ML20090L710
| ML20090L710 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 12/10/1975 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| 13859, NUDOCS 9102120552 | |
| Download: ML20090L710 (3) | |
Text
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NORTHERN STATES POWER COMPANY M I N N E A P o l.l e. M I N N E S O T A 88401 December 10, 1975 ea g
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Ziemann, Chicf Ope rat ing Reac tors liranch # 2
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V Division of Reactor Licensing
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g U.S. Nuclear Regulatory Conraission 4
Washington, DC 20555 e
Dear Mr. Ziemann:
MONTICELLO NUCLEAR GENEPATING PIANT Docket No. 50-263 License No. DPR-22 Status of Modifications Ileing Made to Mitigate the Consequences o f In te rio r F'. coding a t tit Monticello Nuclear Generating Plant in correspondence dated September 28, 1972, August 24, 1973, and September 10, 1973, Northern Ststes Power Company responded to an inquiry f rom the Commission to evaluate tio potential for interior flooding at the Monticello Nuclear Generating Plant.
The conclus-ions of this evaluation were that* no single pipe failure with re-sultant water flooding will prevent safe reactor shutdown or cause the loss of redundant engineered safety systems.
Two modifica-sC Q,'7 G
tiens were identified, however, which were desirable, to enhance engineered safety system redundancy.
These modifications were:
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Flood probes in the condenser hotwell area and in q' g g the circulating water pump bay with alarms in the
,O control room and automatic trip of circulating gi va p
water pumps on high 1cvel in either acca.
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Upgrading of the c 7ndensate transfer lines in
/y the Reactor 11uilding basement and HPCI Room to seismic category I equivalent.
These modifications were completed during the Autumn 1975 refueling outage with the exception of the automatic circulating water pump trip.
Ilecause of delays in the equipment procurement process, nec-essary material was not available to complete this portion of the 13859 9102120552 751210 PDR ADOCK 05000263 p
d NORTHERN OTATED POWER COMPANY l
Mr.
D.
1,. 7,lemann 2
Th?cember 10, 1975 planned modifications.
1,evel ala nns were installed in the con-denser hotwell area and in the circulating water pump bay and will annunciate in the Control Room in the event of flooding to pennit a Control Room Operator to manually trip the circulating water pumps.
The necessary material to complete work on the a:*nmatic trip feature is now available at the plant.
This portion of the modi-fication will be completed during the next scheduled plant out-age of seven days or longer duration.
In addition, a thorough inspection of all rubber expansion joints used in the circulat-ing water system was conducted during the Autumn 1975 refueling outage.
Very t ruly yours, L.
O.
Mayer, PE Manager, huclear Support Services int /ItN/ deb cc:
- 1. G. )*cppler G. Charnoff tipCA Attn:
J. W.
Fe nnan I
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. NRC DISTRIBU TION FOR PART 50 DOCKET MATERI AL
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CONTROL NO: / 3 G ', L FILE:
FROM: Nortnetn states Power Co DATE OF DOC DATE REC'D LT R TWX RPT OTHER Minneaputas, Mn L Q._Mayn ll-LR- />
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ENCLOSURES:
Ltr te (nert lors utu y-28-72, 8-24-/J,
/-10-/3........tusnasnsng into con:erning status of modifications being made to mitigate the con-sequences of interior flooding at tponticello....
PL ANT NAME: Monticello
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