ML17241A415
| ML17241A415 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 07/22/1999 |
| From: | Stall J FLORIDA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| L-99-159, NUDOCS 9907270177 | |
| Download: ML17241A415 (30) | |
Text
CATEGORY REGULAT RY INFORMATION DISTRIBUTIO SYSTEM (RIDS)
ACCESSION NBR:9907270177 DOC.DATE: 99/07/22 NOTARIZED: NO DOCKET ¹ FACIL:50-389 St. Lucie Plant, Unit 2, Florida Power & Light Co. 05000389 APZH.NAME STALL,'.J.A'.
RECIP.NAME
'lorida
" AUTHOR AFFILIATION Power &. Light Co.
RECIPIENT AFFILIATION Records Management Branch (Document Control Desk)
SUBJECT:
Forwards revised Relief Request 25 for second 10-yr ISI interval for Unit'.
DISTRIBUTION CODE: A047D COPIES RECEIVED:LTR. ENCL SIZE:
TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code NOTES:
E RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL LPD2-2 LA 1 1 GLEAVES,W 1 1 0
INTERNAL: ACRS 1 1 FILE CENTER 0 1 NUDOCS-ABSTRACT 1 1 OGC RP 1 0 RES/DET/ERAB 1 1 RES/DET/MEB 1 1 EXTERNAL: LITCO ANDERSON 1 1 NOAC 1 .1 NRC PDR 1 1 D
0
'E P ~~<Etl%);)S NOTE TO ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE."TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATIONi CONTACT THE DOCUMENT DOCUM CONTROL DESK (DCD) ON EXTENSION 415-2083 TOTAL NUMBER OF COPIES REQUIRED: LTTR 11 ENCL 10
Florida Power 5 Light Company, 6351 S. Ocean Drive, Jensen Beach, FL 34957
'PL, Zuly 22, 1999 L-99-159 10 CFR 50.55a 10 CFR 50.4 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 St. Lucie Unit 2 Docket No. 50-389 Second Ten-Year In-Service Inspection Interval Revised Relief R uest 25 The second ten-year in-service inspection (ISI) interval for St. Lucie Unit 2 began on August 8, 1993. Florida Power & Light Company (FPL) submitted the ISI program relief request (R/R) 25 by letter I 99-78 on April 5, 1999. R/R 25 proposes to use, the alternative icquiicments of ASME Code Case N-613 in lieu of the requirements of ASME Section XI Figures IWB-2500-7(a) and IWB-2500-7(b). In addition, the R/R proposes to use this Code Case in lieu of the requirements of ASME Section V, Article 4 for the performance of the required volumetric examinations as specified in Table IWB-2500-1 Category B-D of the 1989 Edition of ASME Section XI. FPL has determined pursuant to 10 CFR 50.55a(a)(3) that the proposed alternatives would provide an acceptable level of quality and safety, and that compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. In a telephone conference on June 16, 1999, the NRC stated that additional information was required to complete the safety evaluation for this R/R.
The purpose of this letter is to supplement R/R 25 with the information requested by the NRC.
Please contact us should you require any additional clarifications.
Very truly yours, J. A. Stall Site Vice President St. Lucie Plant Enclosure cc: Regional Administrator, USNRC, Region II p4 Senior Resident Inspector, USNRC, St. Lucie Plant 9907270i77 990722 8'P PDR')>ADQCK 05000$
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Gt. Lucie Unit 2 Docket No. 50-389 L-99-159 Attachment Page t
1 St. Lucie Unit 2 SECOND INSPECTION INTERVAL RELIEF REQUEST NUMBER 25 A. COMPONENT IDENTIFICATION'lass:
1 Reactor Pressure Vessel Pressure-retaining Nozzle-to-Vessel welds examined at St. Lucie Unit 2.
B. EXAMINATIONREQUIREMENT:
Rules for Inseivice Inspection of Nuclear Power Plant Components,Section XI, 1989 Edition, Examination Category B-D Full Penetration Welds of Nozzles in Vessels. Code Item B3.90, Figure IWB-2500-7 (a) 8 (b).
ASME Section V, 1989 Edition, Article 4, Paragraphs; T-441.3.2.5 Angle Beam Scanning, T-3.2.6 Scanning for Reflectors Oriented Parallel to the Weld, and T-441.3.2.7 Scanning for Reflectors Oriented Transverse to the Weld.
C. RELIEF REQUESTED'ursuant to 10 CFR 50.55a (a)(3), FPL requests to use the alternative requirements of Code Case N-613 in lieu of the requirements of ASME Section XI Figures IWB-2500-7 (a) and IWB-2500-7 (b).
We also request to use this Code Case in lieu of the requirements of ASME Section V, Article 4 for the performance of the required volumetric examinations as speciTied in Table IWB-2500-1 Category B-D of the 1989 Edition of ASME Section XI. These examinations will be performed during the second inspection interval.
D. BASIS FOR RELIEF:
FPL is currently required to perform in-service examinations of selected welds in accordance with the requirements of 10 CFR 50.55a, plant technical specifications, and the 1989 Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, Rules for In-Service Inspection of Nuclear Power Plant Components. This Code edition invokes the examination volume requirements of Figures IWB-2500-7 (a) and IWB-2500-7 (b). This Code edition also invokes the examination requirements of Appendix I, Article 1-2000 which reference ASME Section V, Article 4 that essentially prescribes twenty (20) year old examination methodology. FPL will perform the required examinations using the methodology of Code Case N-622 as presented in Relief Request ¹22. This will provide added assurance that the Reactor Vessel welds have remained free of service related flaws thus enhancing quality and ensuring plant safety and reliability.
The examination volume for the Reactor Vessel pressure retaining nozzle-to-vessel welds extend far beyond the weld into the base metal, and is unnecessarily large. This extends the examination time significantly, and results in no net increase in safety, as the area being examined is a base metal region which is not prone to in-service cracking and has been extensively examined before the vessel was put into service and during the First Inseivice examination.
The implementation of Code Case N-613 is also expected to reduce on-vessel examination time by as much as 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, which translates to significant cost savings and reduced personnel radiation exposure.
St. Lucie Unit 2 Docket No. 50-389 L-99-159 Attachment Page 2 St. Lucie Unit 2 SECOND INSPECTION INTERVAL RELIEF REQUEST NUMBER 25 E. ALTERNATIVEEXAMINATIONS:
- 1) Perform examinations in accordance viith Code Case N-613
- 2) Perform examinations in accordance with Code Case N-622 (Relief Request No. 22).
- 3) Periodic system pressure tests per Category B-P, Table IWB-2500-1 F. IMPLEMENTATIONSCHEDULE:
Second In-Service Inspection Interval G. ATTACHMENTS TO THE RELIEF:
0 CASE CASES OF ASME BOILER AND PRESSURE VESSEL CODE Approval Oata: July 3Q, 1SS&
See Numeric index for expiration end en Y reeffirmetlon dates.
Case N-613 Ultrasonic Examination of Full Penetration Nozzles in Vessels, Examination Category B-D, Item No's. B3.10 and B3.90, Reactor Vessel-To-Nozzle Welds, Fig. IWB-2500-7(a), (b), and (c)
Section XI, Division 1 Inquiry: What alternatives to the examination re-quirements of Section XI, Appendix I and Section V, Article 4 are permissible when performing ultrasonic examination of reactor vessel-to-nozzle weldsq Reply: It is the opinion of thc Committee that ultra-sonic examination of Category B-D nozzles may be conducted using techniques designed for detection and sizing of surface and subsurface flaws within the ex-amination volume (A-B-C-D-E-F-G-H), oriented in a plane normal to the vessel inside surface and parallel to the weld for Figs. 1 and 2, and oriented in a plane normal to the nozzle inside surface and parallel to thc weld for Fig. 3.
1051 SUPP. 2 NC
GAsE (continuad)
N-613 CASES OF ASME BOILER AND PRESSURE VESSEL CODE tn1
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rntg ma ~ nozzle wall thickness rs ~ shell lorhead) thickness rf nozzle inside corner radius B
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Corner flaw EXAMINATIONREGION INote l1) I EXAMINATIONVOLUME INote I2) I Shell lor head) adjoining region C-D<<E-F Attachment weld region B-C-F-G Nozzle cylinder region A-B-G-H Nozzle Inside corner region M-N-0-P NOTES'1)
Examination regions are identified for the purpose of differentiating the acceptance standards in IWB.3512.
, l2) Examination volumes may be determined either by direct measurements on the component or by measurements based on design drawings.
FlG, 1 NOZZLE IN SHELL OR HEAD (Exantlnation Zones in Barrel Type Nozzles Joined by Full Penetration Corner Welds)
SUPP. 2 NC 1052
CASE (continued)
N-613 CASES OF'SME BOILER AND PRESSURE VESSEL CODE rt. rz ~ nottle wall thickness ts a shell (or head) thickness rf ~ nottie inside corner radius 0 A B C D I
I I
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Corner flaw EXAMINATIONAEGION Note (1)l EXAMINATIONVOLUME INote (2))
Shell {or head) adjoining region C-D-E-F Anachment weld region 8-C-F-G Noulo cylinder region A-B-G-H Noztfe inside corner region M-N-0-P NOTES:
(1) Examination regions are identified for the pur pose of differentiating the acceptance standards ln IWB.3512.
'2) Examination volumes may be determined either by direct measurements on the component or by measurements based on design drawings.
FIG. 2 NOZZLE IN SHELL OR HEAD (Examination Zones in Flange Type Nozzles Joined by Full Penetration Butt Welds) 1053 SUPP. 2 NC
CASE (contint)ed)
H-613 CASES OF ASME BOILER AND PRESSURE VESSEL CODE II I II I II I II I II I II r%
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II rt ~ nozzlewatlthickness tnt I, ~ shell {or head) thickness r; ~ nonte inside corner radius 1I, {n
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I // A-8-C-D-E-F-G-H M r Corner naw EXAM)NAT)ONREGlON INote Il)I EXAMINATIONVOLUME {Note {2)I Shell {or head) adjoining region C-D-E-F-G Auachment weld region 8-C-G Noule cylinder region A-8-G-H Non)a inside corner region M-N-0-P NOTES:
{1) Examination regions are identified for the purpose of differentiating the acceptance standards ln Iyya 35)2.
{2) Examination volumes may be determined either by direct measurements on the component or by measurements based on design drawings.
FIG. 3 NOZZLE IN SHELL OR HEAD (Exatnination Zones in Set-On Type No22les Joined by Full Penetration Corner Welds)
SUPP.2- NC I054
Distri72.txt Distribution Sheet Priority: Normal From: Stefanie Fountain Action Recipients: Copies:
K Jabbour 1 Paper Copy B Clayton 1 Paper Copy Internal Recipients:
RidsRgn2MailCenter 0 OK Rids Res DetMeb 0 OK Rids Res DetErab 0 OK RidsOgcRp 0 OK RidsManager 0 OK RES/DET/MEB 1 Paper Copy RES/DET/ERA B 1 Paper Copy OGC/RP 1 Paper Copy CE (MlT 1 1 Paper Copy ACRS Paper Copy External Recipients:
NOAC Paper Copy INEEL Marshall Paper Copy Total Copies: 9 Item: ADAMS Document Library:- ML ADAMS"HQNTAD01 ID: 003691671:1
Subject:
St. Lucie Unit 2 lnservice Inspection Plan, Second Ten-Year Interval Relief Request 27.
Body:
ADAMS DISTRIBUTION NOTIFICATION.
Electronic Recipients can RIGHT CLICK and OPEN the first Attachment to View the Document in ADAMS. The Document may also be viewed by searching for Accession Number ML003691671.
Page 1
Distri72.txt A047 - OR Submittal: Inservice/Testing/Relief from ASME Code Docket: 05000389 Page 2
FlarIda Power 5 Light Company, 6351 S. Ocean Drive. Jensen Beach, FL 34957 March 6, 2000 L-2000-59 10 CFR 5024 10 CFR 50.55a U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re: St. Lucie Unit 2 Docket No. 50-389 Inservice Inspection Plan Second Ten- Year Interval
~22 2 22 Pursuant to 10 CFR 50.55a(a)(3), Florida Power & Light Company (FPL) requests approval of Relief Request (R/R) 27, Reactor Vessel 1Vuts. FPL has determined pursuant to 10.CFR 50.55a(a)(3)(i) that the proposed alternatives would provide an acceptable level of quality and safety.
The relief request proposes an alternative to the Code required surface examinations of the reactor pressure vessel (RPV) closure head nuts as specified in Table IWB-2500-1 of the 1989 edition of ASME Section XI. In lieu of the Code requirements, FPL willperform a visual VT-1 on the RPV closure head nuts. The IWB-3517 acceptance criteria of the 1989 edition of Section XI will be used for evaluation of indications. This request for relief is identical to St. Lucie Unit 1, Third Ten-Year Interval, R/R 9 that was approved by NRC safety evaluation (TAC NO. MA0965) dated June 18, 1999.
Approval is requested by February 28, 2001 to support the fall 2001 St. Lucie Unit 2 refueling outage (SL2-13). Please contact us if there are any questions about this submittal.
Very truly yours, Rajiv S. Kundalkar Vice President St. Lucie Plant RSK/GRM Attachment cc: Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant
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St. lucio Unit 2 Docket No. 50-389 L-2000-59 Attachment Page 1 l St. Lucie Unit 2 SECOND INSPECTION INTERVAL RELIEF REQUEST NUMBER 27 A. COMPONENT IDENTIFICATION:
Class: 1 Reactor Pressure Vessel Nuts B. EXAMINATIONREQUIREMENT:
Rules for Inservice Inspection of Nuclear Power Plant Components,Section XI, 1989 Edition
- -:: Exam,."...'::.-"",,'I 'tem':no.'-;..-'-.:";:":.::,.-.;.-:','-:'=.:'::Examin'ation Require'm'ents,.",,",,"".,-.',';::,':,,"'.::",'-,.,,:',",',",",,,",':': ',"i ':.',,":,'.":-:,",~!-'.,',";-:~.',
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B-G-1 B6.10 Essentially 100% surface examination of entire surface of closure head nuts C. RELIEF REQUESTED:
Pursuant to 10 CFR 50.55a (a)(3)(i), FPL requests an alternative to the Code required surface examinations of the reactor pressure vessel closure head nuts as specified in Table IWB-2500-1 of the 1989 Edition of ASME Section XI.
D. BASIS FOR RELIEF:
The reactor pressure vessel closure head nut configuration is such that only the outside surface is readily accessible for surface examination. The threaded area on the inside of the nuts is very diflicult to adequately clean for both liquid penetrant and magnetic particle examination. The cleaning and preparation of the nuts for surface preparation could result in additional damage. Pooling of penetrant and magnetic particle material at the bottom of the nut (which must be placed on its side for examination) could mean additional cleaning time for proper examination of this area. This additional examination may further damage the nuts due to handling.
The 1989 Edition of Section XI does not provide acceptance criteria for Code Category B-G-1 surface flaws found during the examinations. FPL has used engineering evaluations on every indication noted in order to determine whether a nut is acceptable for continued service. This results in more costs and handling (with the possibility of more damage) of the nuts as the engineers determine whether an indication is acceptable.
Beginning in the 1989 Addenda of ASME Section XI, the examination requirement for RPV closure head nuts was changed from surface to visual VT-1. In addition, the acceptance standards of IWB-3517 were adopted, which is the same standard as for Code Category B-G-2 bolting. A review of later Codes and Addenda shows this examination technique and acceptance standard has not changed.
Conditions that require corrective measures prior to placing the RPV Closure head nuts back in service include corrosion, damaged threads, or deformation. Surface examinations are qualified for the detection of linear indications, and surface examination acceptance criteria mention only rejectable linear flaw lengths. The 1989 Code does not provide any acceptance criteria for linear indications found during surface examination of RPV closure head nuts, because the acceptance criteria were still being developed at the time the Code edition was published.
0 St. Lucie Unit 2 Docket No. 50-389
~ i I 2000-59 Attachment Page 2 St. Lucie Unit 2 SECOND INSPECTION INTERVAL RELIEF REQUEST NUMBER 27 By using the IWB-3517 acceptance cnteria, FPL would have definite rules that could be followed for evaluation of indications found during examinations. The indications would be compared against published standards.
Footnote 3 of IWB-3517 clearly states that only relevant conditions must be evaluated. This would preclude scratches, fabrication marks, roughness, etc. from being recorded (except as a general condition). These types of indications are often seen during surface examination, and may be considered non-relevant, which requires the areas in question to be cleaned and re-examined.
VT-1 visual examination acceptance criteria include requirements for evaluation of crack-like indications and other relevant conditions requiring corrective action, such as deformed or sheared threads, localized corrosion, deformation of part, and other degradation mechanisms. Therefore, it can be concluded that the VT-1 visual examination provides a more comprehensive assessment of the condition of the closure head nut than a surface examination. By performing a visual VT-1 examination of the RPV closure head nuts, an acceptable level of quality and safety is provided.
This request for relief is identical to St. Lucie Unit 1 Third Ten-Year Interval Relief Request 9 that was approved by NRC safety evaluation dated June 18, 1999.
E. ALTERNATIVEEXAMINATIONS:
FPL will perform a visual VT-1 on the RPV Closure Head Nuts. The IWB4517 acceptance criteria of the 1989 Edition of Section XI will be used for evaluation of indications.
F. IMPLEMENTATIONSCHEDULE:
Second Inservice Inspection Interval G. ATTACHMENTS TO THE RELIEF'one
Distri42.txt Distribution Sheet Priority: Normal From: Elaine Walker Action Recipients: Copies:
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Rids Res DraaOerab OK Rids Res DetErab 'I OK RidsNrrDssaSplb OK RidsNrrDripRexb OK RidsNrrDipmlolb 1 OK
. RidsManager OK RGN 2 FILE 01 Not Found RES/DRAA/OERAB Not Found RES/DET/ERAB 1 Not Found NRR/DSSA/SPLB Not Found NRR/DRIP/REXB 1 Not Found NRR/DIPM 1 Not Found E CENTE. Not Found ACRS Not Found External Recipients:
NRC PDR Not Found NOAC QUEENER,DS Not Found NOAC POORE,W. Not Found L ST LOBBY WARD Not Found internet: smittw@inel.gov Not Found INEEL Marshall Not Found Total Copies: 22 Item: ADAMS Document Library: ML ADAMS"HQNTAD01 ID: 003672905
Subject:
Reportable occurence regarding the Unit 2 exceedance of its maximum licensed power I Page 1
Distri42.txt evel of 2700 megawatts thermal by approximately 0.4% rated thermal power on 12/13/99.'ody:
PDR ADOCK 05000389 S Docket: 05000389, Notes: NIA Page 2
Florida Power 5 Light Company, 6351 S. Ocean Drive, Jensen Beach. FL 34957 December 27, 1999 L-99-277 10 CFR 50.4 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE: St. Lucie Unit 2 Docket No. 50-389 Follow-up Report License Condition 2.F This letter provides the Florida Power and Light Company'(FPL) written follow-up report due within 14 days of St. Lucie Unit 2 exceeding the License Condition 2.C. (1) Maximum Power Level. This report is required by St. Lucie Unit 2 Operating License Condition 2.F. During the morning of December 13, 1999, St. Lucie Unit 2 exceeded its maximum licensed power level of 2700 megawatts thermal (MW, ) by approximately 0.4% rated thermal power (approximately 11.2 MWg. The maximum actual power was calculated to be 100.413% of rated thermal power. During the period of time that power exceeded 100%, the maximum indicated power by the plant computer (DDPS) calorimetric log was 99.87% rated thermal power.
The St, Lucie Unit 2 steam generator blowdown system was removed from service and isolated for maintenance between 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> and 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br /> on December 12, 1999. When blowdown flow was decreased to zero, indicated power also decreased, as was expected. Accordingly, the licensed control room operators increased indicated power to 100%. The plant computer (DDPS) calorimetric log for blowdown at 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br /> indicated essentially zero, as did the blowdown flow-indicating controller. At 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> on December 13, 1999, while recording performance data, a FPL system engineer noted that the indicated feed flow was higher than normal for 100% power. On further inspection, it was noted that indicated flow on the blowdown controllers was zero but the DDPS calorimetric log was indicating a total of 50,000 ibm/hr blowdown flow. The erroneously high blowdown flow input to the calorimetric caused indicated DDPS core power to be lower than actual core power. The system engineer informed the assistant nuclear plant supervisor (ANPS) (Unit 2 control room senior reactor operator (SRO)) and the nuclear plant supervisor (NPS) (shift supervisor SRO). Reactor power was reduced by approximately 0.5% and the blowdown flow transmitters to the DDPS were vented. On the venting of the flow transmitters, the DDPS-indicated blowdown flow returned to essentially zero. FPL instrumentation and control g&C) personnel indicated that the transmitters appeared to be under a vacuum, which produced the erroneous blowdown flowrate.
oa 3L,) ZggiW an FPL Group company
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S St. Lucie Unit 2 Docket No. 50-389 L-99-277 Page 2 Initial review of the DDPS data by FPL indicates that the hourly average power level exceeded 100% by approximately 0.4%. This exceeded the licensed maximum power of the Unit 2 Operating License Condition 2.C. (1). In accordance with License Condition 2.F. of the Operating License, this was reported to the NRC Regional Administrator's designee (L. Wert, NRC Region Il) on December 13, 1999, and followed by facsimile. The event has been entered into the plant's corrective action program (Condition Report (CR) 99-2488). The root cause will be determined and long-term corrective actions identified in accordance with the corrective action program.
Please contact us ifthere are any questions about this submittal.
V truly yours, A. 1 Vice President St. Lucie Plant JAS/GRM cc: Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant
Distri46.txt Distribution Sheet Priority: Normal From: Elaine Walker Action Recipients: Copies:
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RidsResDraaOerab OK RidsResDetErab OK RidsNrrDssaSplb OK RidsNrrDripRexb OK RidsNrrDipmlolb OK Rids Manager .OK RGN2 FILE 01 Not Found RES/DRAA/OERAB Not Found RES/DET/ERAB 1 Not Found NRR/DSSA/SPLB, 1 Not Found NRR/DRIP/REXB 1 Not Found NRR/D 1 Not Found CE TER 1 Not Found CRS Not Found External Recipients:
NRC PDR Not Found NOAC QUEENER,DS Not Found NOAC POORE,W. 1 Not Found L ST LOBBY WARD 1 Not Found internet: smittw@inel.gov 1 Not'Found INEEL Marshall Not Found Total Copies:
Item: ADAMS Document Library: ML ADAMS"HQNTAD01 ID: 003671120
Subject:
Letter informing NRC of change in commitment made in letter dated 10/17/1997 re root c Page 1
(i Distri46.txt ause analysis on the failed RVLMS probe once it was removed during the fall 1998 refue ling outage.
Body:
PDR ADOCK 05000389 S Docket: 05000389, Notes: N/A Page 2
Florida Power & Light Company, 6351 S. Ocean Drive, Jensen Beach, FL 34957 L-99-275 10 CFR 50.4 10 CFR 50.36 DEC 2 2 1999 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re: St. Lucie Unit 2 Docket No. 50-389 Chan e in Commitment Ref: FPL Letter L-97-264 dated October 17, 1997. Subject - Technical Specification Special Report for Failure of Channel B of the Reactor Vessel Level Monitoring System (RVLMS) on September 21, 1997.
In the referenced letter, Florida Power 8 Light Company (FPL) submitted a Special Report pursuant to the requirements of Technical Specification 3.3.3.6, Action c, and Technical Specification 6.9.2 concerning the failure of the reactor vessel level monitoring system (RVLMS) channel B probe. Investigation revealed low resistance to ground measurements on multiple cable inputs from the channel B RVLMS probe. The cause of the failure could not be determined with the reactor at power because further assessment of the probe assembly and cable connections inside containment was precluded due to high radiation in the area of the probe and cable connections. FPL committed to perform a root cause analysis on the failed RVLMS probe once it was removed during the fall 1998 refueling outage.
During the outage that occurred in late 1998, the connections and cabling to the probe were tested and ruled out as the cause of the failure. The failure appeared to be within the actual probe. The RVLMS probe was replaced and the failed probe was believed to have been transferred to the spent fuel pool. Because of the dose involved with handling the probe and the potential for generation of highly radioactive contamination, a decision was made that a procedure would be required for disassembly and inspection of the failed probe. The root cause evaluation was to be performed as warranty work by a combined team of the supplier and the subcontracted manufacturer.
The procedure was completed in late April 1999 and reviewed during May 1999.
Based on availability of the appropriate experts for the investigation, a tentative start date in September 1999 was established for performing the root cause effort. In preparation of their arrival, Engineering determined that the probe could not be located and it is believed that the probe had been disposed of as part of an overall effort to clean up the spent fuel pool.
an FPL Group company
+~n C r +
St. Lucie Unit 2 L-99-275 Docket No. 50-389 Page 2 Chan e in Commitment In June 1999, the Health Physics (HP) department had initiated a project to remove longstanding irradiated components from the Unit 1 and 2 spent fuel pools. The scope and schedule for the clean up project had been communicated to all levels of the plant organization and progress was being tracked on the daily plan of the day. However, a detailed listing of the components being removed was not published.
An investigation determined that a personnel error was made during the initial RVLMS probe root cause planning activities in that positive means for controlling the disposition of the probe were not developed. The inadequate communication between Engineering, IRC Maintenance, the contracted reactor crew, and HP led to the inadvertent discarding of the failed probe when St. Lucie removed stored high radiation material from the spent fuel pools. A contributing cause was the multiple accountability transfers that occurred from the time the problem was first identified until the probe was actually dismantled and shipped as waste.
In response to the inadvertent disposal of the RVLMS probe, St. Lucie has revised procedures ADM-08.04, "Root Cause Evaluations," and ADM-20.01, "Event Response Team," to ensure that items identified for root cause investigations are properly tracked and maintained such that they will not be inadvertently discarded. HP is developing a procedure to establish requirements governing control and storage of materials to be stored in the spent fuel pools. This procedure will be implemented by the end of January 2000..
To address the generic implications of this event, FPL conducted a review of industry historical data on liquid level probes. The liquid level probe has been a standard replacement for the heated junction thermocouple at St. Lucie and within the industry for about eight years. It was originally provided with an eight-pin connector and then was offered with a 40-pin connector in 1993. The 40-pin connector probe was first installed Unit 1 in 1996 and Unit 2 in 1997. To date, only one other probe with the 40-pin configuration has been identified as a premature failure. This failed probe is currently installed at the Braidwood Station/Commonwealth Edison Company. The Braidwood liquid level probe is scheduled for replacement during the next scheduled refueling outage in the spring of 2000. ABB/CE has contacted Braidwood to coordinate an analysis for their failed liquid level probe. Additionally, ABB/CE has agreed to communicate the outcome of the root cause analysis with Florida Power and Light. The information from Braidwood is expected to provide insight into the failure at St. Lucie.
St.l ucie Unit 2 L-99-275 Docket No. 50-389 Page 3 Chan e in Commitment Please contact us if there are any questions regarding this letter.
Very truly yours, Thomas. F. Plunkett President Nuclear Division Florida Power 8 Light TFP/JAS/E JW/KWF cc: Luis A. Reyes, Regional Administrator, USNRC Region II Senior Resident Inspector, USNRC, St. Lucie Plant