ML18101B229

LER 95-012-01:on 761211,analysis for TDAFP Encl Did Not Match as-built Conditions.Caused by Inadequate Verification of Assumptions in Calculations Performed of Evaluation Identified.Completed Design change.W/960215 Ltr

ML18101B229
Person / Time
Site:	Salem
Issue date:	02/15/1996
From:	HASSLER D V, WARREN C Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-95-012, LER-95-12, LR-N96040, NUDOCS 9602220060
Download: ML18101B229 (5)

Text

• Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038-0236 Nuclear Business Unit FEB 1 5 1996 LR-N96040 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:

LER 272/95-012-01 SALEM GENERATING STATION -UNIT 1 FACILITY OPERATING LICENSE NO. DPR-70 DOCKET NO. 50-272 This Licensee Event Report entitled "Adequacy of Turbine Driven Auxiliary Feed Water Pump Enclosures" is being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR50.73 (a) (2) (ii). Attachment SORC Mtg.96-019 JEH/tcp C Distribution LER File 3.7 9602220060 960215 PDR ADOCK 05000272 S PDR -11e rci\\fi is in \'ClLff h;,mds.

Clay Warren General Manager -Salem Operations 95-2168 REV. 6.94

• Attachment A The following items represent commitments that Public Service Electric & Gas (PSE&G) made to the Nuclear Regulatory Commission (NRC) relative to this LER (272/95-012-01). The commitments are as follows: 1. The HELB analyses for all spaces that contain air operated backdraft isolation dampers have been checked to ensure that no other overpressurization possibilities exist. 2. A modification that will eliminate overpressurization of the TDAFP enclosure in the event of a HELB will be completed prior to entry into Mode 2. 3. Details of this LER will be reviewed with Nuclear Engineering Department personnel to reinforce the importance of verifying that input assumptions are correct.

• NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (4--95) .. LICENSEE EVENT REPORT (LER) FACILITY NAME (1) TITLE (4) (See reverse for required number of digits/characters for each block) Salem Generating Station Unit 1

• APPROVED BY OMB NO. 3150-0104 EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST: 60.0 HRS. REPORTED LESSONS LEARNED ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY.

FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (T F33), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20666-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3160-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20603. DOCKET NIJllBER (2) PAGE (3) 05000 1 OF3 Adequacy of Turbine Driven Auxiliary Feed Water Pump Enclosures EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8) YEAR YEAR I SEQUENTIAL I REVISION NUMBER NUMBER MONTH FACILITY NAME MONTH YEAR Salem Generating Station-Unit 2 DAY DAY 05000311 95 012 01 02 15 96 FACILITY NAME DOCKET NUMBER 12 11 76 05000 OPERATING

• 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)

50. 73(a)(2)(i)

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

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

X 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 LICENSEE CONTACT FOR THIS LER (12) NAME TELEPHONE NUMBER (Include Area Code) Dennis V. Hassler, LER Coordinator 609 -339 -1989 CAUSE 'SYSTEM COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) COMPONENT MANUFACTURER REPORTABLE TO NPRDS CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED SUBMISSION DATE (15) MONTH DAY YEAR I YES (If yes, complete EXPECTED SUBMISSION DATE). ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) In early November 1995, during an evaluation of a condition adverse to quality report, it was discovered that assumptions in the High Energy Line Break (HELB) analysis for the turbine driven auxiliary feed water pump (TDAFP) enclosure did not match as-built conditions and could allow pressure in the enclosure to exceed the enclosure design pressure during a HELB. A structural analysis of the TDAFP enclosure has shown that it would not be operable during a HELB due to overpressurization.

The cause of this occurrence is attributed to inadequate verification of assumptions in the calculations performed to evaluate previously identi:ied as-built design deficiencies.

Corrective actions include a review o: other HELB calculation assumptions and completion of a design change to eliminate the TDAFP overpressure.

This condition is being reported in accordance 10CFR50.73(a)

(2) (ii). A four hour 10CFR50.72 notification was made on November 16, 1995. NRC FORM 366 (4-95)

• NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95) .. LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) Salem Generating Station -Unit 1 05000272 95 -012 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) PLANT AND SYSTEM IDENTIFICATION Westinghouse

-Pressurized Water Reactor Auxiliary Feedwater System (AF) {BA}* Auxiliary Building Ventilation System (ABS) {VF} PAGE (3) 2 OF 3 01

• Energy Industry Identification System (EIIS) codes and component function identifier codes appear in the text as {SS/CCC}.

IDENTIFICATION OF OCCURRENCE Event Date: Unit 1: December 11, 1976 (Initial Plant Criticality)

Unit 2: August 2, 1980 (Initial Plant Criticality)

Date Determined to be Reportable:

November 16, 1995 CONDITIONS PRIOR TO OCCURRENCE Unit 1: Unit 2: De fueled, Mode 5, 0 % Reactor Power 0 % Reactor Power There were no structures, components, or systems that were inoperable at the start of the event that contributed to the event. DESCRIPTION OF OCCURRENCE In early November 1995, during an evaluation of a condition adverse to quality report, it was discovered that assumptions the HELB analysis for the turbine driven auxiliary feed water pump (TDAFP) {BA/P} enclosure did not match as-built conditions and could allow pressure in the enclosure to exceed the enclosure design pressure during a HELB. The ABS 6 damper {VF/DMP} is located in the wall separating the TDAFP enclosure and the adjacent pipe chase. The ABS 6 damper automatically opens to protect the TDAFP enclosure from overpressurization during a HELB in the enclosure.

The HELB analysis performed for a steam line break in the TDAFP enclosure assumed that the ABS 6 damper opened instantaneously when the pressure in the enclosure reached the setpoint.

Delays actually exist between the pressure reaching the setpoint aGd the initiation of the opening stroke of ABS 6 damper, and the damper reaching the full open position.

The analysis also assumed that the damper full open position provided 100 percent of the damper opening for pressure relief. In the full open position the damper opening area is actually less than 100 percent. It has been determined that with these delays and the less than full open damper opening, the peak pressure in the enclosure following NRC FORM 366A (4-95)

• NRC F<YalM 366A (4-95) U.S. NUCLEAR REGULATORY COMMISSION FACILITY NAME (1) Salem Generating Station -Unit 1 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION DOCKET NUMBER (2) LER NUMBER (6) YEAR I SEQUENTIAL I REVISION NUMBER NUMBER 05000272 95 012 01 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) PAGE (3) 3 OF 3 a steam line break will exceed the design pressure of the TDAFP enclosure and result in the enclosure becoming inoperable.

SAFETY SIGNIFICANCE An assumed failure of the TDAFP enclosure resulting from overpressurization due to a steam line break would allow steam to escape to surrounding areas. The escaping steam has the potential to render equipment in the area, including the motor driven auxiliary feed water pumps, inoperable.

APPARENT CAUSE OF OCCURRENCE The cause of this occurrence is attributed to inadequate verification of assumptions in the calculations performed to evaluate previously identified as-built design deficiencies.

During that evaluation, the primary focus was on the deficiencies being evaluated and the input assumptions were not questioned.

PRIOR SIMILAR OCCURRENCES Two prior similar occurrences have been identified within the past five years. The first, as reported in LER 272/91-036-01, concerned incorrect input assumptions in the steam line break analyses.

The second, as reported in LER 272/95-027-00, concerned inaccurate assumptions in dose calculations.

Corrective actions taken in response to these events could not have prevented the event reported here. CORRECTIVE ACTIONS 1. The HELB analyses for all spaces that contain air operated backdraft isolation dampers have been checked to ensure no other overpressurization possibilities exist. 2. A modification that will eliminate overpressurization of the TDAFP enclosure in the event of a HELB will be completed prior to entry into Mode 2. 3. Details of this LER will be reviewed with Engineering Department personnel to reinforce the of verifying that input assumptions are correct. NRC FORM 366A (4-95) J