ML19273C200
| ML19273C200 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 11/13/1979 |
| From: | Linder F DAIRYLAND POWER COOPERATIVE |
| To: | |
| References | |
| LAC-6643, NUDOCS 7911210470 | |
| Download: ML19273C200 (2) | |
Text
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D. tilt YL.t.YD 1*O WE18 C00I*ER.t TIYE fa 6one, 0)keann
$4601 November 13, 1979 In reply, please refer to LAC-6643 COCFET '0.
50-4C9 Mr. James G.
Keppler Regional Director U.
S.
Nuclear Regulatory Commission Directorate of Regulatory Operations Region III 799 Recsevelt Read Glen Ellyn, Illinois 60137
SUBJECT:
DAIRYLAND PCWER CCOPERATIVE LA CROSSE BCILING WATER REACTCR (LACEWP}
PROVISIONAL CPERATING LICENSE NO. DPR-45 REPORTABLE OCCURRENCE NO. 79-17
References:
(1)
LACBWR Technical Specifications, Secticn 3.9.2.a.(2)
(2)
LACBWR Technical Specifications, Section 4.2.2.3
Dear Mr. Keppler:
In acccrdance with Reference (1), this is to infern ycu cf :Per-ation during which a limiting conditier was exceeded.
On November 9, 1979, an unexpected reducticn in freedom of ecvement of the turbine governcr initial pressure regulator centributed to primary system pressure and flow variations which resulted in a reactor scram.
Following the scram, the cooldown rate of the reactor vessel 0F/hr. during a 22-minute period where the initial averaged 423 temperature was 560 0F and the later temperature was 4t5 CF.
LACBWR Technical Specifications (Reference 2) limits the reacter vessel cooldown rate to 150 0F/hr. during shutdown operations of the reactor.
Following a similar experience in May 1970 where the reactor vessel cooldown race exceeded Technical Specification limits, a detailed engi.eering analysis was performed
(" Reactor Vessel Stresses, Fuel Temperature and Cladding Stress Calculations Following Main Steam Bypass Valve Malfunction" - United Nuclear Corporation report SS-588 dated June 8, 1970).
The cooldown rate analyzed in this 7 011210 'F 7 #
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M 1
D fl D
l O
A J a Ugg, ((
Mr. James G.
Keppler LAC-6E43 Regional Directcr "ovember 12, 19~9 U.
S. Muclear Regulatory Commission report was greater than the cocidewn rate recent1'. experienced.
The report cencluded that the vessel stresses during the 1970 incident were well within the allcwable stress intensities cf Section I!I, ASMC Boiler and Pressure Vessel Cede, Nuclear Vessels.
Prarpt notif;caticn of this event was 7,ade to "r.
ScPcules cf Regicn III, U.
S.
- uclear Regulatory Catnissicn, at 1700 en Ncvember 9, 1979.
If there are a r '; questians 2:.cornina this rer rt, :' lease cc. tact us.
ery truly,* ur9, wi..r m.1 w r 3 r. y \\
m.
c c. u
..,..... r.
.a w
Frank Linder, Janeral "r.s~er FL:LSG:af cc:
Director, r#fice
'f 2*anagement Infernati:-
and Pr gram Control U.
S.
Nuclear Regulatory Ccm. mission Washington, D.
C.
20555
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