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[Fair Use: For Educational/Research Purposes Only]

Nuclear Plants: Post-Y2K Stress

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By Brian Krebs, Newsbytes - December 27, 1999

The world's 430 operating nuclear power plants in 34 countries should operate normally during the coming millennium date rollover, but performance problems could pop up in the weeks immediately following the New Year, according to a report issued today by the International Y2K Cooperation Center (IY2KCC).

"Unless Y2K work continues in plants where resources have been limited, Y2K-produced errors in operational management and monitoring systems will degrade overall plant performance in the weeks following the date change," said IY2KCC director Bruce W. McConnell. "Over time, such a degradation in performance would reduce the margins of safety and efficiency in these plants."

The report added that while many advanced nuclear plants employ digital systems that control plant operations and systems that initiate a reactor shutdown, the majority of digital systems are used in non-critical functions, such as monitoring fuel usage and demand load, and processing work orders.

At the same time, however, the report stressed the dependence of nuclear power plants on the normal performance of "external infrastructures," including the electric power grid, telecommunications, water and fuel deliveries, declaring that "failures in these systems can require plants to modify, cut back or discontinue operations."

To guard against the possibility of a temporary disruption in electric power grids, many nations - specifically those in the former Soviet Union states, India and Eastern Europe - will stockpile at least three weeks of diesel fuel to power the reactor cooling systems after a shutdown.

Given popular awareness of the 1986 Chernobyl disaster in Ukraine, specific attention was to Russia's nuclear power plants, most of which reportedly operate under a modified mixture of former Soviet and western technology.

"Fortunately, generation units in these plants use older control systems, with very few date-sensitive components," the report said. "Date-sensitive systems in these plants do not trigger automatic actions that would affect safety."

Year 2000 experts will be watching Russia's nuclear power plants for one other reason: They are the closest to the Greenwich mean time zone, and thus the world's first reactors to encounter the date rollover.

The IY2KCC's report also sought to address the popular belief that the best remedy for reducing the risk of nuclear disaster over the New Year weekend might be simply to shut down the reactors deemed most vulnerable to a the millennium bug. But, the report argued, doing so could create more problems than it seeks to solve.

"Shutdowns create their own risks. In addition, we note that keeping plants online increases the stability of the electrical distribution grid," the report said. "Because of the extensive Y2K work that has been done and the increased staffing and monitoring of nuclear power plant operations over the date change period, we do not believe there is a net safety benefit to a general shutdown of nuclear power plants during the period."

The IY2KCC on Monday released a report on the Year 2000 preparedness of 190 countries that participated in its survey. The study found that most nations should expect a multitude of inconvenient but non-life-threatening Year 2000-related problems over the New Year's weekend and for a short time thereafter.

Starting Dec. 29, 190 countries will provide updates to an Internet-based reporting system called the Global Status Watch (GSW), where national Year 2000 coordinators from each national government will input information from eight sectors in "real-time." The Website, accessible to the general public, will rate each sector based on that country's level of capacity: Green for all systems go, yellow to indicate a reduced capacity and red for serious problems.

The IY2KCC has prepared back up phone and fax systems of reporting, in case the very problem a given country is supposed to be monitoring and reporting affects their ability to do so.

In the event that a country experiences problems it cannot locally correct, "regional sector networks will enable the sharing of common problems and solution approaches," the report said.

In a joint effort between the Nuclear Energy Agency of the Organization for Economic Cooperation and Development and the US Nuclear Regulatory Commission, officials have developed the Y2K Early Warning System (YEWS). YEWS will allow nuclear regulators to share information on the status of nuclear facilities over the New Year's weekend. Thus far, only 33 countries have joined the YEWS initiative.

The International Y2K Cooperation Center, was established in February 1999 under the auspices of the United Nations, with funding from The World Bank.

Data for The International Y2K Cooperation Center can be viewed starting Dec. 29, 1999, at:

http://www.iy2kcc.org

The Y2K Early Warning System is at:

http://www.nrc.gov/IP/Y2K/yewsfaq.htm

Reported by Newbytes.com

URL: http://currents.net/newstoday/99/12/27/news15.html

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Are they insane ?

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-- snooze button (alarmclock_2000@yahoo.com), December 27, 1999

Answers

Yes sir, this sure gives me a "warm and fuzzy" feeling. Maybe it's just me, but my take is that no one knows what the hell these Nuclear Plants will do under the circumstances. I get that Titanic feeling, there's the ice berg, we've hit it, now what?

In the name of all the gods, how can these people play around with this, basing their actions on assumptions of what if, maybe, could be, I'm not sure but, then there's always the chance that...

Millions of peoples lives may depend on their maybe actions. Mind boggling to me.

Well, one thing, if there is a lot of radiation we won't have to worry about lighting. All we'll need do is hold a light bulb in our hand, and it will glow, right?

-- Richard (Astral-Acrs@webtv.net), December 27, 1999.

Stock up on electrolytes, like Gatorade. Drinking quantities of this will increase the wattage output of held lightbulbs by 20-40%. ;-)

-- Ford Prefect (bring@your.towel), December 27, 1999.

Does any one know how long it takes to shut down a nuclear station safely? It's nice of them to monitor problems, but I'd feel much better if the power station twenty miles from me could be shut down rather than run the risk of unforeseen failure.

Heck, we won't need electricity for light if the nukes go down...WE"LL BE GLOWING!

-- TM (mercier7@pdnt.com), December 27, 1999.

Scram takes <1 second to initiate, full shutdown is immediate (1/2 second later.)

Planned shutdowns take about 2-4 minutes (depends on the design) to get the rods all the way down, but the reactor itself is sub-critical as soon as the rods begin moving down in the first seconds after the switch is turned.

Once the reactor is shutdown, cooldown can begin - I've done cooldown from regular operation to room temperature in 12 hours, usually you prefer to take 24-30 hours. My brother's plant averages 36-42 hours from planned shutdown to "no pressure, room temperature, core cover removed" (for routine refuelings).

Decayheat continues to be generated after shutdown - but at greatly reduced rates: 0.05% (.0005 of original power level) a few hours after shutdown is typical. Keeping a reactor cool is easy, with or without off-site power. The fuel in the spent fuel pools is equally easy to keep cool - just keep the water refilled is one technique. Emergency and backup generators and backup pumps and backup heat exchangers are sized to do the job.

-- Robert A Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 27, 1999.

Robert, you sound informed about this stuff. I once read that it takes 9 MONTHS to completely cool down a reactor. Is this true? I am within 10-15 miles of 2 reactors and often wonder what our chances are, though I have heard from good sources that the plant is completely compliant and ready for y2k. (no, not from koskinen or clinton, but from someone who was called in to work on the system)

-- cin (cinlooo@aol.com), December 27, 1999.

Typical nuclear plant can be completely cooled in less than 42 hours easily. After that time, small pumps keep moving small amounts of water around to keep temperaatures even and at room temperature. Almost all heat is gone after a week, and only neglible amounts remain after a month.

The "9-month cooldown" is an old wives tale that has no basis in practical measurement: the heat given off after a reaction is shutdown continues literally for years - but after a few weeks at such a low rate that the energy used in the pumps to move the water around is greater than the energy coming from the reactor. Thus, after about 4 weeks - if you turn the pumps "on" you heat up the water, if you leave them off and let natural conduction remove the decay heat - the plant keeps cooling down.

Another illustration: In summer time in the south, after a few months of shutdown time - the heat from the sun on the outside of the containment can be greater than that from the reactor inside.

To answer your question: yes - there is decay heat. No - it isn't very much and can be easily managed - with or without outside power.

Familiar with nukes? Yes - I've studied 'em, designed 'em, run 'em, analyzed 'em, built 'em and rebuilt 'em (Navy and commercial), refueled 'em, and refueled 'em. Been inside 'em, under 'em, over 'em, and (literally) through the middle of 'em tracing equipment, piping, cables, and sensors. Paid for 'em (long term budget estimating), set up long-tern and short term maintenance schedules for 'em, and did design and QA reviews for 'em. My BS degree is in Nuclear Engineering (covers nuclear physics, nuclear reaction mathematics and dynamic analysis, radiation health physics, reactor safety analysis, bunches of mechanical engineering, bunch of courses in civil engineering, lots of thermodynamics & heat transfer, structural analysis and structural/material design, electrical engineering, electrical control theory, electric power distribution, programming, and operational analysis theory. Navy nuclear power school and prototype repeated all these - then had ten years in various shipyard(s) actually building and re-testing the things.

My masters is Industrial Engineering - Quality Assurance/Quality Improvement (covers fields like business management, industrial and statistical measurement, process improvement, industrial distribution, software QA, software testing, financial management, etc.) Last ten years I've been doing software QA and testing for 3D CAD systems and databases. Most of these projects were nuclear plants worldwide, several were chemical and oil refineries, pulp and paper, Naval and commercial ships, and civil (power distribution, steam and electrical distribution systems - like for Manhatten Island for Con Ed.)

My dad designed the concrete and cooling towers and buildings for many nuclear plants in the sixties and seventies; my brother operated, repaired, trained the operators for them and is himself a qualified shift supervisor at one. So I've had many years of exposure to their systems.....taught me a lot - except how to type.

-- Robert A Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 27, 1999.