ML17341B228
| ML17341B228 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 06/04/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17341B227 | List: |
| References | |
| NUDOCS 8206160060 | |
| Download: ML17341B228 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISS)ON WASHlNGTOM,D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATEO TO AMENDMENT NO.
To FACILITY"OPERATING LICENSE NO.
DPR-41 FLORIDA POWER AND LIGHT COMPANY
'URKEY'POINT'LANT 'UNIT NO. 4 DOCKET NO. 50-251 Introduction By letter dated April 21, 19S2, Florida Power and Light Company (the licensee) requested an extension of four months to the operating interval of six months for the Turkey Point Plant Unit No. 4, Facility Operating License No, DPR-41.
The application was supported by the extensive inspection program and the conservative plugging program presented in the inspection results dated December 1S, 19Sl.
The program, conducted during the November outage, included denting inspections in the hot and cold legs of all the steam generators, flow slot measurements, small radius U-bend inspections, Regulatory Guide 1.03 inspections in hot and cold legs of all three steam generators and preventive
,plugging to permit ten months operation.
The staff had previously authorized two month extensions beyond six months operation during 1981 based on considerations that preventive plugging criteria implemented during the November 1980 steam generator inspection were more conservative than required to support six months operation.
The unit returned to power on December 10, 1981 and the end of the six month operational period will be June 1982.
Discussion CertMiel Bg The preventive plugging criteria implemented during the 19S1 steam generator inspection included the criteria which have been accepted by the NRC as being adequate to support six EFPM operation.
Since January 1979, the licensee has
. elected to perform additional preventive type 'plugging beyond what is required to support six EFPM operation.
This additional plugging has been.performed with the objective of supporting a ten EFPM operating intervalfor conservatism,
. as well as 'a contingency purpose.
)
The staff has previously expressed its reservations with regard to extending:
the methodology for preventive plugging to support a full ten EFPM operating interval.
The staff has been concerned that the methodology for anticipating which tubes will become susceptible to stress corrosion cracking and leaks during the next interval becomes increasingly uncertain as the length of interval is increased.
Therefor e, the staff has. continued to initially limit.
the authorized operating.interval following each inspection to six EFPM, with extended operation beyond six EFPM being approved only on a case by case basis based upon continued leak free performance during the initial six EFPM aad.the fact that the previously implemented plugging was more conservative than that required to support six EFPM operation.
820hi60060 820604 DESI ED O
INAL PDR ADOCK 0500025i P
Turkey Point Unit 4 has not expe'rienced denting related leaks since mid 1978.
The period since this time has included two ten EFPN intervals, Unit 4 has essentially completed its currently authorized six EFPH operating interval and is presently operating with slight indication of 0.01 gpm leakage in steam generator C.
This indication has been present during most of the current period of operation, has been relatively constant, and is significantly below the allowable 0.3 gpm limit in the Plant f.icense.
The licensee has stated that the behavior of this leakage to date is consistent with past experiences with "weeping" plugs.
In addition to denting, the Unit 4 steam generators have been subject to wasta'ge degradation.
The result of the November 1981 inspections for wastage attack revealed that tube wastage was occurring at a very minimal rate; a maximum thinning rate of 0.155 per EFPM was reported.
This rate results in an insignificant amount of tube wall loss for the proposed.ten EFPN operating interval.
Evaluation Our review of the results of the gauging inspections which included plugging for 10 months operations performed in November 1981 indicated that denting.
was continuing at a slower 'rate, consistent with previous experience at this and other. similarly degraded units..
Tube thinning rate for the period of
- January, 1981 through October 1981 had decreased from 1.77%
EFPN for the June 1980 - November 1980 operating period to 0.15K EFPH indicating possible improvements in water chemistry control.
The currently authorized six EFPM operating interval has essentially been comp1eted with no significant 'incr ease in the rate of leakage, In the event that'si"gnificant tube leakage does occur, the 0.3 gpm leakage rate limit in the Plant Operating License provides assurance that the plan't will be shutdown in a timely manner.
This limitation on allowable leakage rate provides reasonable assurance that the steam generator tubes will not develop excessive leakage during normal or postulated accident conditions.
The staff will continue to closely monitor the leak performance of the Unit, 4 steam generators.
Depending on the magnitude of any observed changes in detectable
- leakage, the staff will consider taking action to. require a reinspec-tion of the steam generators prior to the completion of ten months operation as an additional precautionary measure.
To this end, we are requiring that
'1) the staff.be notified immediately in the event of any. detectable trends in the indicated primary to secondary
- leakage, and (2) if the reactor is shutdown because of steam generator
- leakage, subsequent findings and any corrective actions shall be discussed with the NRC staff prior to the resumption of power.
Subject to the additional requiremehts described
- above, we conclude that
, operation of Turkey Point Unit 4 may be extended from six to ten effective'ull power months with reasonable assurance that public health and safety will not be adversely affected.
The licensee agrees with these requirements..
Environmental Consideration Me have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact.
= Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 51.5(d)(4),
that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion Me have concluded, based on the considerations discussed above that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously"considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the.
health and safety of the public will not be endangered by operation in the proposed
- manner, and
('3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date:
June 4, 1982