ML17229A550

LER 97-008-00:on 971107,inadequate CR Ventilation Surveillance Resulted in Condition Prohibited by Ts.Caused by non-cognitive Personnel Error.Operating Procedure 2-1900050 Was revised.W/971205 Ltr

ML17229A550
Person / Time
Site:	Saint Lucie
Issue date:	12/05/1997
From:	Frehafer K, Stall J FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-97-303, LER-97-008-02, LER-97-8-2, NUDOCS 9712110174
Download: ML17229A550 (8)

Text

REGULA Y INFORMATION DXSTRIBUTIWSYSTEM (RIDS)

ACCESSION NBR: 9712110174 DOC.DATE: 97/12/05 NOTARIZED: NO DOCKET FACIL:50-389 St. Lucie Plant, Unit 2, Florida Power S Light Co. 05000389 AUTQy NAME AUTHOR AFFILIATION FREHAFER,K.W. Florida Power 6 Light Co.

STALL,J.A. Florida Power & Light Co.

RECXP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER'7-008-00:on 971107,inadequate CR ventilation surveillance resulted in condition prohibited by TS.Caused by non-cognitive personnel error. Operating Procedure 2-1900050 was revised.W/971205 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPXES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-3 PD 1 1 WIENSiL. 1 1 INTERNAL: ACRS 1 1 2 2 AEOD/SPD/RRAB 1 ' FILE CENTE 1 1 NRR/DE/ECGB 1 1 EELB 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HXCB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRZB 1 1 RES/DET/EIB 1 1 RGN2 FILE 01 1 1 EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE,J H 1 1 NOAC POORE,W. 1 1 NOAC QUEENER,DS 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, DISTRIBUTION LIST CONTACT THE DOCUMENT CONTRO DESK (DCD) ON EXTENSION 415-2083 FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 25 ENCL 25

Florida Power Ec Light Company, 6351 S. Ocean Drive, Jensen Beach, FL 34957 December 5, 1997 FPL L-97-303 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Re: St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 97-008-0 Date of Event: November 7, 1997 Inadequate Control Room Ventilation Procedure Results pecifications The attached Licensee Event Report is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Very truly yours, J. A. Stall Vice President St. Lucie Plant JAS/KWF Attachment cc: Regional Administrator, USNRC Region II Senior Resident Inspector, USNRC, St. Lucie Plant VT12i iOiT4 97%205 PDR ADOCK 05000889 8 PDR an FPL Group company

~ 'PPROVED BY OMB NO. 3160%104 NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (4-55) EXPIRES 04r30/ss ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATO INFORMATION COLLECTION REQUEST: 60.0 HRS. REPORTED LESSON LEARNED ARE INCORPORATED INTO THE UCENSING PROCESS AND FE BACK TO INDUSTRY. FORWARD COMMENTS REGARDING BURDEN ESTIMAT LICENSEE EVENT REPORT (LER TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (T.e F33)

UB. NUCLEAR REGUlATORY COMMISSION, WASHINGTON, DC 206660001 AND TO THE PAPERWORK REDUCTION PROJECT (3160<104), OFRCE 0 (See reverse for required number of MANAGEMENTAND BUDGET, WASHINGTON, DC 20603.

digits/characters for each bIockl FACIUTY NAME (1) DOCKET NUMBER (2) PAGE (3)

ST LUCIE UNIT 2 05000389 1 OF 5 TITLE (4)

Inadequate Control Room Ventilation Surveillance Results in Condition Prohibited by Technical Specifications FACIUTY NAME DOCKETNUMBER MONTH DAY SEQUENTIAL REVISION MONTH NUMBER NUMBER DAY YEAR N/A 05000 FACIUTY NAME DOCKET NUMBER 11 7 97 97 008 0 12 5 97 05000 OPERATING MODE (9) 20. 2201 (b) 20.2203(a) (2) (v) 50.73(e) (2) (i) 50.73(a)(2)(viii)

POWER LEVEL (10) 100 20. 2203 (a) (2) (i) 20.2203(a)(3)(ii) 50.73(a) (2) (iii) 73.71 OTHER 20.2203 (a) (2) (iii) 50.36(c) (1) 50.73(a) (2) (v) Specify in Abstract below or ln NRC Form 366A 20.2203(a) (2)(iv) 50.36(c) (2) 50.73(a) (2) (vii)

NAME TELEPHONE NUMBER Eno(ude Ares Code)

K. W. Frehafer, Licensing Engineer (561) 468-4284 CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE REPORTABLE TO NPRDS CAUSE SYSTEM COMPONENT MANUFACTURER TO NPRDS D VI N/A N/A N/A MONTH DAY YEAR EXPECTED YES SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE). X No DATE (15)

ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

On November 7, 1997, St. Lucie Unit 2 was in Mode 1 at 100 percent reactor power. Utility personnel identified a concern with an 18 month control room Technical Specification surveillance procedure while reviewing HVAC surveillance procedures to ensure that the intent of the Technical Specification surveillance requirements were being met. The surveillance procedure did not adequately test control room pressurization on an individual train basis. Operations declared both trains of the Control Room Emergency Cleanup System out of service and entered the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Technical Specification 3.7.7 ACTION statement.

Both trains of the Control Room Emergency Cleanup System were satisfactorily tested to the new test procedure on November 8, 1997, and the ACTION statement was exited.

The cause for the Unit 2 Control Room Emergency Cleanup System surveillance procedure deficiency was non-cognitive personnel error that occurred at the time of plant licensing during the development of the surveillance procedure. Corrective actions included 1) revising the surveillance procedure to provide for train specific testing, and 2) Other HVAC system Technical Specification surveillance procedures were reviewed for adequacy, with no additional issues identified.

NRC FORM 366 (4-B5)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIO I4-SSI LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST: LUCIE UNIT 2 05000389 2 OF 5 97 008 0 TEXT (if more speceis required, uso edditionel copies of NRC &rm 366AJ I17I On November 7, 1997, St. Lucie Unit 2 was in Mode 1 at 100 percent reactor power. As a result of a previous issue identified with HVAC Technical Specification (TS) surveillance procedures, utility personnel were reviewing HVAC surveillance procedures to ensure that the intent of the TS surveillance requirements were being met. This review identified a concern with the 18 month control room TS surveillance procedure that tests the pressurization of the control room emergency envelope. The issue was the surveillance procedure did not adequately test control room pressurization on an individual train basis.

Operations declared both trains of the Control Room Emergency Cleanup System (CRECS) [EIIS:Vl] out of service and entered the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> TS 3.7.7 action statement.

The surveillance testing method did not adequately ensure that each individual train of the CRECS was capable of meeting its design requirements with respect to the capability of the system to maintain at least a 1/8" water gage (w.g.) positive pressure while limiting Outside Air Intake (OAI) to s450 cfm. The Unit 2 CRECS is designed as a two train system capable of withstanding a single active failure coincident with a loss of offsite power. TS surveillance 4.7.7.e.3 requires a verification that the system maintains a 1/8" w.g. positive pressure relative to outside atmosphere with c450 cfm outside air intake. This su'rveillance is performed via Operating Procedure 2-1900050, "Control Room Pressure Periodic Test."

The existing test procedure did the following:

1) allows the use of either supply fan HVE-13A or HVE-13B;

2) closes both toilet exhaust valves (FCV-25-18 and FCV-25-19);

3) closes both kitchen exhaust valves (FCV-25-24 and FCV-25-25); and

4) allows the use of either the north or south outside air intake valves.

The intent of the surveillance is to demonstrate that control room integrity is sufficient to maintain a 1/8" w.g. positive pressure with not more than 450 cfm of filtered outside air makeup in order to protect against unfiltered air in-leakage.

Control room integrity is a function of both the leak-tightness of the control room envelope and the capability of the ventilation system to provide the necessary makeup air to pressurize the control room envelope. To this extent, the use of either the -13A fan or -13B fan is immaterial since each fan train is separately tested to ensure proper system filtration and flow capabilities; however, there are train-related aspects to both the ability to establish control room integrity and the ability to control the amount of OAI.

The kitchen and toilet exhaust lines are each provided with two isolation valves, as noted above. One of.

these two valves is powered from train A and the other from train B. By testing with both valves in the closed position, the ability of a single valve to provide sufficient isolation (i.e., to establish integrity of the control room envelope) is not assured. The possibility exists that one of the two valves does not provide adequate isolation capabilities such that it may represent a threat to control room integrity in the event of a failure of the opposite valve.

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIO I4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST. LUCIE UNIT 2 05000389 3 OF 5 97 008 0 TEXT flfmore spece is required, use edditionel copies of NRC Form 386AJ I 17I Similarly, each OAI duct (north and south) has both an A train and a B train isolation valve. Under a design basis accident scenario, all four OAI isolation valves would go closed. Control room operators, monitoring outside radiation levels, would then select either the north or south OAI duct as a makeup path and open the appropriate valves. While the existing test procedure provided verification that OAI flow can be throttled (to limit OAI to <450 cfm) from either the north side or the south side, procedurally it did not test the ability to throttle from the untested side.

Working in conjunction with the OAI valves are return air modulating dampers D-39 (A train) and D-40 (B train). These dampers are located in series in the common return duct and are controlled by a pressure differential indicating controller which is set at 1/8" w.g. The existing test procedure did not address these dampers. As such, both dampers were allowed to operate during the test which could result in masking a failed damper.

The control room Technical Specification surveillance procedure OP 2-1900050, "Control Room Pressure Periodic Test," was revised as 2-OSP-25.01, "Control Room Pressure Periodic Test," and a successful surveillance was completed on November 8, 1997. Operations declared CRECS back in service, and the Technical Specification ACTION statement exited.

The cause for the CRECS surveillance procedure deficiency was non-cognitive personnel error that occurred at the time of plant licensing during the development of surveillance procedure 2-1900050, "Control Room Pressure Periodic Test." The procedure as written did not meet the intent of the Technical Specification surveillance requirements because control room pressurization on an individual train basis was not adequately tested.

The existing test procedure did not adequately ensure that each individual train of the CRECS is capable of meeting its design requirements. This condition was determined to constitute a missed technical specification surveillance which is reportable per 10 CFR 50.73(a)(2)(i)(B), as a condition prohibited by technical specifications.

This situation is not applicable to Unit 1. Although the designs are generally similar, the Unit 1 and Unit 2 Technical Specifications treat the systems differently. The Unit 1 Technical Specifications refers to a singular "control room emergency ventilation system" which consists of two booster fans, two isolation valves in each duct, etc. whereas the Unit 2 Technical Specifications refers to "two independent control room emergency air cleanup systems." Though not a Technical Specification compliance issue, the Unit 1 control room pressure periodic test procedure was enhanced to provide for train specific testing.

NRC FORM 366A U.s. NUCLEAR REGULAToRY CQMMIsslo I4.95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST. LUCIE UNIT 2 05000389 4 OF 5 97 008 0 TEXT llfmore space is required, use additional copies of NRC cform 366Al l17)

For the purposes of this assessment the three train related components of system operation are discussed below. These train related components are: (1) kitchen and toilet exhaust valves; (2) north and south OAI valves; and (3) return dampers D-39 and D-40, Note that although there are A and B train emergency fans, these fans are separately tested to ensure proper performance; therefore, fan operability is not a train related aspect of the pressurization test.

The kitchen and toilet exhaust lines are each equipped with A and B train isolation valves. These valves form a part of the control room envelope and are required to isolate upon receipt of a containment isolation signal (CIS). The existing control room pressurization test did not demonstrate the ability of each individual train to provide an adequate boundary since the test required both the A and B valves to be closed prior to the test. Although they have not been periodically tested as a part of the pressurization test, the isolation valves have been verified to automatically close as a part of other plant testing.

Since these valves close upon receipt of a CIS, they are tested as a part of the integrated safeguards test procedure (Operating Procedure 1-0400050, Appendix 0). Although this testing does not demonstrate the leak, tightness of the valves, it does verify that the valves actuate to their closed position. With the valves closed, any leakage would be limited to relatively insignificant seat leakage rather than the gross leakage associated with a partially or fully open valve. The integrated safeguards testing is performed at the same frequency as the pressurization test (18 months).

The north and south OAI lines are each equipped with A and B train isolation valves. Control room operators, monitoring outside radiation levels, select either the north or south OAI duct as a makeup path and open the appropriate valve(s). The existing test procedure did not test the ability to use both the north and south intake ducts.

The ability to draw makeup air from either the north or south duct is not critical to system operation nor is the ability to remotely actuate the OAI valves. Failure of a makeup path is addressed in UFSAR Table 9.4-

3. This table notes that in the event one intake path becomes inoperable, the redundant path may be used and that the intake valve may be manually opened. Thus, the failure to test each OAI isolation valve does not significantly affect system operation.

Return dampers D-39 (A train) and D-40 (B train) are installed in series in the common air return duct. Each damper is controlled by its own pressure differential indicating controller and modulates to maintain a positive pressure in the control room. The existing test procedure did not address these dampers. Since both dampers were allowed to operate during the test, a failed damper could potentially go undetected.

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIO I4-96)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST. LUCIE UNIT 2 05000389 5 OF 5 97 008 0 TEXT (Ifmore space is required, use additional copies of NRC Form 366A] l17)

The dampers are designed to modulate in the open direction upon decreasing control room differential pressure and are designed to fail open upon a loss of power or a loss of control signal. Because the fail open position is beneficial from the standpoint of maintaining a positive pressure in the control room, the inability of the test procedure to identify a failed damper is not significant from a system performance standpoint.

Conclusion The failure of the previous TS surveillance procedure to verify individual CRECS train capability to pressurize the control room would not significantly increase the dose to operators during an event. The effects of postulated undetected failures are not significant enough to jeopardize the capability of the CRECS. Any postulated exhaust valve leakage would be limited to minor seat leakage such that the CRECS could still maintain the control room at a positive pressure. The ability to draw makeup air from either the north or south duct is not critical to system operation. The modulating return dampers are designed to modulate in the open direction upon decreasing control room differential pressure and are designed to fail open upon a loss of power or a loss of control signal. Therefore this event had no adverse impact on the health and safety of the public.

1) Operating Procedure 2-1900050, "Control Room Pressure Periodic Test," was revised to provide for train specific testing. This procedure was reissued as Operations Surveillance Procedure 2-OSP-25.01 on November 7, 1997.

2) Both trains of the control room emergency cleanup system were satisfactorily tested to the new test procedure on November 8, 1997.

3) All test procedures related to technical specification surveillances of HVAC systems were reviewed for adequacy with no additional issues identified.

None LER 389/97-007, "Inoperable Containment Cooling Fan Results in Operation of Facility Outside Design Basis."