the current operating systems) are available), then the plant is in a more safe condition. That is their mandate - plant safety. So all their actions (at the NRC level) are geared that way.

So the six month margin sound like it was chosen to maximize the oeration time after implementing and testing the new systems. It also is late enough to allow completion of the work. Remeber, the nuclear plants began before most other companies, and certainly before any other utility systems.

In this, they (the nuclear plants and utilties) are much further along than anything else out there. Not done, but further along. "More likely to get done than anything else" might be the most "positive" spin you can put on the current plans.

The quoted reference also apparently allows waivers (partial certs, or restricted certification, most likely) based on conditions. Makes sense. Now, from the national NRC headquarters, nobody can tell exactly what schedules willl be met by which uitliteis, and what waivers will be needed, by the middle of next summer.

But, any plant operators not able to demonstrate Y2K compliance by the deadline (within this margin "allowed" by some sort of waiver), can also be reasonably expected not to complete the remaining programming, "debugging", testing, re-programming, re-training, implementation and installation, and still have enough "operating" time before the deadline. So anybody NOT able to finish by July 1999 has no business trying to "hurry through" emergency solutions to meet a later deadline. The problems are too important to allow that.

Thus, the deadline was set early to give the biggest practical safety margin for operations and safety, not for cooling the plants.

Nuclear plants in general with respect to Y2K?

I've lived I respect their power and capability, and know what parts can kill (depending on the time invovled, different things are dangerous to different levels at different times), what parts are "dumb steel and concrete" and what parts are literally beautiful in their nuclear physics, design, simplicity and safety. He's possibly scared to death of the very idea of the thing, and doesn't know enough to know where the "safe" limits are. Worse, he (and many others, don't want to understand.

For example, nuclear plants are among the first things every story about Y2K used to talk about, and they are perhaps the only part of the national grid I consider likely to be operational.

My opinion: you are more likely get high voltage power to the "end" of the distribution yard at a nuclear plant than any other place in the country.

The problem will be geting these volts downstream to the public.

Cooling the plant after shutdown? Cooling the things down is a little like radiation, there are degrees of difficulty involved. What I consider reasonable and practical conditions in a power plant (when I walk around in them, or build them, or live next to one, or test them, or inspect them) probably isn't what a reporter for the local paper would consider pracical or even rational. A reporter wants simplistic, first grade answers to questions that are based in physics.

So let me give you a "quickie" physics lesson to explain it; I figure you'll understand better that way. The plant generates heat while critical, this heat is what drives the turbine. Groovy. Same things happens in any steam power plant.

Difference is: in a steam power plant, when the burner turns off (like when there is no oil, or no coal, or no natural gas in the distribution network), the residual heat in a convential plant quickly goes away. Like your car engine, the steel and water cool down at a measureable rate to room temperature. Say, in 18 to 24 hours, the pipes are cool enough in many areas to work on or repair. If cool water is flushed through them, they are also immediately ready to be worked on (safe to touch without getting burned.)

In a nuclear plant, about 2-3% of the "running" heat comes from the decay of radioactive daughter products in the core from earlier fissions. So immediately after a "scram" (shut down), a 1000 megawatt plant still is CREATING heat: assume this is about 30 megawatts of thermal energy that must be disappated. The fissions have stopped, but the decay heat is still being created.

If this decay heat is not removed from the core by passing "cooler" water through the core, then, after a period of time (several hours in most scenarios), and if the water is not repalced (if there were a break in the pipes), the water originally covering the core may boil off. The core continues to heat up, but it is exposed to air, and damage may occur. [This is a VERY short discription of part of what happended at three Mile Island.]

So the key to shutting down a nuclear plant is to keep the core covered, and to keep emergency power and emergency water always available (via backup generators, alternate pumps, alternate tanks, alternate supplies, alternate controllers, etc.) All these backups are covered, and recovered through emergency and routine training, which is also a readon to expect better relaibility from a nuclear plant than a conventional one.

Nobody likes to work around decay heat, it is a problem I hope will go away when fusion plants come on line. But the nice thing about decay heat is that the heat load goes down expontentially over time after shutdown. After a few hours, say for example, 12 hours, the energy release rate is half its initial rate. After another twelve hours, it is 1/4 the original rate. This is still a lot, but it keeps decreasing.

The same thing happens with the radioactivity in the plant: but at a different rate depending on which isotope, what power levels, what power history, etc.

Using this assumption, after 10 days the decay heat is still being created, but it is being created at only a small fraction of the initial rate. After a while, you can see that the outside of the containment building is receiving more thermal energy from the sun than it is being created from the reactor core inside.

Bottom line, the thing is still releasing heat "forever"- but not enough to worry about in a Y2K scenario.

For example, during every refueling shutdown, the cover of every reactor can be removed and the core exposed for refueling after a very short amount of time. [All this exposure happens inside the containment building, above a "swimming pool" type of open tank.] Assume the worse possible Y2K case of long term shutdown for a plant in a maintenance shutdown: get a fire truck and refill the "swimming pool". The core remains covered, the plant remains safe and can be restarted without incident.

Note to "the powers that be": yes, there are backup systems, safety systems, monitors and cooling systems in place anyway for the fuel pool. [I offer "refilling the pool" as an example of how common solutions can be applied to show the small degree of the problem.]

So what a politician or reported talks about as a "problem" should not (and I will shout here: [in this PARTICULAR case, and ONLY in this SINGLE case of pwer plant cooling]) be worried about for Y2K.

That leaves 9,999,999 things left that will cause problems.....

-- Robert A. Cook, P.E. (cook.r@csaatl.com), October 18, 1998.

Thanks for taking the time to write this response. It has helped to put some additional perspective on this issue. I can't say my concerns with this issue are completely alleviated but I'm just tiny bit better educated on it now.

Understand, my concern is personal because I live very close to one of these facilities. I've never been overly concerned with meltdown/radiation release scenarios. But it seems prudent to re-evaluate my reasons for confidence at this time in light of Y2K issues/potentials. No, I don't believe the folks that run the local facility are morons or that they are not prepared to handle most situations. It's just that, from a Y2K perspective, several things may be going wrong in succession.

I'm confident enough in the safety of these facilities to have lived next to one for 10 years without fear. But I will say that the one thing that has always bothered me is that no insurance company will cover losses related to accidents which occur at such facilities and our legislature (at least in the US) has severely limited the liability the operators of these facilities would face should a serious accident occur. In short, there exists a 'get out of deep doo-doo free' card for insurance companies and nuclear plant operators. Should my property become uninhabitable due to even a very limited containment breach, my insurance company has made it absolutely clear that they won't be there to help and neither will the plant operators. My only real comfort here is that my neighbor across the street is a senior level engineer at the facility and would be facing the same situation as me.

Thanks again. Arnie

-- Arnie Rimmer (Arnie_Rimmer@usa.net), October 18, 1998.

This situation has created an implied disaster relief "contract" between the federal government and the individuals and businesses in the area around a nuclear plant to assume the costs of that kind of massive relocation/cleanup. Smaller ones (more likely to occur) would be covered by the current insurance up to the limits you mentioned.

Not what I want (more federal power or influence), but it is more or less the "status quo." Nobdy wants to talk about it though as "policy", but consider the consistent 50 year response to regional problems like floods or tornadoes.

Ceing close to a power plant can't immediately assure you of power (since the distribution is under separate control systems), but electrons have to start somewhere before they can go someplace else. So you are more likely to get power restored (or keep it longer) thatn more remote users in the country.

Or vice-versa - the most 'remote" user might be the one downtown, competing against millions of other (less-prepared) panicked users all fighting for the same electrons. That person has no choice: he or she is handcuffed to the same wires that everybody else has. Either everybody there has power or nobody does.

So what does a downtown shopowner do?

Ref: The LA riots where owners had to defend their homes and livelihood. The police retreated away from where they were needed beciase they were intimidated by the looters.

-- Robert A. Cook, P.E. (cook.r@csaatl.com), October 18, 1998.

Robert, brilliant insight into nukes. Must take plenty of IQs.

-- Richard Dale (rdale@figroup.co.uk), October 19, 1998.

I am humbled by your praise, but must gracefully decline.

If being a "nuke" teached you anything (outside of the technical fields themselves), its that in every field, in every topic, at any time, there is always an expert who knows more about the given subject than you do.

See, for a nuclear engineering degree, you get about equal mixes of nuclear physics, math, electrical engineering, electrical control theory and design, mechanical design, thermodynamics and heat transfer, fluid transfer, mechanical design, civil design, structures and materials, and nuclear/radiation operations and practice.

(Repeat all the above for the Navy's nuclear power school, then repeat engine room design/operations/testing/utilties systems design and operation durign submarine school.) Repeat all above and add sub operations/defense plus communications and radio operations (satellites, communcations, electrical controls, sensors, weapons, etc.) during submarine oeprations and training. Do it all again during construction, repair, scheduling, rebuilding, refueling, fixing the stupid things.

But durign the whole time, there is always somebody who is doing the welding, or the fixing, or the "tweaking" (or the typing) or the cooking or designing or the programming or whatever. All the good "nuke" can do is coordinate everybody. There is always somebody who design a concrete wall better and faster than you can, or order the steel rebars, or setup the plywood form holding up the wet concrete, or getting the nails for the plywood, or building the scaffolding, or pouring the concrete.....

So the combination of all this neat technical knowledge is enough "stuff" so that you can listen to anybody talk about anything to any level of detail the other speaker wants to go to, but you're not good for anything. (Generally, you also know enough about the subject to tell what is BS and what is correct, but the other guy always knows soemthing more than you do.)

Safety, quality concerns, "the devil in the details," trying to find, troubleshoot, anticipate, fix the systemic-level problems before they get worse, looking for trends before they can start a safety problem - that's what you really want in a nuke. (If I were to wax philisophical and order my ideal engineer.)

A good "nuke" should be looking at the whole thing, trying to apply the safety or critical systems-level thought that spans individual tasks. If soembody else is painting the forest, a nuke may be counting pine needles and trying to find out where the next pine borer infestation is going to break out. (But then you still have to go find a insect guy (can't spell etymologists) to fix the pine borer problem.)

We (nukes) can't see the forest for the trees... hell, .we're too busy looking for pine needles in the haystack. But at the same time, you're supposed to preparing for a forest fire, with a backup plan in case the fire fighters are busy, and their hose breaks, and their engine runs out of gas, ..... and design things so nobody can accidently hook up the fire hose to the gas tank.

-- Robert A. Cook, P.E. (cook.r@csaatl.com), October 21, 1998.

Robert,

Thank you for sharing of yourself with us yet again. Not only have you retained my respect, you have increased it greatly; not by any of your explanations (although they certainly lived up to expectations) but by revealing that you have earned the right to put the letters, "S.S." after your name.

-- Hardliner (searcher@internet.com), October 21, 1998.

Hardliner has it right. We increasingly live in a world of complex "black boxes" surrounded by ignorance. You have given us an insight into your black box. Some are more difficult to comprehend than others. SS I assume means superstar.

-- Richard Dale (rdale@figroup.co.uk), October 21, 1998.