ML20117C379
| ML20117C379 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Turkey Point |
| Issue date: | 08/14/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20114F973 | List: |
| References | |
| FOIA-84-661 NUDOCS 8505090403 | |
| Download: ML20117C379 (6) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENOMENT N0.104 TO FACILITY OPERATING LICENSE NO. DPR-31 AND AMEN 0 MENT NO. 98 TO FACILITY OPERATING LICENSE _NO. OPR_-y FLORIDA POWER AN_0,_ LIGHT COMPANY TURKEY POINT PLANT, UNIT N05. 3 AND 4 i
DOCKET NOS. 50-250 AND 50-251 INTRODUCTION AND
SUMMARY
The criteria and staff positions pertaining to degraded grid voltage protection were transmitted to Florida Power and Light Company (FPL) by NRC Generic Letter dated June 3, 1977.
In response to this, by letters dated July 21, 1977, November 9, 1979, January 14, 1981 and May 10, 1982, the licensee proposed certain design modifications and changes to the Technical Specifications.
The staff and our consultant, Lawrence Livermore National Laboratory (LLNL), reviewed the submittals and provided the results and a request,for additional information in a letter dated O'ctober 28. 1982.
By letters dated Aucust 6, 1982, September 1,
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1982, January 3,1983, April 25,1983, January 31, '.582 anc Aoril 23, 1984, FPL submitted additional design changes, infonnation and Technical Specifications.
A d; tailed review and technical evaluation of these proposed modifications and changes to the Technical Specifications was performed by LLNL, This work is reported by LLNL in " Degraded Grid Protection for Class IE Power Systems Turkey Point Nuclear Generating Plant Units 3 and 4".
We have reviewed the submittals and concur with LLNL that the design of the degraded grid protection syster.; for Turkey Point Plant Units 3 and 4 meet the staff requirements and is therefore acceptable.
8505090403 841204 PDR FOIA DELL 84-661 PDR
EVALUATION CRITERIA The criteria used by LLNL in its technical evaluation of the proposed changes Include GDC-17 (" Electric Power Systems") of Appendix A to 10 CFR 50; IEEE Standard 279-1971 (" Criteria for Protection Systems for Nuclear Power Generating Stations"); IEEE Standard 308-1974 (" Class lE Power Systems for Nuclear Power Generating Stations");,and staff positions. defined in NRC Generic Letter to FPL dated June 3,1977.
PROPOSED CHANGES, MODIFICATIONS AND DISCUSSION The existing undervoltage protection at Turkey Point consists of:
Two instantaneous loss of voltage relays on each 4160 volt Class lE buses with a setpoint of 40 to 50% of nominal.
The two-out-of-two logic is such that actuation of one of the two relays on train "A" in conjunction with one
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of the two relays on train "B" will disconnect the offsite power source, initiate load shedding of the Class lE buses, start the emergency diesel and initiate load sequencing.
The load shedding feature is bypassed when the Class lE buses are being supplied by the diesel generators.
The following electrical system design modifications have been proposed by the licensee:
1.
Modify the existing loss of voltage relays so that the' relays of buses A and B are independent.
With these modifications actuation of both relays on bus A or bus B will initiate offsite source disconnection, load shedding, diesel generator starting and load sequencing only for the Aus an which the undervaltage randitloa occurs.
l 2.
Installation of two inverse time undervoltage relays on each 480 volt Class lE load center.
These relays will be connected in a two-out-of-two logic per bus and will provide protection against sustained degraded voltages under non-accident conditions. These relays will be bypassed when the diesel generator is supplying the Class lE buses.
3.
Installation of two instantaneous relays on each 480 volt Class lE load center.
These relays will be connected in a two-out-of-two logic and interlocked with a safety injection (SI) signal.
When actuated concurrent with an SI. these relays will initiate power source disconnection, diesel generator starting,1oad shedding and subsequent load sequencing.
we requested the lice.see provioe tne follow 1nc By letter dated October 28, 1982, r
additional infonnation:
t 1.
Details including. relay curves which show that tJ e 4160V and 480V degraded 1
voltage relays with time delays of 30
- 10 minutes will protect Class IE equipment from the effects of degraded grid voltage.
2.
In additior$ to the proposed Technical Specification changes, provide provisions which include:
a.
Surveillance requirements for the loss of voltage relays consistent with our June 3,1977 letter.
b.
Diesel generator test requirements which demonstrate the reinstatement of load shedding and load sequencing subsequent to a D/G breaker trip.
Th2 licensee has provided the technical specifications for the relay setpoints with tolerances, time delays, surveillance requirements and limiting conditions for tperation.
In addition, details were provided on how bypassing is accomplished by interlocking between the load-shed relays and the contact of the diesel breaker; and reinstatement of the load-shed feature when the diesel generator breaker trips.
The proposal of two imerse time undervoltate relays on each 4160 volt Class IE bus
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. was deleted and the 4160 volt Class 1E protection was modified with relays on the 480 volt Class 1E load center.
The licensee's submittals dated August 6, 1982 September 1, 1982, January 3, 1983, April 25, 1983, provided the necessary additional design details including the revised Technical Specifications.
We have reviewed the submittals and find that the degraded grid protection system as designed for Turkey Point 3 and 4 meet staff requirements and the voltage and time delay trip settings will protect the Class TE ecuioment from sustained degraded voltages under accident and non-accident concie:-
However, the licensee in letters dated January 31, 1984 and April 23, 1984 informer us that the proposed specification (two minimum operable channels) in the technica' specification could severely restrict operation in that it vould not allow maintenance of the aforementioned relays during operation.
Furthennore, the actior statement requires a cold shutdown of the plant if one of the two channels become inoperable.
The licensee feels that it is contrary to the original intent of the specification.
Consequently, the licensee proposed a revised Table 3.5-2 of the technical specifications with a footnote which states that operation or start-up may continue with only one channel operable subject to placing the inoperable channel in the trip condition.
In view of the fact that staff position requires performance or a regular cnanne' test (monthly) and calibration (every refueling), this amendment accomodates such provisions without disrupting plant operation by placing the inoperable channel in the trip mode.
The degraded voltage protection channel maintains 1-out-of-l logic on the affected bus while one channel is in the trip mode.
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In addition, the. licensee has proposed to increase the instantaneous setpoint by five volts on Table 3.5-4 to correct previously transmitted values.
The licensee determined that the new values more closely represent the designated tolerance of the relays.
These values are more conservative than those originally approved.
We therefore find the degraded grip pr;tection system and changes to Technical Specifications acceptable based on the details included in this Safety Evaluation and attached Technical Evaluation Report.
ENVIRONMENTAL CONSIDERATION These amendments involve a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that these 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 significant increase in individual or commulative occupational radiation exposure.
The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding.
Accordingly, these amendments meet the eligibility criteria for categorical exclusion set forthinCFR51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
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O 6-CONCLUSION We have concluded, based on the considerations' discussed above, that:
(1) there is reasonable assurance that the health and safety of the public wiIl not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the C'ommission'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:
Date: August 14, 1984 Attachments:
As stated Principal Contributors:
P. Kang D. Mcdonald b\\
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