ML20136F542
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UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
j WASHINGTON, D. C. 20666 9....,8
'4 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FLORIDA POWER AND LIGHT RESPONSE TO GENERIC LETTER 90-06 ST. LUCIE UNITS 1 AND 2 DOCKET N05, 50-335 AND 50-389
1.0 INTRODUCTION
By letters dated December 29,1990, (Ref.1), December 6,1991 (Ref.2), May 11,1992, (Ref.3), and October 9,1992 (Ref. 4), Florida Power and Light (FPL),'the licensee for the St. Lucie Units 1 and 2, responded to the recommendations of Generic Letter 90-06 (GL 90-06). Additional information was docketed August 3, 1993 (Ref. 5).
GL 90-06 deals with the resolution of Generic Issues 70 and 94, (GI-70, GI-94) on " Power Operated Relief Valve andi Block Valve Reliability" and " Additional Low-Temperature Overpressure Protection for Light Water Reactors".
The submitted information describes the existing hardware at the St. Lucie plants, the corresponding operating procedures and the actions taken to comply with the GL 90-06 recommendations.
1 2.0 EVALUATION GI 90-06 (Ref. 6) provides the resolution for two generic issues; GI-70,
" Power Operated Relief Valve and Block Valve Reliability" and GI-94, l
" Additional Low-Temperature Overpressure Protection for Light Water Reactors".
The GL 90-06 recommendations for each of the generic issues and FPL's response will be preseated and evaluated in the following.
97031401i@ 970301 PDR FOIA BINDER 96-485 PDR
i 2.1 Power Ooerated Relief Valve and Block Valve Reliability The resolution of GI-70 was based on staff work reported in NUREG-1316 (Ref.
7), and is based on recommended improvements and technical specification changes.
The first recommended action is to " include PORVs and Block Valves within the scope of an operational quality assurance program that is in compliance with 10 CFR part 50, Appendix B.
This action includes three
-elements: (1) operational quality assurance, (2) maintenance and refurbishment and (3) replacement and spare parts.
FPL complied with all elements of this recommendation. The second recommendation is related to in-service testing, and also consists of three elements: (1) PORVs and Block Valves be included in the ASME Boiler and Pressure Vessel Code Section XI, Subsection IWV (2) PORV t
stroke testing should only be performed in Modes 3 or 4, (hot standby or hot shutdown respectively) and (3) block valves should be included in the MOV test program discussed in GL 89-10.
FPL has taken exception to the stroke testing recommendation in Modes 3 or 4.
The justification for this position is; (1) in the case of St. Lucie the l
amount of steam in the space between the block valve and the PORV is not enough for PORV testing, thus, stroke testing requires open block valves which is equivalent to a small break LOCA; (2) the St. Lucie PORVs are pilot operated valves (as oppored to electromagnetic relief valves assumed in GL 90-06) using reactor pressure as the motive power, thus, successful testing at lower temperatures and pressures would provide reasonable assurance that the-valves function properly at higher pressures; (3) the PORVs are not part of the accident management strategy as a means of RCS depressurization in the sense that the E0Ps do not call for the use of the PORVs in depressurization.
(the Emergency Operating Procedures (EOPs) have been based on CEN-152 Revision 3 (Ref. 8) which has received conditional staff approval (Ref. 9)), (4) emergency depressurization is accomplished using pressurizer sprays with safety grade equipment and (5) these methods are part of the St. Lucie licensing bases.
- GL 90-06 states that the recommended actions represent a new staff position and they are a cost justified backfit.
However, GL 90-06 refers to plants which use the PORVs to perform a number of safety related functions.
In older plants PORVs and the associated block valves were not safety grade equipment.
In St. Lucie all of the GL 90-06 safety related functions are accomplished without using the PORVs, instead using the pressurizer sprays which is safety grade equipment.
The E0Ps do not involve PORVs in accident management.
Essentially, St. Lucie employs the same means for depressurization as other CE plants which do not have PORVs (Ref. 4).
Therefore, we find that the intent of GL 90-06 does not cover St. Lucie, thus, the exception from PORV testing in Modes 3 or 4 is acceptable.
The third recommendation is modification of the technical specifications, with the overall objective of reducing the likelihood of an accident by reducing reactor operation time with inoperable PORVs and block valves.
FPL did not consent to implementing these technical specifications, because neither the PORVs or the block valves are credited with the mitigation of any accident conditions.
We find that the intent of GL 90-06 does'not cover the St. Lucie plant which uses other, safety grade equipment to accomplish the functions described in the generic letter.
Thus, the staff finds that FPL's position to not implement the proposed technical specifications is acceptable.
2.2 GI-94
Additional low Temperature Overoressure Protection for liaht Water Reactors GL 90-06 showed that LTOP protection system unavailability is the dominant j
contributor to the occurrence of LTOP transients.
The staff has further concluded that substantial improvement in availability of LTOP protection devices when the potential for an overpressure event is the highest and especially water solid operation, can be achieved through improved administrative restrictions on the LTOP system.
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_4 2.2.1 GI-94, St. Lucie, Unit 1 The licensee stated that "FPL will submit a change to the LTOP Technical Specifications similar to the GL recommendations for St. Lucie Unit 1, within one year of receipt of the staff acceptance of the proposed plans for implementation of the GL recommendations".
In view of the favorable overpressurization record of the St. Lucie plants (never experienced an overpressurization event) and the extremely low estimated core disruption frequency (CDF) due to LTOP, we find the proposed implementation schedule for the GL technical specification, acceptable.
2.2.2 GI-94 St. Lucie, Unit 2 The existing St. Lucie, Unit 2, technical specifications have language differences with the technical specifications proposed in the generic letter but they are essentially the same.
One of the differences arises from the fact that St. Lucie 2, has more than two depressurization devices available; two PORVs and two shutdown cooling relief valves.
Another difference is in action statement (d) in the Generic letter, for which an equivalent statement is in the surveillance requirements of the St. Lucie, Unit 2 technical specifications.
We find that the existing St. Lucie 2 technical specifications fulfill the intent of GL 90-06 and, therefore, the existing technical specifications are acceptable.
3.0
SUMMARY
AND CONCLUSIONS We have reviewed the information submitted by FPL, in response to GL 90-06 regarding the St. Lucie plant.
For the reasons stated above, we find that the FPL response is in compliance with the intent of Generic Letter 90-06, therefore, we find it acceptable.
This conclusion is based on:
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GI-70; the fact that both St. Lucie Units have the same type of depressurization safety grade equipment as plants which have been licensed to operate without PORVs, and' i
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GI-94; Unit 1 is committed to propose technical specifications, within a l
year of the acceptance of this evaluation, which are equivalent of those proposed by GL 90-06, and Unit 2 has technical specifications which satisfy the intent of GL 90-06.
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4.0 REFERENCES
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- 1. Letter from W.H. Bohlke, Florida Power and Light to US Nuclear Regulatory Commission, " Resolution of Generic Issues 70 and 94" December 20, 1990 (L-90-435)
- 2. Letter from D.A. Sager, Florida Power and Light to US Nuclear Regulatory l
Commission, " Supplemental Response to Generic Letter 90-06" December 6, 1991 (L-91-327)
- 3. Letter from D.A. Sager, Florida Power and Light, to US Nuclear f
Regulatory Commission, " Supplemental Response to Generic Letter 90-06" May
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11, 1992 (L-92-134)
Units 1 and 2 Generic Letter 90-06, Generic Issues 70 & 94" August 3, 1993.
- 5. Letter from D.A. Sager, Florida Power and Light to US Nuclear Regulatory Commission, " Generic Letter 90-06 Supplemental Response", October 9,1992 j
(L-92-288) i
- 6. GL 90-06, " Resolution of Generic Issue 70, " Power Operated Relief Valve and i
Block Valve Reliability" and Generic Issue 94, " Additional Low-Temperature Overpressure Protection for Light Water Reactors", Pursuant to 10 CFR j
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1 50.54(f)"
Issued June 25, 1990.
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- 7. NUREG-1316, " Evaluation of Power-0perated Relief Valve and Block Valve Reliability in PWR Nuclear Power Plants",
R. Kirkwood U.S. Nuclear Regulatory Commission, November, 1988.
- 9. Letter from F. Miraglia to J.K. Casper, Combustion Engineering Owners Group, August 2, 1988.
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SYSTEMATIC ASSESSMENT OF LICENSEE PERFORMANCE I
1 FACILITY NAME:
St. Lucie, Units 1 and 2.
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SUMMARY
REVIEW:
This review addressed the Florida Power and Light's response to the requirements of Generic letter 90-06.
There are two issues in this review:
(1) GI-70 " Power Operated Relief Valve and Block Valve Reliability " and GI 94 " Additional Low Temperature Overpressure Protection for Light Water f
Reactors" NARRATIVE DISCUSSION OF LICENSEE PERFORMANCE-SAFETY ASSESSMENT /0VALITY VERIFICATION The information submitted was adequate and sufficiently described the justification for their action.
Request for discussion and clarification were responded to promptly and accurately. The licensee has installed adequate i
depressurization capability as to have addressed all of the GL 90-06 concerns.
Licensee performance was excellent.
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AUTHOR:
L. Lois DATE:
8/4/'93 l