ML17263A544

LER 94-002-00:on 940202,discoverd Containment Pressure Channels P-947 & P-948 Inoperable.Caused by Obstruction in Common Containment Pressure Sensing Line.Obstruction Cleared from Affected Tubing & Leak Tests performed.W/940304 Ltr

ML17263A544
Person / Time
Site:	Ginna
Issue date:	03/04/1994
From:	Mecredy R, St Martin J ROCHESTER GAS & ELECTRIC CORP.
To:	Andrea Johnson NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
LER-94-002, LER-94-2, NUDOCS 9403110108
Download: ML17263A544 (13)

Text

ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM

~ ,

I REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9403110108 DOC.DATE: 94/03/04 NOTARIZED: NO DOCKET g FACIL:50-244 Robert Emmet. Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION ST MARTIN,J.T. Rochester Gas & Electric Corp.

MECREDY,R.C. Rochester Gas & Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION JOHNSON,A.R. Project Directorate II-3

SUBJECT:

LER 94-002-00:on 940202,discoverd Containment Pressure channels P-947 & P-948 inoperable. Caused by obstuction intr. D, comman containment pressure sensing line. Inoperable channels defeated,bistables in tripped condition.W/940304 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR j ENCL /

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

SIZE: /

NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244 D

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL D PD1-3 PD 1 1 JOHNSON,A 1 1 INTERNAL: AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 1 NRR/DORS/OEAB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NQR/DRIL/RPEB 1 1 NRR/DRSS/PRPB 2 2 RR/ISSSA/ PLB 1 1 NRR/DSSA/SRXB 1 1 1 1 RES/DSIR/EIB 1 1 RGN1 FILE 01 1 1 EXTERNAL EG&G BRYCE F J ~ H 2 2 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A NSIC POORE,W. 1 1 NUDOCS FULL TXT 1

1 l.

1 D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOivI Pl-37 (EXT. 20079) TO FLIMINATEYOUR NAME FROiil DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 27 ENCL 27 A

t r~

~ ' ~ i e 5 mart 51Att ROCHESTER GAS AND ELECTRIC CORPORATION o 89 EAST AVENUE, ROCHESTER N.K 14649.0001 ROBERT C. MECREOY Vice President TELEPHONE'REA CODE 716 546 2700 Oinna Nuclear Production March 4, 1994 U.S. Nuclear Regulatory Commission Document Control Desk Attn: Allen R. Johnson Project Directorate I-3 Washington, D.C. 20555

Subject:

LER 94-002, Containment Pressure Transmitters Inoperable, Due to Blockage of Sensing Line by Corrosion Products, Causes a Condition Prohibited by Technical Specifications R.E. Ginna Nuclear Power Plant Docket No. 50-244 In accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (i) (B), which requires a report of, "Any operation or condition prohibited by the plant's Technical Specifications", the attached Licensee Event Report LER 94-002 is hereby submitted.

This event has in no way affected the public's health and safety.

Very truly yours, Robert C. Mecredy xc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna Senior Resident Inspector Zip&

9403110108 940304 PDR ADOCK 05000244 8 PDR f

NRC FORH 366 U.S. NUCLEAR REGULATORY COHHISSIOH APPROVED BY QGI NO. 3150-0104 (5.92) EXPIRES 5/31/95 EST IHATED BURDEN PER RESPONSE TO COHPLY WITH LICENSEE EVENT REPORT (LER) THIS INFORHATION COLLECTION REQUEST: 50.0 HRS.

FORWARD COMHENTS REGARDING BURDEH EST I HATE TO THE INFORMATION AND RECORDS -MANAGEHENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION/

(See reverse for required number of digits/characters for each block) WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3110-0104), OFFICE OF MANAGEMENT AND BUDGET WASHINGTON DC 20503.

FAcILITY NAME (1) R. E ~ Ginna Nuclear Power Plant DOCKET IRNIBER (2) PAGE (3) 05000244 10F 10 TITLE (4) Contaiwent Pressure Transmitters Inoperable, Due to Blockage of Sensing Line by Corrosion Products, Causes a Condition Prohibited by Technical Specifications EVENT DATE 5 LER NUIBER 6 REPORT DATE 7 OTHER FACILITIES INVOLVED 8 HONTH SEQUENTIAL REVISION FACILITY NAME DOCKET NUHBER DAY YEAR YEAR HONTH DAY YEAR NUMBER NUHBER 02 02 94 94 002-- 00 03 04 94 FACILITY NAHE DOCKET NUHBER OPERATING THIS REPORT IS SUBHITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR  : Check one or mor e 11 (9) N 20.402(b)

HODE 20.405(c) 50.73(a)(2)(iv) 73.71(b)

POWER 20.405(a )(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c) 098 LEVEL (10) 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) OTHER 20.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) (Specify in 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Abstractand in Text, below 20.405(a)(1)(v) 50.73(a)(2)(iii) 50 '3(a)(2)(x) NRC Form 366A LICENSEE CONTACT FOR THIS LER 12 NAHE John T~ St. Hartin - Director, Operating Experience TELEPHONE NUMBER (Include Area Code)

(315) 524-4446 CQIPLETE ONE LINE FOR EACH C(NPONENT FAILURE DESCRIBED IN THIS REPORT 13 CAUSE REPORTABLE REPORTABLE SYSTEH COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT HANUFACTURER TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED 14 HONTH DAY YEAR EXPECTED YES SUBHISSION (If yes, complete EXPECTED SUBHISSION DATE). X NO DATE (15)

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

On February 2, 1994, at approximately 1642 EST, with the reactor at approximately 98% steady state power, Control Room operators determined that Containment Pressure channels P-947 and P-948 were inoperable.

Based on post-event review of computer data, this condition was in violation of Technical Specification Table 3.5-2 Action Statements.

Immediate corrective action was to defeat the inoperable channels by placing the affected bistables in the tripped condition.

The underlying cause of the event was an obstruction in the common containment pressure sensing line for P-947 and P-948.

Corrective action was taken to clear the obstruction from the affected tubing, leak test the penetration piping and transmitter tubing, and verify the proper operation of P-947 and P-948.

Corrective action to preclude repetition is outlined in Section V (B).

NRC FORM 366 (5 92)

NRC FORM 366A U.S. NUCLEAR REGULATORY CQIIISSION APPROVED BY QGI NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MANAGEMEN'I BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (31i0.0104), OFFICE OF MANAGEMENT AND BUDGET WASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NLNBER 2 LER NUMBER 6 PAGE 3 SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 94 -- 002 00 2 OF 10 TEXT (If more space is required, use additional copies of HRC Form 366A) (17)

PRE-EVENT PLANT CONDITIONS The plant was at approximately 984 steady state reactor power with no major activities in progress. Instrument and Control (I&C)

Department personnel were investigating Containment Pressure channel P-947. This investigation was initiated by a Maintenance Work Request / Trouble Report (MWR/TR) written January 20, 1994 by Control Room operators because the Main Control Board pressure indication for P-947 (PI-947) was observed to be reading slightly lower than the indication for Containment Pressure channels P-945 and P-949 (PI-945 and PI-949), which are also on the Main Control Board.

II. DESCRIPTION OF EVENT A. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES:

o June 24, 1992, 1500 EDST: Containment (CNMT) pressure channel P-947 output indication starts to become inconsistent with channels P-945 and P-949, as monitored on the Plant Process Computer System (PPCS). (This is based on post-event review of archived data on the PPCS.) Event date and time.

o January 20, 1994: Control Room operators submit MWR/TR on PI-947 Main Control Board indication.

o February 2, 1994, 1642 EST: Discovery date and time.

o February 4, 1994, 0007 EST: Containment Pressure channel P-947 is restored to operable status.

o February 4, 1994, 1536 EST: Containment Pressure channel P-948 is restored to operable status.

HRC FORM 366A (5 9?)

NRC FORM 366A U S NUCLEAR REGULATORY CQIIISSION APPROVED BZ CHB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECT ION REQUEST: 50.0 HRS.

FORWARD COMMENTS REGARDING BURDEH ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHIHGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150 0104), OFFICE OF MANAGEMENT AND BUDGET WASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NMBER 2 LER NINBER 6 PAGE 3 YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant M R M 05000244 94 002-- 00 3 OF 10 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

B. EVENT:

On January 20, 1994, Control Room operators observed that one Main Control Board indication for CNMT pressure, PI-947,"was reading slightly lower than the other two indicators, PI-945 and PI-949. They initiated a MWR/TR, for I&C personnel to investigate the difference in readings. On January 21, I&C performed the annual calibration of the channel. The channel (P-947) responded properly to both the electronic checks and,to actual pressure signals inserted into the transmitter (PT-947).

After reviewing post-calibration trending data and archived PPCS computer traces of CNMT pressure, I&C noticed that channel P-947 was still not tracking consistent with channels P-945 and P-949.

Further investigation was conducted on February 2, 1994, to identify if there could be any possible mechanical and/or electrical problems with P-947.

On February 2, 1994, at approximately 1612, EST, with the reactor at approximately 98%,steady state reactor power, Control Room operators declared channel P-947 inoperable. The affected bistables were placed in the tripped condition. To verify the operability of the redundant CNMT pressure channels, the operators then caused a small change in CNMT pressure by depressurizing CNMT per operating procedure 0-11, "Control of Mini Purge Exhaust Valves While Depressurizing Containment".

I&C personnel monitored test points for CNMT pressure channels P-945, P-947, P-948, and P-949 with a digital multimeter.

During this depressurization, at approximately 1642 EST, two channels (P-947 and P-948) did not show any response to the small change in CNMT pressure.

The'Control Room operators formally declared P-948 inoperable at approximately 1658 EST. The affected bistables were placed in the tripped condition per emergency restoration procedure ER-INST.1, "Reactor Protection Bistable Defeat After Instrumentation Loop Failure". P-947 and P-948 sense CNMT pressure via a common line (CNMT Penetration 203A). A CNMT entry was made to verify that this sensing line for PT-947 and PT-948, (Pen. 203A) was not mechanically blocked. Pen. 203A was visually verified not to be externally obstructed. The valve lineups for the pressure transmitters (PT-947 and PT-948) were verified to be correct.

HRC FORM 366A (5-92)

NRC FORM 366A U.S. NUCLEAR REGULATORY CQIIISSI ON APPROVED BY CSQ NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPOHSE TO COMPLY MITH THIS INFORMATION COLLECTIOH REQUES'I: 50.0 HRS.

FORllARD COMMENTS REGARDIHG BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (MNBB 7714), U.ST NUCLEAR REGULATORY COMMISSIONS HASHIHGTOH, DC 20555-0001 AHD TO THE PAPERIJORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET 'WASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NtMBER 2 LER NINBER 6 PAGE 3 SEOUEHTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 YEAR 94 -- 002-- 00 4 OF 10 TEXT (If more space is required, use additional copies of HRC Form 366A) (17)

On February 3, 1994, a work package for troubleshooting and repair of the CNMT penetration line was prepared. A CNMT entry was made and Pen. 203A was pressurized to thirty (30) pounds per square inches above atmospheric pressure (PSIG), using surveillance test procedure PTT-23.17B, "Containment Isolation Valve Leak Rate Testing Containment Pressure Transmitters PT-947 and PT-948 Pen 203A". PT-947 and PT-948 did not respond to this pressure, which indicated a blockage in the piping for Pen. 203A or in the common instrument tubing line. Backflushing with one-hundred-twenty (120) PSIG air supply to clear the blockage was unsuccessful.

Pen. 203A was isolated inside CNMT to provide double barrier isolation for CNMT integrity. The instrument tubing was disconnected outside CNMT. The instrument tubing was found to contain water, but. this water was not the source of the blockage. The 1/t2 inch carbon steel tubing for Pen. 203A was found to be mechanically blocked with a thick sludge. The blockage was removed. The tubing was reassembled and preparations were made to test the tubing.

I On February. 3, 1994, at approximately 2207 EST, Pen. 203A was declared inoperable to perform required Appendix J testing. The Limiting Condition for Operation (LCO) for Technical Specification (TS) 3.6.3.1. was entered. Pen. 203A was tested in accordance with surveillance test procedure PTT-23.17B, "Containment Isolation Valve Leak Rate Testing Containment Pressure Transmitters PT-947 and PT-948 Pen 203A". It was documented in PTT-23.17B that PT-947 and PT-948 now accurately responded when the penetration was pressurized to 60 PSIG. PTT-23.17B was successfully completed at approximately 2336 EST and Pen. 203A was declared operable at approximately 2340 EST.

OnFebruary 4, 1994, at approximately 0007 EST, P-947 was declared operable.

The transmitter and rack calibration procedure for channel P-948 was performed later in the day on February 4, and P-948 was declared operable at approximately 1536 EST on February 4, 1994.

C~ I NOPERABLE 'TRUCTURES i COMPONENTS i OR SYSTEMS THAT CONTRI BUTED TO THE EVENT:

None NRC FORM 366A (5 92)

HRC FORH 366A U.S NUCLEAR REGULATORY CQIIISSIOH APPROVED BY QGI NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COMPLY MITH THIS INFORHATIOH COLLECTION REQUEST: 50.0 HRS.

FORNARD COHMENI'S REGARDIHG BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS HANAGEHEHT BRAHCH TEXT CONTINUATION (MHBB 7714), U.S. NUCLEAR REGULATORY COMHISSION, llASHINGTOH, DC 20555-0001 AND TO THE PAPERNORK REDUCTION PROJECT (3140-0104), OFFICE OF HANAGEMENI'ND BUDGET LIASHINGTON DC 20503.

FACILITY NAHE 1 DOCKET NINBER 2 LER HI%GER 6 PAGE 3 YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 94 -- 002-- 00 5 OF 10 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:

Engineered Safety Features that rely on CNMT pressure inputs are Safety Injection Actuation (SI), Steam Line Isolation, and Containment Spray Actuation (CNMT Spray). None of these features was affected by the inoperability of P-947 and P-948, because at no time, from 'June 24, 1992, to February 4, 1994, was CNMT pressure at or near the actuation setpoints (4 PSIG for SI, 18 PSIG for Steam Line Isolation, and 28 PSIG for CNMT Spray).

During this period, the redundant channels (for P-94'7 the channels are P-945 and P-949; for P-948 the channels are P-946 and P-950) were in service and were not taken out of service unless the affected bistables were placed in the tripped condition.

E. METHOD OF DISCOVERY:

This event was first identified due to the astute observation of a Control Room operator on January 20, 1994, who questioned a slight difference in indications for CNMT pressure. The small deviation between redundant channels was within the tolerance of Main Control Board instrumentation channel checks.

The monthly Channel Functional Tests and annual Channel Calibrations associated with these channels (as required by TS Table 4.1-1 for units f17 and f25) did not detect the obstructed tubing line due to the location of the obstruction. The sludge was located between CNMT and the root isolation valves for PT-947 and PT-948. These root isolation valves are closed during performance of the necessary tests and calibrations, in order to pressurize the volume between the valve and the pressure transmitter. This method of testing is consistent with the definition of Channel Functional Testing, as defined in TS 1~7~3~a ~

The fact that this event affected both channels P-947 and P-948 was identified as a result of the investigations performed by I&C personnel on February 2, 1994.

A more detailed review of the archived PPCS records of CNMT pressure concluded that channel P-947 had not responded to changes in CNMT pressure since June 24, 1992, beginning at approximately 1500 EDST.

HRC FORH 366A (5-92)

NRC FORH 366A U.S. NUCLEAR REGULATORY CQOII SSION APPROVED BY 0KB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPOHSE TO COHPLY WITH THIS IHFORHATION COLLECTIOH REQUEST: 50.0 HRS.

FORWARD CONNENTS REGARDING BURDEN ESTIHATE TO LICENSEE EVENT REPORT (LER) THE IHFORHATIOH AND RECORDS NANAGEHEHT BRANCH TEXT CONTINUATION (HHBB 7714), U.S. NUCLEAR REGULATORY CONHISSIONg WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140.0104), OFFICE OF NANAGENENT AND BUDGET WASHINGTON DC 20503.

FACILITY NANE 1 DOCKET NIMBER 2 LER NIMBER 6 PAGE 3 SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 YEAR 94 -- 002-- 00 6 OF 10 TEXT (If more space is required, use additionnI copies of NRC Form 366A) (17)

Note that while CNMT pressure channel P-947 is monitored by the PPCS, channel P-948 is not. In addition, PI-948 (and also PI-946 and PI-950) have a scale of 10 to 200 PSIA (absolute pressure). By comparison, PI-947 (and also PI-945 and PI-949) have a scale of 0 to 60 PSIG.

It is assumed that P-948 had not responded to changes in pressure for the same amount of time as P-947.

CNMT F. OPERATOR ACTION:

The Control Room operators observed that the PI-947 reading was inconsistent on January 20, 1994, and initiated 'a MWR/TR. After both channels P-947 and P-948 were discovered to be inoperable, the Control Room operators performed emergency restoration procedure ER-INST.1 and placed the affected bistables in the tripped condition.

Subsequently, the Control Room operators ensured that higher supervision and the NRC Resident Inspector had been notified of this event.

G. SAFETY SYSTEM RESPONSES:

None III. CAUSE OF EVENT A. IMMEDIATE CAUSE:

The immediate cause of the event was the failure of P-947 and P-948 to respond to changes in CNMT pressure due to obstruction of the common pressure sensing line.

B. INTERMEDIATE CAUSE:

The intermediate cause of the obstruction of the common pressure sensing line at Pen. 203A was a buildup of corrosion products in this line, which is 1/2 inch OD, 0.065 inch wall thickness, carbon steel tubing. These corrosion products were visually examined and found to be reddish brown/black in color, visually resembling iron oxide scale.

HRC FORH 366A (5-92)

NRC FORM 366A U.S NUCLEAR REGULATORY C(NHISSIOH APPROVED BY INIB NO. 3'150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY IJITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORIJARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE IHFORMATIOH AHD RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (MHBB 7714), U.S+ NUCLEAR REGULATORY COMMISSIOH, IJASHINGTOH, DC 20555-0001 AND TO THE PAPERIJORK REDUCTION PROJECT (31(0-0104), OFFICE OF MANAGEMENT AHD BUDGET IJASHIHGTON DC 20503.

FACILITY NAME 1 DOCKET HINBER 2 LER HINBER 6 PAGE 3 SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 YEAR M

94 -- 002 00 7 OF 10 TEXT (If more space is required, use additional copies of HRC Form 366A) (17)

C. ROOT CAUSE:

The underlying cause of the buildup of corrosion products (iron oxide scale) was the method of transmitter calibration coupled with sensing line configuration. I&C personnel have calibrated these transmitters with a water-filled deadweight tester for many years. The configuration of the transmitter and sensing line prevented the drainage of all the water after calibration.

After the transmitter was unisolated as part of the calibration process, the trapped water traveled down to the low portion of the sensing line.

Stagnant water has remained in the carbon steel sensing lines for a substantial period of time. Under such conditions, sig-nificant corrosion of the carbon steel material can occur. The corrosion product, hydrated iron oxide (common rust) is voluminous, occupying many times the volume of the material lost to the corrosion process. Sufficient corrosion product accumulated to block the sensing line tubing, resulting in the inoperability of P-947 and P-948.

IV. ANALYSIS OF EVENT This event is reportable in accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (i) (B), which requires a report of, "Any operation or condition prohibited by the plant's 'Technical Specifications". CNMT pressure channels P-947 and P-948 were inoperable for a considerable length of time, in violation of TS Table 3.5-2, units g 1.b., 2.b., and 5.c. Operation in this condition since June 24, 1992 is a condition prohibited by TS.

An assessment was performed considering both the safety consequen-ces and implications of this event. The results of this assessment are that there were no operational or safety consequences or implications attributed to the inoperability of P-947 and P-948 because:

o A review of plant history and preventive maintenance history files has shown that the redundant CNMT pressure channels (P-945, P-946, P-949, and P-950) have been either operable or placed in the conservative tripped state from the Event date to the Discovery date.

NRC FORM 366A (5-92)

NRC FORM 366A U.S NUCLEAR REGULATORY COtlISSIOH APPROVED BT QQ NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY IIITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS ~

FORIJARD COMMENTS REGARDIHG BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (HHBB 7714), U.S. NUCLEAR REGULATORY COMMISSION,

'MASHIHGTON, DC 20555-0001 AHD TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET IIASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NINBER 2 LER HINIBER 6 PAGE 3 YEAR SEQUENTIAL REVISION R.E. Ginna Nuclear Power Plant 05000244 94 -- 002-- pp 8 OF 10 TEXT (lf more space is required, use additional copies of NRC Form 366A) (17) o A review of PPCS data has shown that the redundant pressure channels have responded to pressurization of the sensing lines and pressure changes in CNMT. Thus, these redundant channels did not exhibit the same failure mode as P-947 and P-948.

0 The 2 out of 3 logic (2/3) required for actuation of SI was reduced to 'a 2/2 logic with the inoperability of P-947. Thus SI actuation from high CNMT pressure (4 PSIG) would have occurred as assumed in the design basis.

0 The diverse actuation circuitry for SI has three additional means of actuation (steam generator low steam pressure, pressurizer low pressure, and Manual). None of these diverse means was affected by the inoperability of P-947.

The 2/3 logic required for Steam Line Isolation actuation was reduced to a 2/2 logic with the inoperability of P-948.

Thus, Steam Line Isolation actuation from high-high CNMT pressure (18 PSIG) would'have occurred as assumed in the design basis.

0 The diverse actuation circuitry for Steam Line Isolation has three additional means of actuation (hi-hi steam flow with safety injection, hi steam flow and 2/4 low Tavg with safety injection, and Manual). None of these diverse means was affected by the inoperability of P-948.

o The 2/3 plus 2/3 logic required for CNMT Spray actuation was reduced to a 2/2 plus 2/2 logic with the inoperability of P-947 and P-948. Thus, CNMT Spray actuation from high-high CNMT pressure (28 PSIG) would have occurred as assumed in the design basis.

o The alternate actuation circuitry for CNMT Spray (Manual) was not affected by the inoperability of P-947 and P-948.

Based on the above, and safety was assured it atcan all be concluded times.

that the public's health NRC FORM 366A (5-92)

NRC FORM 366A U.S. NUCLEAR REGULATORY CQOIISSION APPROVED BY QQ NO. 3150-0104 (5.92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY lllTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORNARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AHD RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (MHBB 7714), U.S. NUCLEAR REGULATORY COMMISSION/

WASHINGTON, DC 20555-0001 AHD TO THE PAPERNORK REDUC'TIOH PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET IIASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NNSER 2 LER NHIBER 6 PAGE 3 YEAR SEQUENTIAL RE VIS IOH R.E. Ginna Nuclear Power Plant 05000244 94 002 pp 9 OF 10 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

V. CORRECTIVE ACTION A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:

o The iron oxide scale was removed from the sensing line and P-947 and P-948 were restored obstructed'enetration to operable status.

o The other channels that monitor CNMT pressure were verified to respond to small changes in CNMT pressure.

B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:

o PPCS computer points for CNMT pressure will be archived daily until the 1994 refueling outage to verify channel operability.

o The sensing lines for all CNMT pressure channels will be inspected and cleaned out during the 1994 refueling outage.

o The method of calibration of the CNMT pressure transmitters has been changed to use gas (instead of water) as the test medium.

o Testing these containment penetrations has been enhanced to include formal documentation of pressure channel response.

HRC FORM 366A (5 92)

NRC FORM 366A U.S. NUCLEAR REGULATORY CQIIISSION APPROVED BY QUI NO. 3150-0104 (5-92) EXPIRES 5/31/95 ES'IIMATED BURDEN PER RESPONSE TO COMPLY lllTH THIS INFORMATION COLLECTIOH REOUEST: 50.0 MRS.

FORNARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (MHBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERMORK REDUCTION PROJECT (3110-0104), OFFICE OF MAHAGEHEHT AHD BUDGET WASHINGTON DC 20503.

FACILITY NAME 1 DOCKET NUMBER 2 LER NMBER 6 PAGE 3 YEAR SEQUENTIAL REVISIOH R.E. Ginna Nuclear Power Plant 05000244 94 -- 002 pp 10 OF 10 TEXT (lf more space is required, use additional copies of HRC Form 366A) (17)

VI. ADDITIONAL INFORMATION A. FAILED COMPONENTS:

There were no failed components. The obstructed sensing line is 1/2 inch OD, 0.065 inch wall thickness, carbon steel tubing.

Information about the vendor and manufacturer is not relevant to this event.

B. PREVIOUS LERs ON SIMILAR EVENTS:

A similar LER event historical search was conducted with the following results: LER 92-003 was also an event caused by an obstructed pressure sensing line. However, the obstruction was caused by buildup of sludge from normal impurities in the process fluid (feedwater). The obstruction referred to in LER 94-002 was caused by corrosion from the interaction of the test medium and the sensing line materials.

C. SPECIAL COMMENTS:

None NRC FORM 366A (5-92)