L-90-435, Forwards Response to Generic Ltr 90-06 Re Resolution of Generic Issue 70 on PORV & Block Valve Reliability & Generic Issue 94 on Addl Low Temp Overpressure Protection
| ML17223B036 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 12/20/1990 |
| From: | Bohlke W FLORIDA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-070, REF-GTECI-094, REF-GTECI-NI, TASK-070, TASK-094, TASK-70, TASK-94, TASK-OR GL-90-06, GL-90-6, L-90-435, NUDOCS 9012260152 | |
| Download: ML17223B036 (14) | |
Text
ACCELERATED D> TRIBUTION DEMONS RATION SYSTEM I
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9012260152 DOC.DATE: 90/12/20 NOTARIZED: YES FACIL:50-335 St. Lucie Plant, Unit 1, Florida Power
& Light Co.
50-389 St. Lucie Plant, Unit 2, Florida Power
& Light Co.
AUTH.NAME AUTHOR AFFILIATION BOHLKE,W.H.
Florida Power
& Light Co.
RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
DOCKET, g 05000335 05000389 R
I SUBZECT: Forwards response to Generic Ltr 90-06 re resolution of Generic Issue 70 on PORV
& block valve reliability & Generic D
Issue 94 on addi low temp overpressure protection.
S DISTRIBUTION CODE:
A019D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: Generic Ltr 90-06 Resolution of GE 70N94 PORVs
& Block Valve Rely.abil NOTES:
RECIPIENT ID CODE/NAME PD2-2 LA NORRIS,J COPIES LTTR ENCL 1
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1 RECIPIENT ID CODE/NAME PD2-2 PD COPIES LTTR ENCL 1
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RPSIB EXTERNAL: NRC PDR 1
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1 NRR/EMEB PICKETT,D 13H15 RES/DSIR/EIB NUDOCS-ABSTRACT 1
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D NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
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LTTR 12 ENCL 12 D
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PO.Box14000,Juno Beach,FL 33408-0420 U.S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, D.C.
20555 OECEMBER 2 0
$ 9SO L-90-435 10 CFR 50.54 (f)
Gentlemen:
Re:
St. Lucie Units 1 and 2
Docket Nos.
50-335 and 50-389 Resolution of Generic Issues 70 and 94 Generic Letter 90-06 By Generic Letter 90-06 (GL 90-06),
dated June 25,
- 1990, the staff forwarded to its licensees its recommendations concerning the resolution of Generic Issue 70 (GI 70),
"Power-Operated Relief Valve and Block Valve Reliability," and Generic Issue 94 (GI 94),
"Additional Low-Temperature Overpressure Protection for Light-Water Reactors.
The staff requested that licensees respond to the recommendations made in GL 90-06 and advise them of the current status of plans relating to power-operated relief valves (PORVs) and block valves.
A description of the actions which have been taken to date in response to improvements 1,
2, and 3
as described in Section 3.1 of Enclosure A of GL 90-06 is provided in Attachment 1 to this letter.
Additional information pertinent to the St. Lucie units'ORVs is provided in Attachment 2 to this letter.
The staff also requested that it be informed of licensees'ntentions to submit a
license amendment request to modify the technical specifications and commit to use of the modified technical specifications recommended in Attachment B-1 of Enclosure B to the generic letter.
FPL is evaluating the staff's recommendations for low-temperature overpressure protection (LTOP) system limiting conditions for operation for applicability to the St.
Lucie units.
Additional information pertinent to this evaluation and its completion date are also provided in Attachment 2 to this letter.
Should you have any questions, please contact us.
Very truly yours, W.H.
lke Vice President Nuclear Engineering and Licensing WHB/JMP/klw att.
DAS/PSL 8302 cc:
Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector<
USNRC, St. Lucie Plant 9012260152 901220 PDR ADOCK 05000335 p
PDR 2 'B
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STATE OF FLORIDA
'OUNTYOF PALMBEACH W.H. Bohlke, being first duly sworn, deposes and says:
That he is Vice President - Nuclear Engineering and Licensing ofFlorida Power and Light Company, the Licensee herein; That he has executed the foregoing document; that the statements made in this document are true and correct to the best ofhis knowledge, information, and belief, and that he is authorized to execute the document on behalf of said Licensee.
W.H. Bohlke Subscribed and sworn to before me this day of 19 ~O 4
QI II g'g
)
(-
4 gV Notary Public, in and for the County ofPalm Beach, State ofFlorida ttOTARY PUBLIC STATE OF FLORIDA HY CGt"4ISSIOtl EXP JULY 30,1994 orntLission exPires BOttBEO THRU GEHERAL IttS. Ut'0.
Y
FLORIDAPOWER ANDLIGHT St. Lucie Units 1 and 2 hmn 1
GENERIC LE<TTER 90-06 PROPOSED ACTIONS AND RESPONSE SCHEDULE Florida Power and Light (FPL) proposes to take the followingactions in response to the recommendations promulgated by the staff in Generic Letter 90-06 (GL 90-06):
R mmend Action 1 1.
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 program should include the followingelements:
The addition ofPORVs and block valves to the plant operational Quality Assurance List.
b.
C.
Implementation of a maintenance/refurbishment program forPORVs and block valves that is based on the manufacturer's recommendations or guidelines and is implemented by trained plant maintenance personnel.
When replacement parts and spares, as well as complete components, are required for existing non-safety-grade PORVs and block valves (and associated control systems), itis the intent ofthis generic letter that these items may be procured in accordance with the original construction codes and standards.
Requested Action 1.a:
FPL has verified that the PORVs and PORV block valves for both St. Lucie Units are classified as ASME Section IIIClass 1 valves, and are therefore included in the Florida Power and Light Quality Assurance Program for maintenance and procurement activities.
Requested Action 1.b:
FPL has verified that the maintenance/refurbishment programs for the PORVs and block valves which are currently in place at the St.
Lucie Plant are based upon the manufacturers'ecommendations.
As a result ofFPL's review of GL 90-06, additions to these programs which are beyond the manufacturers'ecommendations are underway, and willbe in place in accordance with the schedular requirements set forth in Generic Letter 90-06. Atthe present time, the end of the firstUnit 1 refueling outage which starts six months or later from the date of the Generic Letter is scheduled to be December, 1991; the first such outage on Unit 2 is scheduled to be
Florida Power and Light Generic Letter 90-06, Att. 1 Page 2 completed in June, 1992.
FPL has also verified that programs are in place to ensure that qualified plant and/or contract personnel are responsible for the implementation of these programs.
Requested Action 1.c:
FPL confirms its intention to use, at a minimum, the original construction codes and standards as outlined in Section IIIof the ASME Boiler and Pressure Vessel Code and in 10 CFR 50.55 (a) when procuring replacement parts and spares for existing PORVs and block valves.
Recommended Action 2 2.1.
Include PORVs, valves in PORV control air systems, and block valves within the scope of a program covered by Subsection IWV,"Inservice Testing of Valves in Nuclear Power Plants," of Section XIof the ASME Boiler and Pressure Vessel Code.
The PORVs and block valves on both St. Lucie Units are included within the St. Lucie Plant Pump and Valve Programs as a part of the plant Inservice Testing Program in accordance with ASME Section XISubsection IWV-1100.
2.2.
Stroke testing ofPORVs should only be performed during Mode 3 (HOT STANDBY)or Mode 4 (HOT SHUTDOWN) and in all cases prior to establishing conditions where the PORVs are used for low-temperature overpressure protection.
Stroke testing of the PORVs should not be performed during power operation.
The PORVs and block valves are tested in accordance with the guidance provided in ASME Section XISubsection IWV-1100 and the existing Technical Specification Surveillance Requirements.
Testing of these valves is performed under conditions which ensure the continued safe operation of the plant.
2.3 ITjhe PORV block valves should be included in the licensees'xpanded MOVtest program discussed in NRC Generic Letter 89-10, "Safety-Related Motor Operated Valve Testing and Surveillance," dated June 28, 1989.
Florida Power and Light Generic Letter 90-06, Att. i Page 3 FPL has verified that the PORV block valves have been included within the MOVtest program developed in response to Generic Letter 89-10, "Safety-Related Motor Operated Valve Testing and Surveillance."
Recommended Action 3:
For operating PWR plants, modify the limitingconditions of operation ofPORVs and block valves in the technical specifications for Modes 1, 2 and 3 to incorporate the position adopted by the staff in recent licensing actions.
Florida Power and Lightdoes not propose to incorporate the proposed Technical Specifications for Modes 1, 2 and 3 as recommended in the Generic Letter. The bases for this decision are discussed in Attachment 2 to this letter.
FLORIDAPOWER A&KLIGHT St. Lucie Units 1 and 2 hmn2 GENERIC LE<TTER 90-06 In Generic Letter 90-06, the staff stated that the role ofpower-operated relief valves (PORVs) has changed such that these valves are now relied upon by many Westinghouse, B&Wand CE designed plants to perform one, or more, of the following safety-related functions:
1.
Mtigation of a design-bases steam generator tube rupture accident, 2.
Low-temperature overpressure protection of the reactor vessel during startup and shutdown, or 3.
Plant cooldown in compliance with Branch Technical Position RSB 5-1 to SRP 5.4.7, "Residual Heat Removal System."
Florida Power and Light has evaluated each of the functions for applicability to the St. Lucie Plant.
The results of this evaluation are provided below.
Miti a' fa esi n-basissteam eneratortu ru tureaccident The emergency operating procedures (EOPs) in place at St. Lucie Units 1 and 2 adhere to the guidance provided in CEN-152, Revision 3. The strategy for the management of a steam generator tube rupture event is included in these guidelines.
A review of CEN-152, Revision 3, shows that depressurization of the reactor coolant system (RCS) followinga steam generator tube rupture event is accomplished using the pressurizer spray valves, the auxiliary spray valves, operation of the charging and letdown subsystem, or the throttling ofthe high pressure safety injection (HPSI) pumps (where applicable in accordance with specified HPSI throttling criteria). The use ofPORVs is not included in the Combustion
, Engineering accident management strategy as a means ofdepressurization of the RCS.
Areview ofthe plant-specific operating procedures which implement CEN-152, Revision 3, verifies that plant procedures followthe guidance promulgated in'CEN-152 and that PORVs are not credited as a possible success path for the depressurization of the reactor coolant system in a steam generator tube rupture event.
By letter dated August 2, 1988, the staff conditionally approved the use of CEN-152, Revision 3, for use as a guidance document for the preparation of emergency operating procedures for Combustion Engineering plants. As the St. Lucie Units'OPs followthe guidance provided by this document, FPL considers that the RCS depressurization function for the St. Lucie Units during a steam generator tube rupture event has been adequately addressed without crediting the use of PORVs, and that the staff has approved this strategy through its approval of CEN-152, Revision 3.
~
I I, ~
Florida Power and Light Gcncric Lcttcr 9046, Att.2 Page 2 Low-tern rature ove ressure rotection of the reactor vessel durin startu and shutdown Both St. Lucie Units credit the use ofPORVs for the mitigation ofa low-temperature overpressure (LTOP) event during Modes 4 through 5, when the reactor coolant system pressure boundary is intact. St. Lucie Unit 2 also credits the use of the residual heat removal (RHR) or shutdown cooling (SDC) safety reliefvalves forLTOP event mitigation when the shutdown cooling system is in service.
To ensure that the concerns raised by the staff in Generic Letter 90-06 are appropriately addressed, FPL is evaluating the potential reduction in the risk ofan LTOP event which is engendered by limitingthe allowed outage time for the PORVs as recommended in Enclosure B ofGL 90-06.
Completion of this evaluation is scheduled to support submittal of license amendment proposals in accordance with the schedule put forth in the generic letter. Atthe present time, the end ofthe first Unit 1 refueling outage which starts six months or later from the date of the Generic Letter is scheduled to be December, 1991; the first such outage on Unit 2 is scheduled to be completed in June, 1992. FPL willnotify the staff of the result of the evaluation upon its completion.
Plant cooldown in com liance with Branch Technical Position RSB 5-1 St. Lucie Unit 1 St. Lucie Unit 1 was not licensed in accordance with the requirements ofBranch Technical Position (BTP) RSB 5-1. However, FPL has demonstrated that the Unit may be placed on shutdown cooling through the use of the auxiliary spray system and the atmospheric dump valves.
Should the auxiliary spray system not be available, an alternate means ofcooldown is provided by utilizing a 'filland shrink'ethod ofcooling: the pressurizer is filledwith relatively cool water from the Boric Acid Makeup Tank (BAMT)or the Refueling Water Tank (RWT). The reactor coolant system is then cooled through the use of the atmospheric dump valves, and, as itcools, loses volume. When the pressurizer level falls to an appropriate point, the cooldown is stopped, and the pressurizer is again filledfrom the BAMTor the RWT, and the cooldown using the atmospheric dump valves is repeated.
This process is repeated until the shutdown cooling system entry window is attained.
't. Lucie Unit 2 St. Lucie Unit 2 was licensed as a Class 2 plant in accordance with the provisions ofBranch Technical Position RSB 5-1. The Safety Evaluation Report issued by the staff forUnit2 (NUREG 0843, dated October, 1981) specifically documents compliance with this position.
The systems which are used to cool the unit down to shutdown cooling entry conditions are the auxiliary feedwater system, the main steam system, the chemical and volume control system, the component cooling water system and the shutdown cooling system.
Assuming the loss ofoffsite power, the most limitingsingle failure associated with cooldown is the failure of a dc bus and associated diesel generator.
Three possible methods are available for the depressurization of the primary plant in this event; use of the PORVs is referenced as one of these methods.
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Florida Power and Light Generic Letter 90-06 Att. 2 Page 3 Review of otential safet -related functions ofPORVs FPL does not concur that the PORVs should be considered as performing a safety-related function.
Section 3.2.2 of the St. Lucie Unit 1 and the St. Lucie Unit2 Updated Final Safety Analysis Reports (UFSARs)provide the followingdefinition of a safety system:
A safety system... is any system that functions to shut down the reactor, cool the core or cool another safety system or the containment, and contains, controls, or reduces radioactivity released in an accident.
The PORVs do not meet this definition, based upon the following; PORV functioning does not provide any means ofreactivity control, therefore these components cannot provide any means of shutting down the reactor.
2.
3.
The PORVs are relief valves, and therefore do not function to provide any cooling to the core or any other safety system, or to the containment.
As the PORVs are relief valves, and such components cannot, by design, contain any of the radioactivity released in an accident, nor can they control such radioactivity. Additionally, the PORVs do not serve any radiological function, therefore these valves cannot reduce a potential radioactivity release by their functioning.
Therefore, FPL does not propose to modify the limitingconditions of operation ofPORVs or block valves in the St. Lucie Unit 1 or Unit 2 Technical Specifications for Modes 1, 2 and 3 to incorporate the position adopted by the staff in recent licensing actions for the followingreasons:
1.,
these components are not credited for the mitigation of a steam generator tube rupture event for either St. Lucie unit, 2.
sufficient redundancy is available to ensure that the requirements ofBTP RSB 5-1 are met, and PORVs do not meet the definition of a safety-related system as defined in the St.
Lucie Units 1 and 2 UFSARs.