ML18152B041

LER 88-017-00:on 880606,discovered Debris in Temporary Discharge Cone Strainer & Recirculation Spray Sump Pumps. Caused by Inadequate Insp Program.Containment Sump & Pump Screen Surveillance Will Be implemented.W/880706 Ltr

ML18152B041
Person / Time
Site:	Surry
Issue date:	07/06/1988
From:	Benson D VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
88-031, 88-31, LER-88-017-01, LER-88-17-1, NUDOCS 8807130329
Download: ML18152B041 (3)

Text

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NF.C Form 388 19-83) e POW 28-06-01 U.S. NUCLEAR REGULATORY COMMISSION

\.-' APPROVED OM& NO. 3160-0104

• LICENSEE EVENT REPORT (LERI EXPIRES: 8/31/88 FACILITY NAME 111 OOCKET NUMBER 121 . I PAGE 131 TITLE 141 Surry Power Station, Unit 1 Io 15 I o Io I o I 218 IO 1 loF OI 4 Debris In Containment Sumps Due To Inadequate Inspection Program EVENT DATE 15) LER NUMBER 16) REPORT DATE 171 OTHER FACILITIES INVOLVED 18)

MONTH DAY YEAR YEAR t:t SE~~~~~~AL ti~::,~~~~ MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERIS) oIG oI 6 s s ala - oh I1 ,_ ol o o l 1 oI 6 sls THIS REPORT IS SUBll!ITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Chock on* or moro of tho follo"(ing) (11)

OPERATING MODE (91

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50.73(a)(2)(1) 50.73(1)(2)(vlll)(A) 366AJ X 50,73(1)(21(111 50,73(1)(2)(1111 LICENSEE CONTACT FOR THIS LER (12)

S0,73(1)(2)(vlll)(BI 50.73(1)(2)(xl NAME TELEPHONE NUMBER AREA CODE D. L. Benson, Station Manager 8 I O 14 3 I 5 I 71- I 3 I 1 I 814 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 CAUSE SYSTEM COMPONENT MANUFAC* MANUFAC-TURER CAUSE SYSTEM COMPONENT TURER R~~o~;:g~E !i!i!i:::::::J:!:i!J:1:1:Jii:i:!:J:iil!ii!!ii!:!:!:l!

I I I I I I I I I I I I I I I I I I I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAY YEAR EXPECTED SUBMISSION rx, YES (If yos, comploto EXPECTED SUBMISSION DATE)

DATE 1151 n IR ~ In RIR ABSTRACT (Limit to 1400 spacos, i.*., opproximotoly flftoon singlo-s,,.c* typowrittan lines/ (181 On June 6, 1988 with Units 1 & 2 in cold shutdown, following a special test run of the Unit 1 Inside Recirculation Spray (IRS) pump {EIIS-P}, foreign material was found in the temporary discharge cone strainer. As a result of this finding, an inspection of the Unit 2 Recirculation Spray pump sumps was conducted, and foreign objects were also discovered. The sump screens were inspected and various deficiencies were noted. The foreign objects were removed from the sumps, the screens were repaired and sump divider screens were installed. A containment sump and pump screen surveillance will be implemented. A similar inspection program for Unit 1 was initiated and completed. These results are being evaluated and will be submitted as a supplement to this report.

8807130329 880706 PDR ADOCK 05000280 S PDC NRC Form 389 (9-831

POW 28-06-01 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER) TJ:XT CONTINUATION

,:.i APPROVED 0MB NO. 31.50-0104 EXPIRES: 8/31 /BB t,F~Ac;:';'1;"';'LIT;;:Y;-::N:;:;A:::ME~l::;11---------------r:::oo=-=c~KE==T~N~uM~B~ER~l~1 " - - - - , - - - - - - - - - - - - . . . . - - - - - - - I 2 LER NUMBER (61 PAGE (31 Surry Power Station, Unit 1 o Is I o I o I o 1 21 a I o s Ia - o 11 I 1 - o I o oI 2 oF o14 TEXT (If more SPBCO is rBquired. use Bddition*I NRC Forrrr366A'si 1171

• 1.0 Description of the Event On June 6, 1988, with Units 1 and 2 in cold shut-down, following a special test run .of the Unit 1 Inside Recirculation Spray (IRS) pump {EIIS-P}, foreign material was found in the temporary discharge cone strainer. The material consisted of cap screws, a -

swagelock cap, nuts, weld wire and other objects. As a res*ult of this finding and the imminent return to power by Unit 2, an inspection of the Unit 2 Recirculation Spray (RS) pump sumps was conducted.

This area includes the pump suctions for the IRSPs, the Outside Recirculation Spray (ORS) pumps {EIIS-P} and the Low Head Safety Injection (LHSI) pumps {EIIS-P}.

This inspection utilized fiber optics and included removal Of foreign objects. The foreign objects removed included nuts, bolts, wire, metal and wood pieces, and other material.

Multiple screens are installed to prevent foreign objects from entering the above pump suctions. These screens were inspected. Various deficiencies were noted which included gaps in the cylindrical screens surrounding the individual pump suctions, a missing divider screen which separates the 'A' and 'B' trains of these pumps, and various missing fasteners for the screen sections. A similar inspection program for unit 1 was initiated and completed. The completed unit 1 inspection results are being evaluated and will be submitted-as a supplement to this report.

2.0 Safety Consequences and Implications An engineering review of the "as found" condition of the Unit 2 Recirculation Spray systems and LHSI systems was conducted. It was found that the fin~ mesh cylindrical screens were loosely fastened with small gaps between some sections. The fine mesh cylindrical screens are intended as a backup to the roughing and fine mesh screen arrangement! The roughing and fine mesh screens also had minor gaps. The "as found" screen arrangement provides an extremely tortuous path for foreign object introduction into the suction piping of the RS and LHSI lines. Therefore, a remote possibility of foreign object introduction did exist.

NRC FORM 366A *u.s. GPO, 1988-520-589,00070 (9,831

NRC Form 366A POW 28-06-01 U.S. NUCLEAR REGULATORY COMMISSION

{a-s~J LICENSEE EVENT REPORT (LERI T!:XT CONTINUATION APPROVED 0MB NO. 3150-0104 EXPIRES: 8/31/88 FACILITY NAME 11) DOCKET NUMBER 12) LER NUMBER 16) PAGE (3)

Surry Power Station, Unit 1 0 15 I O I O I o I 21 s lo s I s - o I 1 I 7 - o Io o I 3 OF o Iu TEXT /If more space is required, use edditionel NRC Form 368A 's/ ( t7)

The review also concluded that a small probability existed for one of the foreign objects, a swagelock pipe fitting discovered in the LHSI suction piping, to migrate to one of three parallel venturi flow limiting deviqes and block LHSI to one loop. However, an analysis of the geometry of the venturi restrictions and that of the pipe fitting found the probability of a -

flow blockage event to be too small to be considered a credible event. The study concluded that the RS and LHSI systems would function as designed. Therefore, the health and safety of the public were not affected.

A similar engineering review of the inspection of unit 1 will be conducted.

3.0 Cause

_ The debris in the *Rs and LHSI sumps and suction piping resulted from inadequate sump well cleaning and screen inspection in the past. Due to the inadequacy of sump cleaning and inspection, foreign objects were allowed to accumulate in the sump wells.

The gaps in the cylindrical pump suction well filter screens appear to be a design deficiency which has existed since initial installation.

Since there had been no established sump screen inspection program, it is unknown when and why the divider screens were removed without replacement or if they were initially installed.

4.0 Immediate Corrective Action(s)

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

5.0 Additional Corrective Action(s)

The foreign objects were removed from the sumps.

The cylindrical screens on which gaps were discovered were repaired. Sump divider screens were fabricated and installed.

NRC FORM 366A *u.s. GPO, 1988-520-589,00070 (9-83)