ML20237K171
| ML20237K171 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 08/24/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20237K169 | List: |
| References | |
| TAC-65248, TAC-65249, NUDOCS 8708270080 | |
| Download: ML20237K171 (3) | |
Text
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$* ** GU
[j fg UNITED sVATES
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g NUCLEAR REGULATORY COMMISSION g -
-E WASHINGTON, D. C. 20555
\\,. + *#j su SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIO_N SUPPORTING AMENDMENTS NOS. 146 AND 82 TO FACILITY OPERATING LICENSES DPR-57 AND NPF-5 GEORGIA POWER COMPANY OGLETHORPE POWER CORPORATION MUNICIPAL LLLLIRIC AUTH0kllY OF GEORGIA CITY OF DALTON, GLORGIA EDWIN 1. HATCH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-321 AND 50-366 l
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INTRODUCTION sy submittal dated March 27,1987 (Reference 1), Georgia Power Company (the 4
licensee) requested amendments to the Technical specifications (TS) for the I
Edwin I. Hatch Nuclear Plant, Units 1 and 2.
The requested changes would l
revise the TS alarm setpoint for the Unit 2 Core Spray sparger differential l
pressure, and would add this setpoint to the Unit 1 TS, which presently has l
no setpoint specified.
EVALUATION Instrumentation is provided in both Unit I and Unit 2 to measure the differential pressure across the reactor shroud.
Its purpose is to detect a gross failure in the core spray sparger piping, which would be indicated by a change in the differential pressure, and alert the control room operator by actuating a control room annunciator. The instrumentation provides no trip function.
The reference differential pressure setting for the Unit 1 instrumentation was never formally specified in the TS. The existing, Unit 1 TS, Table 3.2-6, states "to be detemined during startup testing" in the column showing setpoints for instrumentation.
In fact, Unit I has been operating with a differential pressure instrument setting about 0.75 psid greater (less negative) than the normal differential pressure. The Unit 2 TS state that the setpoint is 10.5 psid greater than the nonnal indicated differential pressure.
In practice, there is no " normal" differential pressure, since it varies with variations in reactor power and reactor coolant floc /. As a result of these fluctuations in the indicated differential pressure, the licensee has found that the small margin of 110.5 psid allowed by the TS for Unit 2 for the alarm setpoint is insufficient to prevent the occurrence of nuisance alarms.
8708270080 870824 DR ADOCK 050 1
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1 l The licensee is now proposin
'psid greater (less negative)g to revise the instrument setpoint to "6 3.1 than the normal indicateda P at rated core power and flow." T:.e proposed new setpoint is based upon Hatch specific recommendations made by General Electric in Service Information Letter (SIL) No. 300.
The SIL recomends that the differential pressure setpoint be set based upon that differential pressure associated with rated power and flow, since the instrumentation was designed to be effective only when the core flow is between 90 percent and 100 percent of rated.
The value of 3.1 psid is based upon a conservative analytical limit of 3.6 psid, and was selected using the
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methodology of Regulatory Guide 1.105.
The analytical limit of 3.6 psid is still well below the change in differential pressure that would occur should there be a break in the core spray sparger piping while operating near rated power and flow.
In addition to entering the new setpoint in both the Hatch Unit I and Unit 2 TS, a footnote would be added-to Table 3.2-6 of the Unit 1 TS to point out that the instrumentation provides an alarm only, and that if the instrumentation is inoperable, the actual differential pressure must be verified to be within limits at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or i.he associated core spray loop must be declared inoperable.
l The result of the proposed changes would be to (1) revise the setpoint for Unit 2; (2) add this setpoint for Unit 1, which presently has no setpoint specified; (3) alert the operators that the instrumentation provides only an i
alann function; and (4) instruct the operators that, in the event the l
instrumentation becomes inoperable, the actual differential pressure must be j
verified to be within limits every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or the associated core spray loop j
must be declared inoperable.
Since the differential core spray sparger instrumentation provides an alarm j
only, and since the proposed revised setpoint for Unit 2 and the added setpoint i
for Unit I still provide margin to the change in differential pressure that I
would occur in the event of a piping break, we find these changes acceptable.
The resulting TS setpoints and action statements will provide for consistency between the two sets of Technical Specifications.
ENVIRONMENTAL CONSIDERATIONS These amendments involve a change in use of facility components located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requi rements. The staff has determined that the amendments involve no signif-l icant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there should be no signif-icant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR $51.22(c)(9).
Pursuant to 10 CFR 651.22(b), no environmental impact statement or environmental assessment need be prepared in cm.nection with the issuance of the amendments.
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- CONCLUSION
' The Commission made a proposed determination that the amendments involve no significant hazards consideration which was published in the Federal Register (52-FR 20800) on June 3, 1987, and consulted with the state of Georgia.
No public comments were received, and the state of Georgia did not have any-cnoments.
The staff has. concluded, based on the considerations discussed above, that:
(1) there is-reasonable Lssurance that the health and safety of the.public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendments will not-be inimical to the common defense and security or.to the health and safety of the public.
Principal Contributor:
L.-Crocker Dated: August 24, 1987 i
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