ML19329A130
| ML19329A130 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 01/17/1977 |
| From: | Goller K Office of Nuclear Reactor Regulation |
| To: | Lear G, Schwencer A, Ziemann D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19329A126 | List: |
| References | |
| NUDOCS 7912300150 | |
| Download: ML19329A130 (3) | |
Text
UNITED STATES
. gf NUCLEAR REGULATORY COMMISSION dg g
3 WASHINGTON, D. C. 20656 g
,j_
January 17, 1977 g
MEMORAN00M FOR:
A. Schwencer, Chief, Operating Reactors Branch #1, D0R D. Ziemann, Chief, Operating Reactors Branch #2, D0R G. Lear, Chief, Operating Reactors Branch #3, D0R R. Reid, Chief, Operating Reactors Branch #4, D0R Karl R. Goller, Assistant Director for Operating Reactors, FP' ":
D0R
SUBJECT:
FLOODING OF TURBINE BUILDING Recently the NRC staff reviewed the turbine building flooding incident which occurred at Oconee Nuclear Station on October 10, 1976.
The attached enclosure is a draft DDR to DSS " feedback memorandum" which describes the details of this incident, including the interim corrective action which has been taken by the licensee.
The Oconee flooding incident occurred as a result of the inadvertent opening of'a main condenser isolation valve in the circulating water system while the condenser was open f,or maintenance. The fact that flooding of the turbine building continued 'until"the, valve could be repositioned raised concerns regarding the consequences of an unisolable break in the circulating water system piping inside the turbine building.
A preliminary review indicates that this potential problem may be unique to the Oconee Nuclear Station in that the elevation differential between the main condenser (775 feet MSL) and the source of circulating water (800 feet MSL) at Oconee provides a driving force for continued water flow into the turbine building should an unisolable piping break occur.
It should be noted that, if a facility's main condenser is located at an elevation higher than that of the source of circulating water, the adverse consequences of an unisolable break in the circulating water piping would be minimized.
Due to the significance of this concern, it is desirable to conduct ac e detailed investigation to detennine if the problem is unique to Oconu Therefore, ORPits should examine any available information on this
/ not.
generic technical issue for their assigned facilities (many licensees L
responded to this concern in late 1972 or early 1973) to detennine:
h hg If there has been any previous consideration of the potential a.
l consequences of a break in the circulating water system piping.
b.
Whether these considerations were limited to the failure of seals Nb and/or expansion bellows in the circulating water system or if pipe ruptures anywhere in the system, including u.iisolable NN locations, were considered.
i h
7912300 [
- s. 8T If the f acility's main condenser and/or any of the circulating water
-- - c.
P ping within the turbine building are located at an elevation lower i
u (P
/1 ll than that o' the source'of circulating water.
ORPMs should provide a written summary of their findings to John Guibert, D0R coordinator for this effort, by January 31, 1977.
r Karl R. Goller, Assistant Director for Operating Reactors Division of Operating Reactors i
Enclosure:
Draft Feedback Memorandum Regarding the Turbine Building Flooding Incident at Oconee Nuclear Station cc:
V. Stello D. Eisenhut W. Butler B. Buckley J. Reece ORPM's l
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