ML18153B542

LER 88-024-00:on 881007,damage to Internal Components & Other Discrepancies During Disassembly of Inside Recirculation Spray Pumps a & B Noted.Cause Undetermined. Foreign Matl Removed.Repair of Pumps initiated.W/881104 Ltr

ML18153B542
Person / Time
Site:	Surry
Issue date:	11/04/1988
From:	Benson D VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
88-059, 88-59, LER-88-024-01, LER-88-24-1, NUDOCS 8811160395
Download: ML18153B542 (5)

Text

POW 28-06-01-01*

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I\IRC "r:orm 386 U.S. NUCLEAR REGULATORY COMMISSION*

(9-83)

APPROVED 0MB. NO. 31~104 EXPIRES: 8/31/88

• LICENSEE EVENT REPORT (LERI FACILITY NAME (1) DOCKET NUMBER (2) I PAGE 131 TITLE (4)

Surry Power Station, Un it 2 Io I 5 .1 o I o I o I 21 8 11 1 loF O I 4 11A 11 and "B" Inside Recirculation Spray Pump Found With Internal Damages EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR  :{t SE~~~~r~AL ti ~5i~~~ MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER(S) 1 I I cl 7 a a aIa ~ o I2 I4 - o Io 111 *01 4 s J s*

THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Chsck on* or mors of th* follo"(ing/ (11)

OPERATING

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POWER LEVEL

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OTHER (Spaclfy in Abstract lilil= ::::::::: -

60.73(1)(Z)(il 60,73(1)(Z)(ii) 60.73(1)(Z)(liil 50,73(1)(Z)(vlill(Al.

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b1Jlow and in Text, NRC Form*

366A}

LICENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NU.MBER AREA CODE D, L. Benson, Station Manager 8 I 01 4 3 15 I 71 -t 31 1 18 I 4 COMPLETE ONE LINE FOR EACK COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 CAUSE SYSTEM COMPONENT MANUFAC- MANUFAC-TURER TURER Y RI i= I I IP R I? I h I 0 y I I I I I I I Y RI i= I I IP R 17 I n Io y I I -I I I I I SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAY YEA.R EXPECTED n ~

SUBMISSION DATE (151 YES (If yss, comp/st* EXPECTED SUBMISSION DATE/ NO I I I ABSTRACT (Limit to 1400 spaces, i.e., approximately flftBtm single-space typewritten lines) (161 On October 5 and 6, 1988 with Unit 2 at Cold Shutdown, _

damage to internal components and other discrepancies were noted during the disassembly of the "A" and "B" Inside Recirculation Spray pumps. In addition, pieces of pump components and other small foreign objects were found in the "B" pump's sump. A preliminary engineering evaluation determined that the pumps were capable of starting and providing flow and pressure, but the long term operability of the pumps could not be established.

The exact cause of the pump component failures has not been determined. The foreign material was removed from the sump and the repair of the pumps was initiated. An investigation is in progress to determine the exact cause of the pump component failures. A Technical Specification (T.S.) change has been initiated to change the present pump testing frequency. In addition, a full flow test will be performed each refueling and an inspection and overhaul will be performed at a five year interval.

8811160395 881104

~DR ADOCK 05000281 PNU NRC Form 386 (9-831

POW 28-06-01-01 NRC For,z, 366A U.S. NUCLEAR REGULATORY COMMISSION 19-831 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED 0MB NO. 3150-0104 EXPIRES: 8/31 /88 FACILITY NAME 11) DOCKET NUMBER 121 LEA NUMBER 161 PAGE 13)

YEAR :::::::::;: SEQUENTIAL ;:;:::::::: REVISION

NUMBER  :::::::::: NUMBER

. Surry Power Station, Unit 2 o 1s Io Io Io I 21 a I 1 a I a-. o I 21 4 - o lo o I 2 oF o 14 TEXT (If mom space is n,quil'8d, US8 additional NRC Form 3S6A's/ 1171 1.0 Description of the Event On October 5, i988 with Unit 2 at Cold Shutdown (CSD), during the disassembly of the "B" Inside .

Recirculation Spray (IRS) pump (2-RS-P-lB) {EIIS-BE-P},

it was noted that a pump guide*bearing was damaged and a shaft sleeve bearing was missing. In addition, the pump impeller vane tips were damaged and other minor discrepancies were noted.

A*subsequent inspection of the pump suction well in the containment sump revealed pieces of shattered shaft sleeve and other small foreign metal objects.

On October 6, during the disassembly of the "A" IRS pump (2-RS-P-lA), it was noted that the first stage casing lower wear ring had sheared its retaining pins and had rotated two inches in the casing.

A preliminary engineering evaluation determined that the pumps were capable of starting and providing flow and pressure. However, the long term operability of the pumps could not be established and a four hour non emergency report was made to the Nuclear Regulatory Commission on October 7, per the requirements of 10CFRS0.72. This report is being submitted per the requirements of 10CFRS0.73.

2.0 Safety Consequences and Implications The Recirculation Spray (RS) system consists of four independent trains, each containing a pump, a heat exchanger, and a discharge spray ring. The RS system is used in conjunction with the containment spray system .following a design basis accident. It provides the necessary cooling and depressurization of the containment and is capable of maintaining the containment pressure below atmospheric for an extended period. Each of the four trains of the RS system are 50% capacity.

An evaluation of the pumps' operability was performed by the pump man~facturer. It was concluded that even with the degraded condition of the pumps, they still were capable of producing a pressure and flow. However, the effects on long term operability of the pumps could not be determined.

• L1.S. GPO: 1986-520-56:J t)0070 NAC FORM 366A 19-83;

NAC Form'>>eA

• (9-831 e

LICENSEE EVENT REPORT (LERI TEXT CONTINUATION

-- POW 28-06-01-01 U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3150-0104 EXPIRES: 8/31 /88 FACILITY NAME (1 I DOCKET. NUMBER 121 LER NUMBER (61 PAGE 131 Surry Power Station, Unit 2 0 I5 IO IO IO I 21 s I 1 81 8 - 0 I 21 . 4 - 0 IO OI 3 OF OI 4 TEXT ( I ( , - _ la _ _, , _ ~ N R C FotmBA'r) 1171 2.0 (Continued)

The effect of losing both unit 2 IRS pumps was estimated using an analysis performed in June, 1985 for Surry unit 2. The study concluded that for a worst case accident scenario (one train of containment spray

{EI!S-BE}, one train outside Recirculation Spray (ORS),

and no IRS pumps), the 10CFRlOO offsite dose limits would not be exceeded; however, the main .control room GDC-19 thyroid dose limit could be exceeded.

3.0 Cause The exact cause of the pump component failures has not been determined.

The damage to the impellers has been attributed to pump parts and other foreign objects passi~g through the purr~ during operation.

4.0 Immediate Corrective Action(s)

Since the unit was in cold shutdown condition at the time of the event, no immediate corrective actions were required.

5.0 Additional Corrective Action(s)

The foreign material was removed from the sump ano.

the repair of the pumps was initiated.

6.0 Action(s) Taken to Prevent Recurrence An investigation is in progress to determine the exact cause of the pump component failures. A Technical Specification (T.S.) change has been initiated to change the present monthly surveillance test (dry pump run) to a quarterly interval. In addition, a full flow test will be performed each refueling and an inspection ano. overhaul will be performed at a five year interval.

NRC FORM 366A

• U.S GP0:1966*0*624*536/455 (9-831

POW 28-06-01-01

• • NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (9-83)

LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVED 0MB NO. 3150---0104 EXPIRES: B/31/88 FACILITY NAME (1) DOCKET NUMBER (21 LER NUMBER (61 PAGE (31 Surry Power Station, Unit 2 05000 2

-7.0 Similar Events As reported in Unit 2 LER 88~017, foreign debris was discovered in the Unit 2 IRS pump sump *and all material was removed at that time. The pumps have been operated several times since, and it is believed that the debris discovered during the October 5 and 6 inspection had been .trapped in the pump suction bowls and consequently, had fallen out of the pump bowls following their operation.

8.0 Manufacturer/Model Numbers Bingham-Willamette/10 X 18B VCR 2 stage.

NRC FORM 366A

• U.S.GP0:1986-0-624-5_38/455 (9-831

i VIRGINIA ELECTRIC AND POWER COMPANY Surry Pow.r Station P. 0. Box 316 Surry, Virginia 23883 November 4, 1988 U.S. Nuclear Regulatory Commission Serial No.: 88-059 Document Control Desk Docket No.: 50-281 016 Phillips Building Licensee No.: DPR-37 Washington, D.C. 20555 Gentlemen:

Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Surry Unit 2.

REPORT NUMBER 88-024-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be reviewed by Safety.Evaluation and Control.

Very truly yours,

<:* r0 r*,

(_~, ' _j' '<.-.}- - -- . - '

C ~,

David L. Benson Station Manager Enclosure cc: Dr. J. Nelson Grace Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323