ML19247A896
| ML19247A896 | |
| Person / Time | |
|---|---|
| Site: | North Anna, 05000434, 05000435  |
| Issue date: | 06/21/1979 |
| From: | Lainas G Office of Nuclear Reactor Regulation |
| To: | Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| NUDOCS 7908030306 | |
| Download: ML19247A896 (2) | |
Text
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.,.C W ASHINGTON, D. C. 20555 JUN 211979 MEMORANDUM FOR:
E... Jordan, Assistant Director for Technical Program, Division of Reactor Operations Inspections R. H. Vollmer, Assistant Director for Systems andh[
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Projects, Division of Operating Reactors FROM:
G. Lainas, Chief, Plant Systems Branch, Division of Operating Reactors
SUBJECT:
POTENTIAL ELECTRICAL BUS OVERLOADS AT NORTH ANNA AND SURRY POWER PLANTS
REFERENCE:
E. L. Jordan's memorandum to R. Vollmer dated June 4,1979 on the above subject The reference describes two different potential electrical system overload problems - one at North Anna and the other at Surry Power Plant. The problems reported and proposed corrective actions by the licensee are as follows:
1.
North Anna Plant - Preliminary notification PNII/79-45, identifies undersized transfer busses and their associated bus supply breaker and cabling from the station reserve transformer serfing both units.
Certain conditions of plant operation, such as one unit in startuo and the other tripped from full power operation, would impose a load higher than what the transfer bus is designed to handle. This condition will cause over heating and possible failure of the transfer bus and its associated components.
The licensee has subsequently submitted a design revision to correct this problem and the submittal is currently under review by Power Systems Branch, DSS.
2.
Surry Unit - Two load centers, one each on the two trains of the Class lE power systs.s in Unit 1, were found to be of insufficient capacity to supply power to their connected loads. The licensee nas recently submitted a revised design (increased capacity) to address this problem and the submittal is presently being reviewed oy Plant Systems Branch, DOR f
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JUN 211979 f)$ C N During a meeting on May 3,1979 with the licensee (Surry 1) and the architect-engineer (Stone and Webster), we enquired about other S&W designed nuclear power plants which could have similar potential electrical system overload problems.
S&W informed us that none existed, Further, we will be reviewing licensee's submittals on the degraded grid voltage as part of our proposed review of the expanded Generic Task B-23, Degraded Grid Voltage.
Any similar potential overload problems, should be identified and addressed during this review.
VA G. Lainas, Chief Plant Systems Branch Division of Operating React rs
Contact:
I. Ahmed, X28077 cc:
D. Eisenhut R. Vollmer F. Rosa E. Reeves D. Neighbors A. Dromerick G. Lainas D. Tondi V. Thomas R. C. Lewis, RII F. Cantrel, RII M. Chiramal S. Rhow I. Ahmed bb h(b