ML18106A642

LER 98-010-00:on 931019,reactor Pressure Vessel Insp Plugs Were Out of Configuration,Was Noted.Caused by Personnel Error.Proper Configuration Was Restored Shortly After Discovery Prior to Entering Mode 2.W/980601 Ltr

ML18106A642
Person / Time
Site:	Salem
Issue date:	06/01/1998
From:	Bakken A, Enrique Villar Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-98-010, LER-98-10, LR-N980262, NUDOCS 9806080268
Download: ML18106A642 (5)

Text

( .e PS~G Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038-0236 Nuclear Business Unit JUN -11998 LR-N980262 U. S. Nuclear Regulatory.Commission Document Control Desk Washington, DC 20555 Gentlemen:

LER 272/98-010-00 SALEM GENERATING STATION - UNIT 1 FACILITY OPERATING LICENSE NO. DPR-70 DOCKET NO. 50-272 This Licensee Event Report entitled " Reactor Pressure Vessel Inspection Plugs out of configuration." is being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR50.73(a)(2)(ii).

Sincerely,

..Jd-t.~

~r /),C. 'i3~/cJ:~

A. C. Bakken Ill General Manager -

Salem Operations Attachment EHV c Distribution LER File 3.7 9806080268 980601 PDR ADOCK 05000272 S PDR *l The power is in your hands.

95-2168 REV. 6/94

l NRC FqRM 366 U.S. NUCLE REGULATORY COMMISSION APPR D BY OMB NO. 3150-0104 (4-95) EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE. TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION RE~ST: 50.0 HRS.

REPORTED LESSONS LEARNED ARE INCORPO TED INTO THE LICENSEE EVENT REPORT (LER) Ll.CENSING PROCESS AND FED BACK TO INDUSTRY.

COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION FORWARD AND RECORDS MANAGEMENT BRANCH (T-6 F33k U.S. NUCLEAR

.(See reverse for required number of REGULATORY COMMISSI~ WASHINGTON, DC 205 5-0001\:AND TO THE PAPERWORK REDU ON PR~ECT (3150-0104), 0 FICE OF digits/characters for each block) MANAGEMENT AND BUDGET, WASHI GTON, DC 20503.

FACll.ITY NAME ( 1) DOCKET NUMBER (2) PAGE (3)

SALEM GENERATING STATION UNIT 1 05000272 1 OF 4 TITLE (4)

REACTOR PRESSURE VESSEL INSPECTION PLUGS OUT OF CONFIGURATION.

EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR I SE~UENTIAL UMBER IREVISION NUMBER MONTH DAY YEAR FACILITY NAME SALEM 2 DOCKET NUMBER 05000311 FACILITY NAME DOCKET NUMBER 10 19 93 98 - 010 - 00 06 01 98 OPERATING 3 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) 20.2203(a)(1) 20.2203 (a)( 3)(i) x 50.73(a)(2){ii) 50-73(a)(2)(x)

) 20.2203(a)(2)(i) 20.2203(a){3){ii) 50.73{a){2){iii) 73.71 20.2203(a){2)(ii) 20_2203(a){4) 50.73(a)(2){iv) OTHER 20.2203{a){2)(iii) 50.36(c){1) 50-73{a){2)(v) Specify in Abstract below or in NRC 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 Code)

E. H. Villar (Station Licensing Engineer) 609 339 5456 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONT DAY YEAR SUBMISSION rr IYES (lfyes, complete EXPECTED SUBMISSION DATE).

x INO DATE (15)

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

On April 3, 1998, with Salem Unit 1 in Mode 3, the system manager noted that some of the reactor pressure vessel nozzle inspection plugs were out of configuration during the pre-start up missile hazard inspection. Three of the inspection plugs (also known as sandboxes) were affected. These components serve as pressure relieving devices in the event of a large-break LOCA (i.e. failure of a reactor pressure vessel nozzle.) The as-found configuration of three of these nozzles was such that they might become a missile inside containment during an accident. Without these sandboxes properly secured, it is possible that in the event of a nozzle failure the sandboxes could become a missile previously unaccounted for in the analysis for a nozzle failure. The root cause of this event was not determined. However, the apparent cause of this condition is believed to be personnel (human) error. The inspection plugs were ~eturned to their proper configuration, the Unit 2 plugs were verified properly secured.

This Licensee Event Report (LER) is being made in accordance with 10 CFR

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

NRC FORM 366 (4-95)

I 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) PAGE (l) 05000272 YEAR I SEQUENTIAL NUMBER I REVISION NUMBER 2 OF 4 SALEM GENERATING STATION UNIT 1 98 010 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

PLANT IDENTIFICATION: -

Salem Generating Station - Unit 1 Public Service Electric and Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Date of Occurrence: October 19, 1993 Date of Identification: May 5, 1998.

Report Date: June XX, 1998.

CONDITIONS PRIOR TO OCCURRENCE:

Salem Unit 1 - Mode 3 at the time of discovery.

DESCRIPTION OF OCCURRENCE:

On April 3, 1998, with Salem Unit 1 in Mode 3, the system manager noted that some of the reactor pressure vessel nozzle inspection plugs were out of configuration during the pre-start up missile hazard inspection. Three of the inspection plugs (also known as sandboxes) were affected. These components serve as pressure relieving devices in the event of a large-break LOCA (i.e. failure of a reactor pressure vessel nozzle.) The as-found configuration of three of these nozzles was such that they might become a missile inside containment during an accident.

At the- time of identification, PSE&G believed that this condition resulted from the extensive work that had been performed during the unit prolonged (2.5 years) shutdown. However, on May 4, 1998, PSE&G determined that this configuration might have potentially existed while the Salem Unit 1 operated at power. Therefore, this event was conservatively reported under 10CFR50.72.b.2.i.and constitutes a reportable condition per 10CFR50.73.

There are eight reactor vessel nozzles in each of the Salem Units, and each nozzle has an access port through the cavity floor at the 104-foot elevation. These access ports are covered when the reactor cavity is flooded, but the covers are removed at all other times. Below each cover is a "sandbox", which is bolted to the fo0ndation, and at the lower portion of each sandbox is a blowout plug.

NRG FORM 366A (4-95)

NRG FORM l66A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (l).

05000272 YEAR I SEQUENTIAL NUMBER I REVISION NUMBER 3 OF 4 SALEM GENERATING STATION UNIT 1 98 010 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

DESCRIPTION OF OCCURRENCE (cont'd):

The purpose of these blowout plugs is to provide pressure relief in case of a failure of a reactor pressure vessel nozzle (UFSAR Section 3.8). Each plug is approximately 10 square feet in area and vents to the 104-foot elevation. The plug is designed to fail at approximately 900 pounds per square inch pressure. In this particular condition, one of the sandboxes was missing all of its. bolting and the other one was missing some of them (approximately 20 bolts). Without these sandboxes properly secured, it is possible that in the event of a nozzle failure the sandboxes could become a missile previously unaccounted for in the analysis for a nozzle failure.

Therefore, this event was reported under 10CFR50.72.b.2.i.and constitutes a reportable condition per 10CFR50.73.

CAUSE OF OCCURRENCE:

The root cause of this event was not determined. However, the apparent cause of this condition is believed to be personnel (human) error.

These access inspection ports are low maintenance items, and there is normally no reason to remove them. However, the sandboxes are removed during the periodic (10 year interval) inspection of the nozzles. For Salem Unit 1, this inspection took place during the lRll outage in 1993 under work order 930601187. This work order was taken to work complete on October 19, 1993.

A line item search (work order description) of the work order database did not reveal any work being performed since they were last removed for the ISI inspection. Therefore, the most probable cause of this event is associated with human performance issues, such as improper installation of these sandboxes following the 1993 ISI inspection.

PRIOR SIMILAR OCCURRENCES:

A review of the Salem LER database did not reveal any similar occurrence within the past two years.

SAFETY CONSEQUENCES AND IMPLICATIONS:

There were no safety consequences associated with this event.

The failure of a reactor pressure vessel nozzle is a limiting fault of improbable occurrence (Condition IV as defined in the Salem UFSAR) .

However, should this fault occur, a rapid pressure rise in these access ports will occur due to the nozzle failure.

NRC FORM 366A (4-95)

NRG FORM l66A (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3) 05000272 YEAR I SEQUENTIAL NUMBER I REVISION NUMBER 4 OF 4 SALEM GENERATING STATION UNIT 1 98 010 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

SAFETY CONSEQUENCES AND IMPLICATIONS (cont'd):

The failure point of the blGwout plugs is approximately 900 psig, and with a surface area of approximately 10 square feet without being properly restrained, there is considerable upward force on these plugs. Without the proper restraints, these plugs would become missiles, possibly impacting the control rod drive mechanisms (CRDM). The CRDM are the most likely target of these plugs.

However, the control rod drives are protected from missiles generated from an equipment failure (UFSAR Section 3.5.1.2) .. In addition, the rod control system is fail-safe; i.e. damage to the controls would not prevent the rods from falling. However, procedural guidance .exists whenever one or more control rods fail to insert. Therefore, PSE&G believes that the safety implications of this condition were minimal.

CORRECTIVE ACTIONS:

1. The proper configuration was restored under work order 980403238 shortly after discovery. This was accomplished prior to entering Mode 2.

2. The Unit 2 sandboxes were verified properly installed.

3. The reactor reassembly procedure will be revised to ensure that the reactor vessel inspection ports are properly secured. This revision will be in place prior to the next refueling outage.

NRC FORM 366A (4-95)