ML20039A723
| ML20039A723 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 05/31/1981 |
| From: | Broderick N, Ruvalcaba W, Wade W LAWRENCE LIVERMORE NATIONAL LABORATORY |
| To: | |
| Shared Package | |
| ML20039A718 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.E.4.2, TASK-TM NUDOCS 8112210204 | |
| Download: ML20039A723 (2) | |
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EGnG Entrcy Moccurcrncnto Crau3 SRO-278 San Ramon Operations May 1981 i
TECHNICAL EVALUATION OF THE RESPONSE TO -POS.lTION NO.5 OF ITEM H: E. 4.2 OF NUREG-0737 CONTAINMENT ISOLATION SETPOINT FOR THE VERMO NT.Y A N K EE NUCLEAR POWER PLANT (D OC K ET N O. 50-271 )
by W. O. Wade Approved for Puolication A/ / 4 ~.I... l..-
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- w. R. Ruvalcaca Department Manager-This document is UNCLASSIFIED Derivative Classifier: 3 4 [A d d Nicnolas4. drocericK
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Department Manager Work Performed fer Lawrence Livermore National Laboratory uncer U.S. Department of Energy Contract No. C E. ACOS.76 NVO 1183.
9112210204 811208 ADOCK05000g DR
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f INTRODUCTION AND BACKGROUND
- As a consequence of tne incident at TMI-2, implementation of a
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number of new requirements nas been recommended for operating reactors.
These r.ew requirements are descrioed in NUREG-0660, "NRC Action Plan Devel-oped as a Result of the TMI-2 Accident," May 1980.. and NUREG-0737, "Clari-fication of TMI Action Plan Requirements," November 1980.
Tne-NRC staff nas also requested. licensees to submit information sufficient to permit an independent evaluation of tneir response to tnese new requirements.
Inis report provides an e' valuation of the response to Action Plan Item II.E.4.2, position 5, by tne designeted, licensee.
DESIGN BASIS OR REVIEW CRITERIA Position 5 requires that tne containment pressure setpoint tnat initiates containment isolation for non-essential system containment vessel
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penetrations be at, or reduced to, "...tne minimum compatiole witn normal operating conditions."
TECHNICAL EVALUATION Response evaluation is based upon the values provided for tne following parameters:
(1)
The maximum observed or expected containment pressure during normal operation.
(2)
The loop error and observed drift in the pressure sensing instrumentation providing tne isolation signal (see note).
(3)
The containment isolation pressure setpoint.
NOTE: Tne clarification document (NOREG-0737) provided only
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the expected margin for instrument error and did not specify acceptable values for instrument drift or atmospheric cnanges contributing to tne total sensing loop error.
Additional staff guidance establisned a limit of 3.0 psi for an isolation setpoint margin over the normal containment pressure to account for total loop error.
In addition, for subatmospheric contain-ments, a 3.0 psi setpoint margin over atmospheric pressure is also considered acceptacle.
In consideration of tnese values, tne isolation pressure setpoint is to be as low as practical without increasing tne procacility of inadver-l tent activation of tne isolation signal.
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CONCLUSIONS Ine letter of December 15, 1980, submitted by Ve rmo_nt Yankee Nuclear Power Corporation, provided sufficient information to concluce that the containment isolation pressure. setpoint for Vermont Yankee Nuclear Power Plant. meets tne NUREG-0660/0737 requirements anc is witnin tne add-itional limiting guidelines provided by tne NRC staff.
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