ML19340E073
| ML19340E073 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 12/22/1980 |
| From: | Randazza J Maine Yankee |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| TASK-2.E.4.2, TASK-TM WMY-80-164, NUDOCS 8101060320 | |
| Download: ML19340E073 (2) | |
Text
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,% MAME '=a?i9AllHEEj ATG:it!C POL'HR COMPARS
- auaugraja?7lgosls (2cn 623-3521
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December 22, 1960
'AMY-80-16a B. 3.2.1 k
Urited States Nuclear Reculatory Commission VasSington, D. C.
20555 Attention:
Office of ?!uclear Reactor Reculation Robert A. Clark, Branch Chief Ocerating Reactor Branch I!o. 3
References:
(a)
Licerse Fo. DPR-36 (Docket t'o. 50-309)
(b)
USNRC Letter, D. G. Eisengut to All Licensees of Operating Plants, dated October 31, 1980.
(c) t!UREG-0737
Subject:
Contairment Pressure Setpoint.
Deer Sir:
Reference (b) transmitted reference (c) which includes all TMI-2 related items approved for imolementation by the Cormission as of October 31, 1980.
Item II.E.4.2 reference (b) required, inter alia, "The containment setpoint oressure that initiates containrent isolation for noressential penetrations must be reduced to the minimum compatible with normal operating conditions."
The clarification of this requirement states:
"The containment pressure history during normal operation should be used as a basis for arriving at an approoriate ninicun pressure setpoint for initiating containcent isolation.
The pressure setpoint selected should i
l be far enough above the maximum observed (or expected) pressure inside l
containment during normal operation 50 that inadvertent containment isolation does not occur during normal operation from instrument drift or fluctuations due to the accuracy of the pressure sensor.
A maroin l
of 1 psi above the maximum expected contairment pressure should be l
adequate to account for instrument error. Any pronosed values greater than 1 psi will require detailed justification."
l
!daine Yankee has reviewed the containment pressure history, the local l
baroretric pressure history and the calibration data for the containment isolation pressure sensors to evaluate the optimum setpoint to insure containment isolation prior to reachire 5 psig as required by the Operating License while preventing i
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4 MAINE YANKEE ATOMIC POWER COMPANY
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spurious trips due to instrument drift, fluctuation in the accuracy of the sensor or fluctuations in local barometric pressure.
Results of this evaluation are as follows:
1
- 1. Maximum observed containment pressure (Pc) = 34.3 in Hg. (1/1/78 to 12/7/80).
2.
Minimum observed atmospheric pressure (Patm.) 28.4 in Hg. (1/1/78 to 12/7/80).
l 3.
Typical atmospheric pressure (Patm.) = 29.9 in. Hg.
i 4.
Maximum expected atmospheric pressure = 31.3 in.Hg.
i 5.
The maximum A P expected between containment Pressure and atomospheric pressure is 3.0 psi.
t 6.
Maine Yankee containment isolation trip setpoint is set to actuate between 4.25 and 4.75 psi.
This setpoint is considered adequate to insure actuation by 5 PSIG and to prevent actuation due to local barometric pressure changes due to i
severe storms and/or instrument drift.
No changes to this setpoint are planned.
I We trust the information herein is adequate, however, if further clarification is necessary, do not hesitate to contact us.
Very t'ruly yours, MAINE YANKEE ATOMIC POWER COMPANY hb YM Jy i
tohn B. Randazza Vice President, Operations l
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