ML18101B057

LER 95-022-00:on 950916,ABV Sys Exceeded Allowable Bypass Leakage Due to Tear in Expansion Joint Fabric.Caused by Equipment Failure.Expansion Joint Fabric Replaced

ML18101B057
Person / Time
Site:	Salem
Issue date:	10/13/1995
From:	ODONNELL P Public Service Enterprise Group
To:
Shared Package
ML18101B056	List: ML18101B055 ML18101B057
References
LER-95-022, LER-95-22, NUDOCS 9510200284
Download: ML18101B057 (8)

Text

NRC FORM 366. U.S. NUCLEAR REGULATORY COMMISSIO APPROVED BY OMB NO. 3150-0104 (4-95) EXPIRES 04/30198 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST: 60.0 HRS. LICENSEE EVENT REPORT (LER) REPORTED LESSONS LEARNED ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY.

FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION (See reverse for required number of AND RECORDS MANAGEMENT BRANCH (T.e U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20 55-0001, AND TO digits/characters for each block) THE PAPERWORK REDUCTION PROJECT gJ50-0104), OFACE OF MANAGEMENT AND BUDGET, WASHINGTON, 20503. FACILITY NAllE (1) DOCKET NUllBER (2) PAGE (3) SALEM GENERATING STATION, UNIT 1 05000272 1 OFS TITLE (4) Condition Prohibited the Plant Technical Specifications:

Auxiliary Building Ventilation System Exceeded Allowable Bypass Lea age Due to a Tear in an Expansion Joint Fabric EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8) MONTH YEAR I FACILITY NAME DOCKET NUMBER DAY YEAR SEQUENTIAL I REVISION MONTH DAY YEAR NUMBER NUMBER 05000 09 13 95 95 022 00 10 13 95 FACILITY NAME DOCKET NUMBER --05000 OPERATING 6 THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §:(Check one or more) (11) MODE(9) 20.2201(b) 20.2203(a)(2)(v) x 50. 73(a)(2)(i)(B)

50. 73(a)(2)(viii)

POWER 0 20.2203(a)(1) 20.2203(a)(3)(i)

50. 73(a)(2)(ii)

50. 73(a)(2)(x)

LEVEL(10) 20.2203(a)(2)(i) 20.2203(a)(3)(ii)

50. 73(a)(2)(iii) 73.71

• 20.2203(a)(2)(ii) 20.2203(2)(4)

50. 73(a)(2)(iv)

OTHER 20.2203(a)(2)(iii) 50.36(c)(1)

50. 73(a)(2)(v)

Abstract below or In C Form 366A 20.2203(a)(2)(iv) 50.36(c)(2)

50. 73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (12) NAME TELEPHONE NUMBER (Include Area Coda) Philip O'Donnell, Technical Engineer (609) 339-2041 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE llllll TONPRDS CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TONPRDS E VF EXJ uooo NO II SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY YEAR IYES XINO SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE). DATE(15) ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) *-' On September 16, 1994, a small tear was discovered in the inlet expansion joint fabric for the Auxiliary Building Ventilation System. A work order was initiated to replace the expansion joint. In January of 1995, the System Manager conducted a system walkdown and noticed that the tear was approximately 5 inches long. By August 3, 1995, the tear had deteriorated to an unacceptable level. On September 13, 1995, it was determined that it was probable that the tear had reached an unacceptable level prior to unit shutdown on May 17, 1995. Based on this conclusion, this incident is being reported in accordance with 10CFR50.73(a) ( 2) (i) (B) . The apparent cause of this event was equipment failure. The apparent cause of allowing the tear to reach an unacceptable level was a failure to correct a condition adverse to quality in a timely manner. Corrective actions include replacing the expansion joint, strengthening Program, augmenting the communications relative 9510200284 951013 PDR ADOCK 05000272 S PDR surveillances with increased to design basis issues. the Corrective Action walkdowns, and formal NRC FORM 366A 15-92) U.S. NUCLEAR REGULA TORY COMMISSION LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME 111 SALEM UNIT 1 DOCKET NUMBER 121 05000272 TEXT llf more space is required, uae additional copies of NRC Form 366AJ 1171 PLANT AND SYSTEM INFORMATION Westinghouse

-Pressurized Water Reactor APPROVED BY OMB NO. 3160..0104 EXPIRES 6/31 /95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH IMNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20655-0001, AND TO THE PAPERWORK REDUCTION PROJECT 13150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. YEAR 95 LER NUMBER 161 SEQUENTIAL NUMBER 022 REVISION NUMBER 00 PAGE 131 2 OF8 Auxiliary Building Ventilation System -EIIS Identifier

{VF} IDENTIFICATION OF OCCURRENCE Discovery Date: Report Date: Problem Report: September 13, 1995 October 13, 1995 950803367 DESCRIPTION OF OCCURRENCE On September 16, 1994, while performing maintenance troubleshooting for an unusual noise coming from the suction side of the 13*Auxiliary Building Ventilation System Exhaust Fan, maintenance personnel discovered a small tear in the inlet expansion joint fabric for the Auxiliary Building Ventilation System. A corrective maintenance work order was initiated to replace the expansion joint and was appropriately assigned a priority that indicated that the work was required to be done during an outage. It cannot be confirmed whether system operability was considered in establishing the priority.

In January 1995, during a system walkdown, the System Manager noticed this tear, which was approximately 5 inches long at that time. The tear was documented on Action Request 950113210, which was initiated on January 13, 1995. The System Manager also initiated an Equipment Malfunction Identification System tag at this point. Although documentation of a system operability determination could not be located, the equipment was later confirmed to be operable in this condition.

Salem Unit 1 entered a forced outage on February 4, 1995, which lasted throughout the month. The 13 Auxiliary Building Exhaust Fan Expansion Joint was not replaced at this time. It has been determined that the work order was never placed on the forced outage list and was not considered for inclusion in the forced outage. NRC FORM 366A (5-92)

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NRC FORM 366A (5-921 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME 111 SALEM, UNIT 1 DOCKET NUMBER 121 05000272 TEXT (If more 1pac11 i1 required, use additional copiH of NRC Fonn 366AI 1171 DESCRIPTION OF OCCURRENCE APPROVED BY OMB NO. 3150-0104 EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH TlilS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 77141. U.S. NUCLEAR REGULATORY COMMISSION.

WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT 13150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. YEAR 95 LER NUMBER 161 SEQUENTIAL NUMBER -022 REVISION NUMBER 00 PAGE 131 3 OF 8 On August 3, 1995, while Salem Unit 1 was in Cold Shutdown, the System Manager initiated Action Request 950803367 documenting the fact that the tear had not yet been repaired, and that the condition of the expansion joint tear had deteriorated to an unacceptable level (approximately 4 feet). At this time, the Auxiliary Building Ventilation System (which is required to be operable in modes 1, 2, 3, and 4 only) was declared inoperable.

The system was declared inoperable because it was determined that Technical Specification 4.7.7.1.b.1 could not be met. This Technical Specification requires that bypass flows not exceed 1%. Although this surveillance test was not due, and was not being performed, the system was declared inoperable based on the size of the tear. On August 10, 1995, the expansion joint fabric was replaced.

On September 13, 1995, a memo was generated by the System Engineering Support group in response to Action Request 950803367.

The purpose of the memo was to address operability of the Auxiliary Building Ventilation System prior to unit shutdown in May. The memo concluded that it is probable that the tear exceeded the size which would allow more than 1% bypass flow sometime prior to the shutdown on May 17, 1995. Based on this conclusion, and the requirement for the Auxiliary Building Ventilation System to be operable in modes 1, 2, 3, and 4, it was determined that this incident is reportable in accordance with 10CFR50.73(a)

(2) (i) (B) as an operation or condition prohibited by plant Technical Specifications.

ANALYSIS OF OCCURRENCE Technical Specification 3/4.7.7, Auxiliary Building Exhaust Air Filtration System, requires at least one Auxiliary Building Exhaust Air HEPA Filter Train associated with one charcoal adsorber bank, and at least two Exhaust Fans, to be operable in Modes 1, 2, 3, and 4. The basis for this Technical Specification requirement is that the operability of the Exhaust Air Filtration System will ensure that radioactive material leaking from the Emergency Core Cooling System (ECCS) equipment following a Loss of Coolant Accident (LOCA) is filtered prior to reaching the environment.

The tear was on the suction side of the fans,' downstream of the filtration system, and, therefore; allowed unfiltered air from the Auxiliary Building to be released to the environment via the plant vent stack. Although the tear allowed unfiltered air to exhaust through the plant vent, the only time that this would be a concern is in the event of a LOCA. The tear was on the 122 foot elevation, near the Auxiliary Building Ventilation System equipment, not in the vicinity of the ECCS equipment.

NRC FORM 366A (5-921 NRC FORM 366A 15-921 U.S. NUCLEAR REGULA TORY COMMISSION LICENSEE EVENT REPORT (LERI TEXT CONTINUATION FACILITY NAME 111 SALEM, UNIT 1 DOCKET NUMBER 121 05000272 TEXT (If more *pace I* required, u*e additional copla. of NRC Fann 366AI 1171 ANALYSIS OF OCCURRENCE

• APPROVED BY OMB NO. 3160-0104 EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH IMNBB 77141. U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT 13150-01041, OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. YEAR 95 LER NUMBER 161 SEQUENTIAL NUMBER 022 -REVISION NUMBER 00 PAGE 131 4 OF 8 An analysis has been performed to determine the size of the tear that would allow a bypass flow of 1% of the Technical Specification flow rate of 21,400 CEM +/-10%. If the bypass flow exceeds this amount, Technical Specification 4.7.7.1.b cannot be met. During surveillances, the bypass leakage has historically been well within the Technical Specification limits. It is estimated that an opening of approximately 5 square inches in the expansion joint fabric would allow a flow rate of approximately 214 CEM. Based on the amount of deterioration in the expansion fabric between January and August, it is assumed that the size of the opening would have exceeded 5 square inches prior to unit shutdown in May. This assumption is based on a constant rate of expansion for the tear. The tear was originally discovered in time to perform maintenance prior to the time that the tear deteriorated to the size that required the system to be declared inoperable, and subsequently to be determined to be reportable.

Maintenance was not conducted on the tear in a timely manner because the potential safety significance of the tear was not realized by plant personnel.

This is attributed to a lack of a questioning attitude, a failure to re-verify the status of equipment tagged with an Equipment Malfunction Identification System tag, and a lack of understanding of the design basis for the ventilation system. As a result, the corrective maintenance work order was not placed on the forced outage list and was not completed in a priority manner. This LER is being submitted in accordance with 10CFR50.73(a)

(2) (i) (B), any operation or condition prohibited by the plant's Technical Specifications in that it is assumed that the requirements of Technical Specification 3/4.7.7 were not complied with for some period of time between January and May. The requirements of the Technical Specification were not complied with because the plant staff was aware that the size of the tear had become unacceptable.

SAFETY SIGNIFICANCE The offsite and control room dose consequences of a LOCA are analyzed in Design Calculation S-C-CAV-MDC-1464, Emergency Air Conditioning System Dose Analysis.

NRC FORM 366A 15-921

., NRC FORM 366A (5-921 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LERI TEXT CONTINUATION e APPROVED BY OMB NO. 3160-0104 EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH IMNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION.

WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT 13150-01041, OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 161 PAGE 131 SALEM, UNIT 1 05000272 YEAR SEQUENTIAL REVISION 5 OF 8 NUMBER NUMBER 95 -022-00 TEXT (If more space is required, use additional copies of NRC Form 366A) (171 SAFETY SIGNIFICANCE 10CFR50, Appendix A, Criterion 19 identifies a limit of 5 rem whole body, or its equivalent to any part of the body, for control room personnel.

The 1974 paper by Murphy and Campe on control room ventilation system design for compliance with General Design Criteria (GDC) 19 provides guidance with respect to the "equivalent" dose. A beta skin dose limit of 30 rem and a thyroid dose limit of 30 rem are identified.

Furthermore, Standard Review Plan 6.4, "Control Room Habitability", also identifies 30 rem limits for beta skin and thyroid doses. 10CFR100 identifies exclusion area and low population zone exposure limits of 25 rem whole body and 300 rem to the thyroid. The PSE&G design calculation results indicate that the smallest margins are associated with the control room ahd site boundary thyroid doses. Estimated thyroid doses assuming complete bypass of the charcoal filter following a Loss of Coolant Accident are: Control Room: Site Boundary:

41.5 rem 110 rem The degraded condition control room thyroid dose exceeds the GDC 19 guideline and is higher than the design calculation value. The estimated site boundary dose is within the lOCFRlOO guideline of 300 rem. Although the estimated control room thyroid dose for the degraded condition indicates that the thyroid dose limit is exceeded, another method of assessing the calculated control room dose is presented in draft EPRI Report RP 3480-03, "The Potential Impact of Using the NRC Proposed Revised Source Term (RST) for Currently Operating Reactors," issued in June 1994. This report compares control room dose results calculated for the currently used source term (TID-14844) and the revised source term proposed by the NRC (draft NUREG-1465).

The comparison indicates that whole body and beta skin doses were similar for both cases. However, the RST thyroid dose is significantly less than the TID based value. Applying this factor to the design basis and degraded condition results would reduce the expected thyroid doses to well within the GDC 19 limit of 30 rem. This alternate methodology is not the current design basis; however, it is being used to evaluate the safety significance of this discovered condition.

NRC FORM 366A 15-921 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LERI TEXT CONTINUATION

• APPROVED BY OMB NO. 3160-0104 EXPIRES 5/31/96 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 60.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH IMNBB 77141, U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20666-0001, AND TO THE PAPERWORK REDUCTION PROJECT OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 161 PAGE 131 SALEM, UNIT 1 05000272 YEAR 95 TEXT llf more apace I* required, uae additional copiea of NRC Fonn 366AI 1171 SAFETY SIGNIFICANCE SEQUENTIAL NUMBER -022 REVISION NUMBER 00 6 OF8 These calculations present a worst case scenario, by assuming a complete bypass of the charcoal filter. However, it is believed that this tear deteriorated gradually from January until August. Therefore, during the time period that the plant was operating (prior to May 17), a portion of the air would have been processed through the charcoal filter, and the resultant dose would have been somewhat less than indicated above. On the basis of this assessment of the potential sources following a LOCA at either Salem Generating Station Unit 1 or U1.it 2, it is concluded that the radiation protection provided for plant personnel at Salem Generating Station adequately meets the requirements of GDC 19. PRIOR SIMILAR OCCURRENCES Other issues involving ventilation systems at Salem Station have recently been reported (see LERs 272/95-006, 272/95-008, 272/95-017, 272/95-019, and 272/95-024, of these only 272/95-008 was caused by an equipment failure).

These issues suggest that a heightened awareness and understanding of licensing and design basis requirements associated with the ventilation systems is required.

In addition, the System Readiness Reviews have identified multiple deficiencies in the ventilation systems.*

A Problem Report has been initiated to evaluate the aggregate impact of these deficiencies.

A cumulative root cause evaluation will be performed so that corrective actions, in addition to those identified in the individual LERs, will be identified and corrected.

Various issues regarding the failure to perform operability assessments have also been identified recently (see LERs 272/95-008 and 311/95-004).

APPARENT CAUSE OF OCCURRENCE The apparent cause of the tear in the expansion joint fabric was equipment failure. The expansion joint fabric failed due to aging. This apparent cause has been validated during System Readiness Review walkdowns.

Expansion joints in various ventilation systems have been identified as requiring corrective maintenance.

This maintenance will be completed prior to restart. NRC FORM 366A 15-921 NRC FORM 366A (5*921 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT ILER) TEXT CONTINUATION FACILITY NAME (1) SALEM, UNIT 1 DOCKET NUMBER 121 05000272 TEXT (If more space i* required, use additional copies of NRC Form 366AI (171 APPARENT CAUSE OF OCCURRENCE

• APPROVED BY OMB NO. 3160-0104 EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 77141.

NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-01041.

OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. YEAR 95 LER NUMBER 161 SEQUENTIAL NUMBER --022 REVISION NUMBER 00 PAOE (31 7 OF8 The apparent cause that allowed the tear in the expansion joint to reach the unacceptable level was a failure to correct a condition adverse to quality in a timely manner. A contributing cause was that no Operability Determination was performed.

Therefore, the tear was not adequately assessed to determine the potential effects during accident conditions.

Planners, schedulers, and personnel performing maintenance walkdowns on the Auxiliary Building Ventilation System did not recognize the significance of the path for airborne radioactivity being released to the environment.

Another contributing cause was that after the tear was identified, it was not followed up on to determine if the tear degraded to the point that an Action Statement entry would be required.

CORRECTIVE ACTIONS The expansion joint fabric has been replaced.

The need for increased sensitivity to the potential for safety significance has been stressed to station personnel through the implementation of an improved Corrective Action Program and a formalized Operability Determination Process. The Auxiliary Building Ventilation System was declared inoperable as a result of this finding during the System Readiness Review. The System Readiness Reviews have been conducted on the critical systems for both Salem Unit 1 and Unit 2. During these reviews, walkdowns were conducted to identify similar issues, and previously identified issues were re-evaluated to ensure that they were given the proper significance.

Expansion joints in various ventilation systems have been identified as requiring corrective maintenance.

This maintenance will be completed prior to restart. The Auxiliary Building Ventilation System has been designated as a system that requires a periodic System Manager walkdown.

This walkdown will augment the surveillance procedure requirement to visually inspect the expansion joints every 18 months. NRC FORM 366A (5*921 NRC FORM 366A (5-921 U.6. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CLER) TEXT CONTINUATION FACILITY NAME 111 SALEM, UNIT 1 DOCKET NUMBER 121 05000272 TEXT (If more apace ia required, use additional copiea of NRC Form 366A) (171 CORRECTIVE ACTIONS

• APPROVED BY OMB NO. 3160-0104 EXPIRES 6/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY Willi THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 77141. U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20565-0001, AND TO THE PAPERWORK REDUCTION PROJECT (315CM>1041.

OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. YEAR 95 LER NUMBER 181 PAOE 131 SEQUENTIAL NUMBER 022 REVISION NUMBER 00 80F8 Clarification concerning the design, testing, and maintenance of the HVAC systems will be formally communicated to Design Engineering, System Engineering, Radiation Protection, Operations, Work Planning, and Maintenance persorinel prior to restart, or the applicable mode, as appropriate.

The work control process will be enhanced to ensure that Equipment Malfunction Identification System tags are being reverified.

Additionally, a new Work Management Program is being developed that will enhance the effectiveness of the maintenance program by coordinating the various aspects of the work management process into a comprehensive Work Management Program Manual. This manual will be issued by November 1, 1995. NRC FORM 366A (5-921