ML20137E938
| ML20137E938 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 01/09/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20137E904 | List: |
| References | |
| TAC-57643, NUDOCS 8601170356 | |
| Download: ML20137E938 (3) | |
Text
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gi ucog4 UNITED STATES
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NUCLEAR REGULATORY COMMISSION y
E WASHINGTON. D. C. 20655 g.
,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.60 TO FACILITY OPERATING LICENSE
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NO. NPF-5 GEORGIA POWER COMPANY OGLETHORPE POWER CORPORATION M"NICIPAL ELECTRIC AUTHORITY OF GEORGIA CITY OF DALTON, GEORGIA EDWIN I. HATCH NUCLEAR PLANT, UNIT NO. 2 DOCKET NO. 50-366
1.0 INTRODUCTION
During scheduled surveillance testing, four breakers were discovered i
which needed trip setpoints set at values higher than those currently specified in Technical Specification (TS) Table 3.8.2.6-1 in order for their associated circuits to function properly.
TS Table 3.8.2.6-1.
lists trip setpoints (in amperes) for circuit breakers which provide overcurrent protection for electrical penetrations through the primary containment.
By letter dated May 9, 1985, Georgia Power Company (GPC or the licensee) requested an emergency change to Edwin I. Hatch Nuclear Plant, Unit No. 2, TS 3.8.2.6 dealing with these setpoints.
The licensee requested approval of either of two separate proposed revisions to the TSs.
The licensee's preferred revision would remove all setpoints from Table 3.8.2.6-1, " Primary Containment Penetration Conductor Overcurrent Protective Devices." The alternate revision would modify the setpoints of four specific breakers serving the drywell cooling unit and the drywell cooling return air fans. Two additional changes of an administrative nature were requested.
These changes are common to either proposed revision. One administrative change corrects a typographical error in the parts listing for a component.
The other administrative change revises motor control center frame identifications for two breakers for circuits which have been moved.
According to the licensee, these administrative changes would not affect unit operation.
but are necessary to maintain the technical accuracy of the table.
During the review, questions were raised concerning the surveillance requirements of TS 4.8.2.6.1.a.2.
We reviewed the May 9, 1985, submittal on an emergency basis.
Removal of all setpoints from Table 3.8.2.6-1 was not evaluated at that time, as this did not appear appropriate in the context of an Emergency TS review.
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. Additionally, two changes of an administrative nature, as proposed by the licensee, were not addressed. We approved the proposed alternate revision to the TSs on May 10, 1985 (oral authorization) and issued Amendment No. 46 to the Unit 2 license incorporating this revision on May 14, 1985.
In our letter transmitting this amendment, we stated;that the other_ areas of change to the TSs requested in the licensee's May 9, 1985,-letter should be addressed in separate NRC actions.
By letter dated August 30, 1985, the licensee supplemented the information submitted in its May 9, 1985, letter.
The purpose of this Safety Evaluation is to address these other areas.
2.0 EVALUATION The licensee proposed removing the breaker trip setpoints from TS Table 3.8.2.6-1, removing the reference to the setpoints from the surveillance requirements and replacing the reference to the setpoints with the surveillance requirement that the breakers be tested as specified by NEMA AB-2-1980 ( the applicable standard against which the breakers are tested).
The basis for the circuit breaker trip setpoints in Table 3.8.2.6-1 is the protection of the electrical penetration from the effects of overcurrent. However, the values listed in the table correspond to the current at which damage to the connected load could occur. This amount of current is generally much lower that that at which damage to the penetration itself could occur. TS 3.8.2.6 requires that the associated equipment, in this specific case the drywell cooling fans, be deenergized if the trip setpoint listed in the table'cannot be met.
Such action would result in the loss of the unit due to high containment temperatures. The trip setpoints presently listed in the TS Table 3.8.2.6-1 are not based solely on protection of containment penetrations. The trip setpoints of the affected breakers are based on general guidelines designed to protect cables inside containment.
assuming a ground fault in the load.
Since the function of the motor is lost before the breaker opens, protection of the cables is an economic consideration rather than a safety consideration.
Therefore, changes to the setpoints do not affect plant safety as long as they provide protection for the penetration thermal capability (current'versus time limits) and allow sufficient current to be supplied to the loads.
Upon removal of the setpoints from the TSs, any changes to the presently calculated setpoints for the subject breakers will require a plant change review and safety evaluation in accordance with the requirements of 10 CFR 50.59. This review would address the design basis, which is protection of the penetration, as well as any other relevant engineering factors.. Thus, appropriate settings'for the breakers will be assured by.
a controlled design review process.
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NEMA AB-2-1980 requires thermal magnetic breakers be tested at 1275% of the continuous current rating followed by a test of 300% of breaker rating.
Magnetic only breakers are tested by use of a current at 141%
of the trip setpoint.
These parameters of multiplication are the same as our draft Standard Technical Specifications.
These tests will demonstrate that the breakers are operable at their specific setpoints.
The licensee has also proposed to change the parts number for item 13 on i
TS page 3/4-8-21 and the motor control center frame identification i
numbers for items 3 and 5 on TS page 3/4 8-21.
These are administrative changes made to correct the currently listed numbers.
Based on our review of the proposed changes as discussed above, we conclude that they are acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
i The amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and a change in surveillance requirements. We have determined that the amendment involves no significant increase in the amounts, and no.
significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or.
cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no.public comment on such finding.
Accordingly, the amendment meets the eligibility criteria for-categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 i
CFR 51.22(b), no environmental impact statement or environmental j
assessment need be prepared in connection with the issuance of the amendment.
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4.0 CONCLUSION
We have concluded, based on the considerations discussed above,-that:
(1) there is reasonable assurance that the health and safety of the public j
will not be endangered by operation in the proposed manner, and (2) such l
activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common l
defense and security or to the health and safety of the public.
Dated: January 9,1986 I
Principal Contributors:
S. Rhow, G. Rivenbark i
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