ML19332G080
| ML19332G080 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/11/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19332G074 | List: |
| References | |
| NUDOCS 8912200134 | |
| Download: ML19332G080 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 1
RELATED TO AMENDMENT NO. 41 TO FACILITY OPERATING LICENSE NO. DPR-21 NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION. UNIT NO. 1 DOCKET-NO. 50-245
' INTRODUCTION l
By [[letter::B12535, Application for Amend to License DPR-21,revising Tech Specs to Change Reactor Protection Sys Trip Level Settings.Amend Will Delete Electrical Power Ref & Change Both Scram Bypass Setpoints & APRM Flux Scram Trip Setting.Fee Paid|letter dated August 17,1987]], Northeast Nuclear Energy Company (the licensee) submitted a request to amend the Operating License, DPR-21, for Millstone Nuclear Power Station, Unit No. 1.
Specifically, the request would change the Technical Specifications for the Reactor Protection System (RPS) by (1) changing the turbine stop valve closure scram bypass from less than 45% of-
. turbine steam flow, es measured by the turbine first stage pressure, to 50% of reactorthermalpower;(2)changetheturbinecontrolvalvefastclosurescram bypass from a generator output ef less than 307 MWe to 50% of reactor thermal power; and (3) charige the Average Power Radiation Monitor (APRM) flux. scram trip setting from an' initial generator power greater than 307 MWe to 50% of reactor thermal power.
EVALUATION In its [[letter::B12535, Application for Amend to License DPR-21,revising Tech Specs to Change Reactor Protection Sys Trip Level Settings.Amend Will Delete Electrical Power Ref & Change Both Scram Bypass Setpoints & APRM Flux Scram Trip Setting.Fee Paid|August 17, 1987, letter]] the licensee stated that the scram bypass setpoints were being changed because opening the bypass valves or valving out p
the high-pressure feedwater heaters during end-of-cycle plant coastdown alters the usual direct relationship between reactor power, turbine first stage l
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pressure and generator output.
In addition, spurious scrams which occur more L
frequent 1ly at lower power can be avoided by raising the setpoints. Unlike the bypass setpoints, the change in the APRM flux scram trip setting does not constitute a change in the setpoint, but is being made to add to the clarification and consistency of the TS, in that the units of measurement will be the same.as the other scram trip settings.
Because of the proposed change in setpoints to 50% of rated reactor thermal ower, the licensee re-evaluated the bounding transients for Millstone 1 p[ General Electric ~ Analysis MDE-276-1285, " Millstone Nuclear Power Station Unit L
L No.1 Scram Bypass Setpoint Evaluation," dated December 1985). The licensee's evaluation supported the proposed change to the scram bypass setpoints in that L
the consequer.ces of design basis accidents were determined to be less severe L
than those in the current reload analysis and that no safety limits would be L
challenged.
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i' The staff has reviewed the licensee's request and the evaluation and concludes
~that impact of the changes are bounded by and do not affect the current design accident analyses, do not introduce any new failure modes, and do not affect any protective barriers or safety limits.
In addition the change to the APRM flux scram TS is an acceptable clarification. Therefore, the staff finds the
-11censee's proposed changes to the TS to be acceptable.
ENVIRONt1 ENTAL CONSIDERATION Pursuant to 10 CFR 51.21, 51.32, and 51.35, an environmental assessment and finding of no significant impact have been prepared and published in the Federal Register on December 6, 1989 (54 FR 50460)..-Accordingly, based upon the environmentel assessment, we have determined that the issuance of the amendment will not have a significant effect on the quality of.the human environment.
C0t:CLUS10fl We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance tnat the health and safety of the public will not be endergetedbyoperationintheproposedmanner,and(2)suchactivitieswill be conducted in compliance with the Comission's regulations, and (3) the issuar.ce of the amendment will r.ct be inimical to the comon defense and security or to the health and safety o' the public.
Dated: December 11, 1989
-Principal Contributor:
M. Boyle 1
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