What happens to Nukes on Aug. 22, 1999?

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If the NRC acts with the usual governmental decisiveness and does not shut down the nukes down on July 1, 1999, and if, as I understand, the GPS satellite is an intergal part of the operation of the power grid, what happens to the nukes if the grid fails at midnight, Aug. 21/22? Will we have 108 Chernobyls?

Claudia Doggett

-- Anonymous, December 15, 1998

Answers

This is the most important question now facing us: whether the nuclear power plants can be maintained in the face of a y2k crisis. It is my understanding, and please correct me if my information is wrong, that while the power plants have powerful standby diesel electric generators, they only have a 2 to 3 days worth of diesel fuel stored at the plants. The assumption is that either the crisis will be resolved within that timeline or that addtional diesel will be obtained in time. The core must be kept cool or a catastrophic meltdown can occur. Ironically enough, it's safer for the nuclear fuel rods to be kept in the reactor and not in the cooling ponds; account the core is enclosed in a containment building. If the nuclear power plants are not staffed and the reactors kept under control, the consequences stagger the mind. The radioactive elements released in a nuclear power plant meltdown actually are longerlived than from a nuclear device (which are really designed to maximize overpressure blast wave and heat).

-- Anonymous, December 15, 1998

Dr. Murray Jennex is the Y2K physical assets manager for a large nuclear utility. I asked him to join a discussion last week. Here is what he shared. He later shared a excerpt from this note in answering a specific question. This is his original complete post and the message I forarded to him. Best wishes, Leon Kappelman

Associate Professor, Business Computer Information Systems Associate Director, Center for Quality & Productivity College of Business Administration, University of North Texas Co-chair, SIM Year 2000 Working Group (http://www.year2000.unt.edu) Voice: 940-565-3110 Fax: 940-565-4935 Email: kapp@unt.edu Website: http://www.year2000.unt.edu/kappelma/ ==================================================================

------- Forwarded Message Follows ------- From: "Jennex, Murray" Subject: Nuclear power Date sent: Thu, 10 Dec 1998 15:11:36 -0800

Leon,

Nuclear plants have fewer critical digital control systems than modern conventional plants have. We've only been building modern conventional plants for the last several years, if nuclear plants have multiple failures I would suggest we would [have] many more other problems and the public may not even notice the nuclear plants (there will be no grid and it won't be due to the nukes)

Please forward to the appropriate listservers. (Note, I have 17 years nuclear engineering and operations experience, am a licensed mechanical engineer, and am the Y2K physical assets manager for a large nuclear utility) Power down as it is used and described below can mean a shutdown or a power runback. A runback is when you go from a high power level to a preset lower power level, usually 100% down to 75% or 55%. This is usually done due to steam demand or power system demand problems and is sensed at the turbine. At any rate, possible outcomes of Y2K are that nuclear plants are prepositioned at a lower power level or that problems cause a plant to trip or runback. Operating at a lower level is a possibility but not one that nuclear people recommend. Nuclear power plants can shut down quickly but they go up in power relatively slowly (about 5% per hour). Operating at a lower power level is proposed as a contingency in case conventional plants trip off, allowing nuclear plants to pick up the load. This won't happen because you can't load a plant quickly due to thermal and power flux considerations. On the other hand, nuclear plants can and do shutdown quickly in emergencies with no thermal effects. Equipment is designed with thermal transients in mind and can withstand many many thermal cycles. It is always preferable to shutdown slowly in a controlled manner because that transient does not count against the allowed number of thermal transients built into the plant's operating license, but any one emergency shutdown is not a big deal. I know of no US plants which are close to their thermal cycling limits if anyone is wondering so that is not an issue. Inspections are not necessary after a emergency shutdown either. In the US, any nuclear plant that has a trip must determine the cause and fix it prior to restart, that is the only constraint to restarting a nuclear plant. There is one exception and that is at the end of core life there is a Xenon peak transient that can prevent restart for several hours. This transient tends to hit peak about 8 hours after shutdown and is a problem for a couple of days. I do not know how many plants will be at the end of cycle when that would be a problem as they have various fuel cycles running from 1 to 2 years. Also, this is only a problem the last month or so of the cycle. As to statements that you can't run with known defects in safety equipment, that is true to a point. The actual equipment conditions allowed are specified in each plant's operating license. There are many cases where certain systems can be degraded or out of service with the plant at full power as long as backup systems are in effect. However, every US plant has a Y2K program. I guess the big question is, is a plant degraded if we know there is a piece of equipment that will need to be reset in order to eliminate a Y2K problem. The answer to that is no since we can have plans in place to handle that situation. The situation of unknown Y2K problems causing the nuclear plants to be shutdown before Y2K is not a likely event. Each plant has to have a program modeled on NEI 97-07. This document specifies a process for assessing and fixing Y2K problems. The NRC is currently assessing the programs of 12 nuclear plants and have yet to find a deficient program. This is the only thing that would cause the NRC to shutdown nuclear plants (finding deficient programs). NERC and the utility industry actually wants and needs the nuclear plants to be up and running at full power. NERC currently states that there is a reasonable chance that 25% of nuclear plants could trip due to Y2K. The nuclear industry through NEI actually do not consider this a reasonable possibility. I guess the final question is could a Y2K shutdown take out enough equipment to cause a major component or system to be damaged and take many months to fix. This is a unlikely possibility as US nuclear shutdown systems are not reliant upon digital technology. Critical valves are designed to operate with spring and pneumatic operators that would cause the valve to fail to its required emergency position should the plant trip and power be lost. No digital logic is used in this scheme. Critical control systems tend to be electro-mechanical and analog and are not Y2K impacted. The nuclear plants I am responsible for do not have any digital components in the key safety systems. Also, as a fail safe, all plants are designed to use natural circulation (i.e. no pumps or outside coolant prime movers) should a plant trip and the coolant pumps not work. Relief valves are provided should external cooling sources fail (this relieves pressure buildup caused by heat). Passive cooling water systems are available and are activated upon a loss of pressure (which is what would happen should a relief lift). Recovery from use of these systems would take several days or perhaps weeks but not four months (this is to clean up and dry out wiring, etc. and to test critical systems). I would rate the chance of a prolonged outage caused by Y2K to be very small. Hopefully this answers the many questions. thanks...murray

Murray E. Jennex Year 2000 Physical Assets Manager IT - Risk Management -------------

Year 2000 Links: http://www.cairns.net.au/~sharefin/Markets/Y2k.htm Alternative Links: http://www.cairns.net.au/~sharefin/Markets/Alternative.htm

-- Anonymous, December 16, 1998


Dick Mill's latest article on the Westergaard Year 2000 site provides perspective on the relative importance of GPS time data to the operation of the grid: http://www.y2ktimebomb.com/PP/RC/dm9849.htm

-- Anonymous, December 16, 1998

Dr. Jennex,

If the nuclear power plant monitoring system experiences a Y2K glitch and fails. Is the plant forced to shutdown because of operating procedures?

Is the plant allowed to keep running if the monitoring system is generating erroneous data or has failed completely?

Regards, --AJ

-- Anonymous, December 16, 1998


I would like to know how Dr. Jennex defines "prolonged outage". He mentions days or weeks of downtime possible, but "not four months". When talking about outage times, he also did not address any fix time for whatever caused the trip in the first place. Earlier in his response he said, "In the US, any nuclear plant that has a trip must determine the cause and fix it prior to restart", but then he did not factor this into the possible downtime. What if the cause of the trip is outside the plant itself and not within its control? (As in interconnections with non-nuclear generation stations, grid problems causing a station trip, or telecommunications problems causing the same.)

It's very heartening to have confirmation that critical nuclear safety systems are not dependent on computers. However, as A. J. questions, if a monitoring system has problems, or there is an outside grid/telecom problem, then the net result is still NO generation for "days or weeks". To me, it appears that Dr. Jennex is saying that we'll either have safe nuclear generation, or we'll have safe shutdowns and safe nuclear non-generation. One problem down. Keeping the lights on still in question.

-- Anonymous, December 16, 1998



How about event logging? Are you going to have event logging or not? Might be difficult to do a fix and restart without event logging.

-- Anonymous, December 20, 1998

any help here?

a long thread with some problematic unanawered questions and issues...

anyone up to addressing some of them - - -

or even just commenting on??

-- Anonymous, April 05, 1999


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