ML20069Q446
| ML20069Q446 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/03/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20069Q443 | List: |
| References | |
| NUDOCS 9101160050 | |
| Download: ML20069Q446 (4) | |
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Et: CLOSURE A SAFETY EVAll't.T10N BY THE OFFICE OF NUCLEAR REACTOR FEGULATION SUPPORTING AMENDfjtf!T NO.178 TO FACILITY OPERATING LICENSE NO. OPR-33 AMEND 9ENT NO.184 TO FACILITY OPERATING LICENSE NO. DPR 52 AMENDMENT NO.149 TO FACILITY Ot!LATING LICENSE NO. DPR-68 TENNFSSEE VALLEY AUTHORITY j
BROWNS FERRY NUCLEAR FLANT, UNITS 1. 2 AND 3 DOCKET NOS. 50 259, 50-260 AND 50-296 1.0 1HTR000CT10H By letter dated August 7, 1970 the NRC advised the Tennessee Valley Authority (TVA or the licensee) of deficiencies regarding tv., Reactor protection System (RpS) Power Monitoring System (PMS) identified at Hatch Nuclear plant, Unit 2, and the potential for similar deficiencies at other Boiling Water Reactors (WRs). The NRC requested that TVA evaluate the design of the Browns Ferry Nuclear rower Plant (BFN) RPS and promptly commence surveillance of the RPS power supply as described in the letter.
By letter dated December 13, 1978, the licensee responded that the proposed RpS modifications were not necessary and that additionel Technical Specification (TS) changes were not planned. The licensee's letter also advised the NRC that the surveillance requirement imposed by the August 7,1978, letter would be discontinued af ter January 1, 1979. The NRC's letter of September 24, 1980, advised TVA that based on the NRC's evaluation, BFN could experience the some adverse conditions found at Hatch, Unit 2, and modifications should be implemented at BFN with specified TS.
By letter dated July 1,1981, TVA provided the general outline of the design approach for the requested modifications, proposed TS limits were submitted as part of the Unit I reload.
However, the reload submittels from TVA did not provide sufficient information to substantiate design conformance to General Design Criteria (GDC) 2, GDC 21 and IEEE 279-1971.
Also the proposed trip set-aoints of the protective relays were not based on analysis and test verification.
By letter dated October 12, 1983, the NRC transmitted these concerns to TVA, and the subsequent response dated August 9, 1984, resolved some issues. A request for additional information was sent to TVA on October 31, 1984 to which TVA respondec' by letter dated March 1,1985. The NRC's Safety Evaluation (SE) on these modifications was issued on July 27, 1985.
According to the SE, the NRC accepted the modifications and required that the licensee submit the revised TS after completion of the testing of design modifications, By letter dated and also include the test verified relay setpoint and time delays in the TS.
December 22, 1988, TVA submitted this information to the NRC. The NRC reviewed the information and approved the TS amendment for BFN Unit 2.
However, the plant experienced spurious trips due to transient conditions.
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i Consequently in a June 4, 1990 letter, the licensee requested approval of the i
proposed amendment for the new setsoints for RPS circuit protection dsvices.
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The proposed amendment would (1) clange the RPS circuit protection trip level l
setpoints for Unit 2, (2) add surveillance requirements 4.1.B.2 to the Units 1 I
and 3 TS with the new setroints, (3) add surveillance requirement 4.1.B.1, which contains the new setpoints to Unit 3, and (4) add limiting conditions for operation 3.1.B.1 and 3.1.B.2 to the tinit 3 TSs.
j The October 24 1990 letter provided clarifying information that did not changetheactiondescribed or the initial determination of no significant hazards consideration as pre,viously published in the FEDERAL REGISTER.
In addition, a grammatical change to TS 3.1.B. aIthough not mentioned in the initial FEDERAL REGISTER notice, similarly did not alter the action or affect the initial determination.
2.0 EVALUATION
,4 The previous values for the RPS circuit protection devices were as follows:
Allowable TS Limit Trip Setpoint Overvoltage 126.5 124.5 l
Undervoltage (Motor Generator (MG) Set) 113.4 115.0 Undervoltage 111.8 115.0 Underfrequency(Alternate Supply) 57.0 58.0 The new values proposed in the June 4, 1990, submittal for the RPS circuit protection devices are as follows:
Allowable TS Limit Trip Setpoint l
Overvoltage 132.0 129.09 l
Undervoltage 108.5 110.46 Underfrequency 56.0 57.0 The annunciator setpoint for overvoltage is set at 124.5 volts and for undervoltage it is set at 115 volts. Thereisnoannunciatorforthe underfrequency condition.
I The NRC expressed a concern with the amendment request.
The concern related to the new setaoints that may require some equipment to operate beyond their design-ratings.
Tie NRC made a request for additional infomation on September 27, 1990.
TVA provided the additional infomation on October 24,1990. The NRC reviewed the information and, during a November 15, 1990 conference call, asked TVA to provide more infomation related to all the spurinus trips associated with the PMS and a list of all the RPS components together with their design ratings and calculated values of the parameters based on the new trip set-
_ points.
During a meeting on November 27,1990 TVA presented this infomation to the NRC staff. The current setpoint and alam for undervoltage and overvol-tage condition would not allow the operator enough time to take corrective action to prevent a spurious trip. According to TVA, the only components with
3-environmental qualification (EQ) requirements are ASCO solenoid valves, but since these valves do not operate beyond their design ratings, their qualifice-tion would not be affected. TVA has also received letters from two manufac-turers stating that the equipnient can operate withcut degradation at the calculated values, which are beyond their design ratings. The calculated values do not exceed the design ratings by more ther : 3 Volts and should not affect equipment performance.
For underfrequency all the comsonents operate within their design ratings except for two corponents for which tie allowable undctfrequency exceeds the rated fre-quency by 1 cycle per second. However, since these components (MG sets) contain a large flywheel, the equipment should not see a significant frequency variation, except when there is a power source switchover for an PG set due to a bus f ault.
Based on the above evaluation, the NRC concludes that the new setpoints will not adversely impact the equipent and will improve plant reliability.
The new setroints are reflected in revisions to surveillance requirement 4.1.E.2 for Units 1 and 2.
For consistency with the other two units, the Unit 3 TS were revised to include surveillance requirements 4.1.B.1 and 4.1.B.2, and the associated LCOs 3.1.B.1 and 3.1.B.2, with the appropriate setpoints and adequate surveillance intervals to ensure plant safety and improve plant reliebility. These changes are thus acceptable.
In addition, an editorial change-te correct the grammar of LCO 3.1.B for Units 1 and 2, although reflected in the proposed TS pages, but not discussed in the licensee submittal, is also acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
The amendments involve changes to requirements with respect to installation or use of a f acility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements. The staff has detennined that the amendments involve 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 si occupational radiation exposure.gnificant-increase in individual or cumulative
- The Commission has previously issued a pro-posed finding that these amendments involve no significant hazards considera-tion and there has been no public comment on such finding. Accordingly, the amendn.ents meet'the eligibility criteria for categorical exclusion' set-forth in 10CFR51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
The Commission made a proposed determination that the amendments involve no' significant hazards consideration, which was published in the FEDERAL REGISTER (55 FR 30314) on July 25, 1990, and consulted with the State of Alabama.
No public consents were received and the State of Alabama did not have any com-ments. The State of Alabama was also informed of the staff's final no signi-ficant hazards consideration determination and the intent to issue a license anendment.
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4 The staff has concluded, bestd on the considerations discussed above, that:
(1) there is reasonable assurance that the health and sefety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, i
I and (3) the issuance of the amendments will not be inimical to the common defense and security nor to the health and safety of the public.
Principal Contributor:
H. Garg Dated: January 3,1991 l
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