ML17348A830
| ML17348A830 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point, Saint Lucie  |
| Issue date: | 01/23/1991 |
| From: | Aukuck R, Norris J Office of Nuclear Reactor Regulation |
| To: | Goldberg J FLORIDA POWER & LIGHT CO. |
| References | |
| REF-GTECI-046, REF-GTECI-NI, TASK-046, TASK-46, TASK-OR GL-87-02, GL-87-2, TAC-68303, TAC-68304, TAC-69483, NUDOCS 9101280087 | |
| Download: ML17348A830 (10) | |
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UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 January 23, 1991 Docket Nos.
50-335 I50-2502and 50-251 Mr. J.
H. Goldberg President-Nuc1ear Division Florida Power and Light Company P.O.
Box 14000 Juno Beach, Florida 33408-0420
Dear Mr. Goldberg:
SUBJECT:
REVIEW OF FPL'S FINAL IMPLEMENTATION PROGRAM IN RESPONSE TO GENERIC LETTER 87-02 REGARDING THE VERIFICATION OF SEISMIC ADEQUACY OF EQUIPMENT AT ST.
LUCIE UNIT 1 AND TURKEY POINT UNITS 3 5 4 (TAC NOS.
- 69483, 68303, AND 68304)
On August 4, 1989, the NRC staff issued a letter providing the results of review of the preliminary plant-specific implementation program proposed=by the Florida Power and Light Company (FPL) in response to Generic Letter (GL) 87-02.
In this letter, the staff requested that additional information concerning pre-walkdown requirements be submitted for staff review and approval on or before September 30, 1989.
In response to the August 4, 1989 letter, FPL submitted its final implementation program on December 13, 1989.
In this letter, FPL stated that it would schedule implementation of the proposed program at Turkey Point Unit 3 and St. Lucie Unit 1 during their spring 1990 refueling outages if the NRC Safety Evaluation (SE) was received by January 30, 1990.
Otherwise, FPL expected to implement the program at the next refueling outage for St. Lucie Unit 1 and during the Emergency Power System enhancement outage for Turkey Point Units 3
8 4 in 1991.
Because of a staff resource problem at the time, the staff was unable to issue the SE by January 1990.
The staff has now completed its review of FPL's December 13, 1989 letter, "Plant Specific Seismic Adequacy Implementation Procedure to Resolve Unresolved Safety Issue (USI) A-46 and Generic Letter (GL) 87-02, Revision 1."
Basically, FPL did not provide sufficient information in response to the August 4, 1989 request and the staff cannot approve FPL's final implementation program for the reasons suIIIIarized below and described in detail in the enclosure to this letter.
1.
Specifically, the information requested for pre-walkdown items (2),
(4), (5) and (6) in the NRC August 4, 1989 letter is either too sketchy or not provided.
In item (2),
FPL should describe in-4etail the assu 44ens-made and the shutdown.
ath s-chosen together wihM%e associa e
s u
own ui ment-Ws nc u
ng equipment floor elevation).
In items (5) and s
ou d provide detailed criteria and procedures for the evalua-tion of seismic system inFeracHon equipment anchorage and the essential relays.
If the "anchorage design basis requirements",
as mentioned in the submittal, are to be used, describe those requ'trements 4a-detab.l, such as anchor strength, factor of safety for different types o~o ~s, ow to
- account for the effects of edge distance, spacing and cracked concrete, etc.
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Mr. J.
H. Goldberg 2
January 23, 1991 2.
With respect to FPL's request for exclusion of relay evaluation from the plant-specific implementation (pre-walkdown item (4)), the staff finds that the request is unacceptable for reasons given in the enclosure to this letter.
Therefore, we have concluded that your December 13, 1989 final implementation program is not totally acceptable.
- However, we understand that you have expedited your schedule, as stated in the December 13, 1989 letter, and have conducted some plant walkdowns.
We believe that you may be able to credit that completed effort toward meeting the requirements of GL 87-02, if that work was completed using procedures and criteria acceptable to the staff.
We request that FPL submit the detailed information requested in connection with Items I and,2 above, together with a summary report describing the work completed so far.
This information will enable the staff to judge whether or not the procedures and criteria used for the walkdown and the results obtained so far are acceptable.
Please submit the requested information on or before February 28, 1991.
This requirement affects fewer than 10 respondents and, therefore, is not subject to Office of Management and Budget review under P. L.96-511.
Original signed by Jan A. Norris, Senior Project Manager Project Directorate II-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
As stated Sincerely, Original signed by Rajender Auluck, Project Manager Project Directorate II-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation cc w/enclosure:
See next page DISTR'UT-ION.
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St. Lucfe Unit 182 Turkey Point Units 354 CC:
Mr. Jack.Shreve Office of the Public Counsel Room 4, Holland Building Tallahassee, F1orida 32304 Senior Resident Inspector St. Lucfe Plant U.S. Nuclear Regulatory Commission 7585 S.
Hwy A1A Jensen
- Beach, Florida 33457 State Planning 5 Development Clearinghouse Office of Planning 8 Budget Executive Office of the Governor The Capitol Building Tallahassee, Florida 32301 Harold F. Reis, Esq.
Newman 8 Holtzfnger 1615 L Street, N.W.
Washington, DC 20036 John T. Butler, Esq.
- Steel, Hector and Davis 4000 Southeast Ffnancfal Center Miami, Florida 33131-2398 Adminfstrator Department'of Environmental Regulation'ower Plant Siting Section State of Florida 2600 Blaii Stone Road Tallahassee, Florida 32301 Mr. James V. Chisholm County Administrator St. Lucie County 2300 Virginia Avenue, Room 104 Fort Pierce, Florida 33450 Mr. Charles B. Brfnkman, Manager Washington Nuclear Operations Combustion Engineering, Inc.
12300 Twinbrook Parkway, Suite 330 Rockville, Maryland 20852 Plant Manager Turkey Point Nuclear Plant Florida Power and Light Company P. 0.
Box 029100 Miami, Florida 33102 Mr. Jacob Daniel Nash Office of Radiation Control Department ot Health and Rehabilitative Services 1317 Winewood Blvd.
Tallahassee, Florida 32399-0700 Regfonal Admfnistrator, Region II U.S. Nuclear Regulatory Comfssfon 101 Marietta Street N.W., Suite 2900 Atlanta, Georgia 30323 Mr. Thomas F. Plunkett, Site Vice President Turkey Point Nuclear Plant P. 0.
Box 029100 Miami, Florida 33102 Joaquin Avfno County Manager of Metropolitan Dade County ill NW 1st Street, 29th Floor Mfamf, Florfda 33130 Senior Resident Inspector U.S. Nuclear Regulatory Commission Turkey Pofnt Nuclear Generating Station Post Office Box 1448 Homestead, Florida 33090 Attorney General Department of Legal Affairs The Capitol Tallahassee, Florida 32304 Intergovernmental Coordination and Review Office of Planning 8 Budget Executive Office of the Governor The Capitol Building Tallahassee, Florida 32301
I l
ENGLQSURE.
NRC-STAFF REVIEW-OF RE VEST-FOR-EXCLUSION-OF -RELAY-EVALUATION FROM-THE RLANT-SRECIFIG EVALUATION-OF GENERIC -E,ETTER-87-02.
ST;-GUCN -UNIT-i-DOCKET-NO> 336 TURKEY-POINT ---UNiT DOCKET NO;-50-250 TURKEY--POINT -UNIV DOCKET-NO-r-50-251 FLORIDA - POWER-AND -L;IGHT COMPANY Appendix A of the licensee's December 13, 1989 submittal provided the licensee's technical and economic bases for the exclusion of relays from their program.
We provide one clarification to the licensee's statement that GL 87-02 has seismic criteria which require that relays be functionally free from chatter for a period of 30 seconds of shaking motion.
The clarification fs that the chatter -free requirement applies only to that equipment for which chatter is unacceptable.
This clarification removes many relays from consideration.
Appendix A of the submittal provided a summary of the licensee's conclusions.
Conclusion 1 states that strong shaking of any duration fs not credible for these plants.
The staff disagrees for the following reasons.
The FSAR for St. Lucfe Unit 1 states that the Safe Shutdown Earthquake (SSE) ground motion for,seismic design is 0. 10g, the FSAR for Turkey Point states that the SSE is 0.15g.
For plants in the eastern United States, the SSE is usually defined as the historic earthquake of greatest magnitude or intensity in the tectonic province in which the plant is located.
The acceleratfons at the site are determined assuming that these earthquakes occur at the site.
Recently both the NRC (through Lawrence Livermore National Laboratory (LLNL))
and the nuclear power industry (through the Seismic Owners Group/Electric Power Research Institute (SOG/EPRI))
have developed probabilistfc seismic hazard values for nuclear power plant sites in the eastern U.S.
The LLNL hazard results include all operating plants in the eastern U.S.
The SOG/EPRI results include only 57 of those sites and neither St. Lucie nor Turkey Point fs among them.
The LLNL results show that the probability of exceeding the'esign basis SSE is as follows:
St. Lucie, SSE
= 0.10g, MEAN ANNUAL PROB.
OF EXCEEDANCE = 6X10 Turkey Point, SSE
= 0.15g, MEAN ANNUAL PROB.
OF EXCEEDANCE = 1.3X10
V I Large variations in the mean hazard are a reflection of the large uncertain-ties that are inherent in the seismic hazard methodology.
However, the relative'differences between mean hazards for the Florida plants and other plants along the eastern seaboard range from a factor of 2 to 10, with the Florida plants having the lower probability of exceedance.
The FSAR for Turkey Point does not specifically address the floor response spectra resulting from a ground motion of 0; 15g.
The FSAR for St. Lucie Unit I specifically addresses the floor response spectra.
The maximum calculated accelerations appear to range from 1.35g (1-2 Hz) at elevation 206.5 for horizontal motion and 1.35g (2-4 Hz) at elevation 60 for vertical motion in the reactor building, to 3.0g (2-4 Hz) at elevation 81 for horizontal motion in the auxiliary building.
The SSE spectral acceleration for horizontal ground motion for St. Lucie (FSAR Figure 3.7-3) in the 2-4 Hz frequency range is approximately 0.3g.
Hence the maximum amplification appears to be around 10 (auxiliary building).
Since the occurrence of an earthquake comparable to the SSE is of about the same likelihood for these two plants as for other. plants in the eastern U.S., in a statistical sense as well as a deterministic
- sense, strong shaking at higher floor elevations fn the range of lg to 3g should be considered possible.
In Conclusion 2 of the submittal, the licensee is referencing the qualification of St. Lucie, Unit 2 under IEEE 344-75/RG
- 1. 100 Rev.
1.
The licensee states that neither the IEEE or RG documents require relay chatter during strong shaking to be addressed.
The staff agrees with that statement but notes that IEEE 344-75 (Section
- 4) does require that an equipment's ability to perform its required function during and after the time it is subjected to the forces resulting from one SSE be demonstrated.
The staff considers that if relay chatter prevents required equipment from performing its function when it is required to perform (or unacceptable inadvertent actuation),
then the requirements of IEEE 344-75/RG 1.100 have not been met.
Conclusion 3 addresses the requirement for future plants of 15 seconds of strong shaking.
The staff position for USI A-46 plants is the same as that for the future plants.
The 30 seconds is the total duration which includes a minimum of 15 seconds strong motion portion of the earthquake, 5 seconds ramp and 10 seconds delay.
Conclusion 4 states that seismic PRAs completed to date did not assign any risk contribution to core melt from relay chatter.
The staff notes that past PRA practice does not preclude consideration of relay chatter es part of GL 87-02.
As noted by the licensee, GL 87-02 was approved as a backfit, and does not require generation of a PRA with relay chatter considered.
The licensee also mentions equipment failure recoverable by operator action.
The staff accepts operator actions if the feasibility of such operator actions can be demonstrated.
4 4
Conclusion 5 states that NUREG-1211 (A-46 Regulatory Analysis) did not assign a
r isk contribution to core melt from relay chatter.
Although a quantitative number was not assigned, a value-impact analysis with qualitative assessment was made and the requirement to consider relay chatter was approved as' backfit as part of GL 87-02.
Conclusion 6 addresses past studies at St. Lucie and Turkey Point.
Those studies were not related to the resolution of USI A-46.
Conclusion 7 states that NRC-approved criteria for the purpose of evaluating relays 'under the A-46 program do not exist.
The staff,has generally approved the methodology developed by the Seismic gualification Utility Group (SOUG).
The criteria do not,require access to the SHRUG data base and methodology.
Alternatives to the SHRUG methodology for relay review are the criteria of IEEE 344-1975 and IEEE 501 standards, which are acceptable for the relay evaluation.
Conclusion 8 states that required expenditures by FPL to address relays would not be prudent.
- Relays, anchorages, and elements which are outside of the experience data were identified as the three most significant potential areas which could be impacted by a seismic event (Ref.
GL 87-02, NUREG-1211 and NUREG-1030).
Since strong shaking is determined to be a credible event at FPL facilities, relay chatter must be considered.
The December 13, 1989 submittal also provides a discussion of the FPL conclu-sions.
Discussion 2 addresses relays which malfunctioned during the Perry earthquake but which probably would not have malfunctioned if energized.
The staff notes that Perry was licensed to current (IEEE 344-1975) criteria.
No comparison was submitted by FPL which showed that the Perry experience of all systems functioning normally is relevant and applicable to the equipment in the FPL plants.
Discussion 4 addresses the relay evaluation efforts.
The staff believes that comparison of relays to the Generic Equipment Ruggedness Spectra (GERS) data is an acceptable-approach for A-46 resolution.
The extrapolation of the GERS data to similar relays is currently being evaluated by SHRUG and the staff.
The staff believes that the existing GERS will envelope many of the'relays that need to be considered, The staff agrees with the FPL comment that demonstration of similarity and application of GERS on a generic basis may be difficult.
This potential difficulty does not preclude performing the evaluation.
As noted in the value-impact analysis of NUREG-1211, backfit analysis for correction of any deficiency will be performed on a case-by-case basis if the need arises following completion of the review.
/
In summary,'he staff has concluded that relay chatter must be considered and evaluated at the FPL facilities.