ML20210L660
| ML20210L660 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 08/05/1999 |
| From: | Tam P NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| TAC-MA5205, TAC-MA5206, TAC-MA5422, TAC-MA5423, NUDOCS 9908090194 | |
| Download: ML20210L660 (2) | |
Text
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p-4 UNITED STATES g
,j NUCLEAR REGULATORY COMMISSION
't WASHINGTON, D.C. 20555-0001
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August 5,1999 MEMORANDUM FOR:
Docket File FROM:
Peter S. Tam, Senior Project Manager, Section 1 Project Directorate ll Division of Licensing Project Management g
Office of Nuclear Reactor Regulation
SUBJECT:
CATAWBA AND MCGUIRE NUCLEAR STATIONS --
DOCUMENT ON MIXED OXIDE FUEL RECEIVED FROM TOM CLEMENTS OF THE NUCLEAR CONTROL INSTITUTE (TAC MA5205, MA5206, MA5422 AND MA5423)
The attached single-page document was given to G. Belisle of Region 11 by Tom Clements of the Nuclear ControlInstitute. By copy of this memorandum NRC personnellisted below are provided a copy of Clements' document for their information and consideration.
Docket Numbers 50-413,50-414, 50-369,50-370 Distribution PUBLIC R. Emch J. Wilson U.Shoop M. Chatterton H. Astwood F. Rinaldi
'N N. Kalyanam L
l 000067 L
9900090194 990005 l
DR ADOCK 05000369 l
i
.,,.a Duke Power, MOX and Ice Condensers July 20,1999 The Catawba and McGuire plants have containment structures that are significantly less robust than most other U.S. pressurized-water reactors. The Chairman of the NRC Advisory Committee on Reactor Safeguards (ACRS) recently referred to them as " weak containments " These plants depend on ice c*-r systems - annular chambers enania% tiers of baskets carrying millions of pounds ofice - to condense steam i; sed during loss-of-coolant accidents (LOCAs) in order to relieve the pressure on the contamment walls. Ice ca '=:r systems cannot mitigate other accident conditions that could challenge the containment, such as hydrogen explosions, which require additional equipment to control.
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In order for the ice h=rs to work properly, steam produced during a LOCA must be able to flow without resistance through the ice chambers. This requires that the main and intermediate bay dov s i
I always be able to open freely and that steam flow passageways remam unobstructed. In the past, ice condenser functioning has been challenged by sticking of the bay doors due to ice buildup or warping of the floor underneath the doors. Other serious issues include the accumulaton of debris in the ice and ice baskets, which could clog reactor drains and affect the flow of recirculatmg cooling water fnun the l
contamment sump. This debris includes trash which falls into ice baskets during maintenance and broken I
ice basket screws resulting from manufacturing flaws.
NRC's July 12 notice of the Catawba enforcement conference cites these problems and others. In fact, the similarities between the problems cited at Catawba and those experienced by another ice cc- '=
plant, D.C. Cook, are stnking The two D.C. Cook units have been off line since SeyL..Wi 1997, and restart is not planned before next year. The degraded condition of the ice enah-r system at D.C. Cook
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was one of the primary issues that led to the extended shutdown Ultunately, D.C. Cook w r e4 had to melt the ice in both units and undertake a complete rebuilding of the ice cer4erser system.
As the Department of Energy (DOE), via a contract to Duke Cogema Stone and Webster (DCS), is
)
considering use ofplutonium fuel (mixed uranium-plutonium oxide, MOX) made from " surplus" weapons-grade plutonium in the Catawba and McGuire reactors, the queston of operability ofice ec. hrs in the event of a severe accident becomes even more critical. Because the consequencee. of a severe, loss-of-contamment accident can be substantially greater for MOX cores than for low-enriched uranium (LEU) cores (as a result of the greater inventory of plutonium and minor actinides), the potential
~ inoperability of the ice condenser systems at Catawba and McGuire must be considered an even more serious safety issue when MOX is involved. (1) The Nuclear Control Institute, which is concerned about the safety and non-proliferation impacts of the DOE's weapons-grade plutonium " disposition" program, will remain vigilant in respect to the problems with ice condensers at Duke Power reactors and calls on the NRC to aggressively and comprehensively address this problem.
Tom Clements Executive Director Nuclear ControlInstitute 1000 Connecticut Ave, NW Suite 804 i
Waearn, DC 20036 tel. 202-822-8444, fax 202-452-0892
- clements@nci.org (1)1he cummary of a report on severe accident consequences using MOX, by Dr. Ed Lyman, NCI Scientific Director, can be found on the NCI web site at www.nci.org/moxsum.htm.