ML18153C260

LER 89-003-01:on 890126,damaged Insulation Noted on motor- Operated Feeder Cables Located on Inside Recirculation Spray Pump Motor.Caused by Improper Lug Crimping & Scratches on Cable.New Field Cables installed.W/900621 Ltr

ML18153C260
Person / Time
Site:	Surry
Issue date:	06/21/1990
From:	Kansler M VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
90-323, LER-89-003, LER-89-3, NUDOCS 9006250392
Download: ML18153C260 (7)

Text

VIRGINIA ELECTRIC AND POWER COMPANY Surry Power Station P.O. Box 315 Surry, Virginia 23883 June 21, 1990 U.S. Nuclear Regulatory Commission Serial No.: 90-323 Document Control Desk Docket No.: 50-280 Washington, D.C. 20555 50-281 License No. : DPR-32 DPR-37 Gentlemen:

Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following updated Licensee Event Report for Units 1 and 2.

REPORT NUMBER 89-003-01 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be reviewed by Corporate Nuclear Safety.

Very truly yours, tfanlrr Station Manager Enclosure cc: Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323

Updated Report POW 28-06-01 NIICFerM . . U.S. NUCLEAII IIEGULATORY COMMISSION Ct-all A,,11ovED DMI NO. :nlilMnCN LICENSEE EVENT REPORT (LER) EX,tJIEI: 1/:11111 FACILITY NAME 111 DOCICET NUMIEII 121 I 'A<iE 1;11 Surry Power Station, Units 1 and 2 I 0 I 5 I O IO I O ,2 I 8 IO I 1 l OFI O I 6 TITLE I" Degraded IRSP Motor Power Feeder Cables and Motor Leads EVENT DATE 151 LER NUMBER 161 , REPORT DATE 171 OTHER FACILITIES INVOLVED Ill FACILITY NAMEI DOCICET NUMIEA1Sl 011 21 6 8 9 s 19 - o 10 I3 - oJ 1 oI6 211 o 1 s 1o 1.0 1 0 1 I I Dl'ERATING THIS REPORT JS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: IC**c* ono 0 , ,,.0 ,0 01 *** <ouow,n/1/ 1111 POWIII I t---M_o_D_E'Tcll_,_ _L-N4-~ 2D.4021bl 20 . .clll*JIIJCJJ 20.4051*1 IIO.Jllcll11 LZ.

. 50.73CoH211iwl II0.731all2llwl 73.711bl n.7Ucl LIVIIOIIL O 10 I O'--

1,:,:,:~~-.i,.....J.-L-.J-~ 20 *.cllloll111il 20.40l(oJ11JIHII IIO ** (cll21 II0.73lol121111 --- II0.731oll21Cril II0.731oll2llwillllAI DTHEII (S,,.,Hy in Ablnct below *"'1 in 366,f,/

r..,. NRC Form

".j:fi******~

NAME 20.40llalCUCJ,I 20 ..clllall111*1 I0.731all211WI

• I0.7311ll211Hll LICENSEE CONTACT FOR THIS LEII 1121 I0.7Jlall211wlllllll eo.131a11211.:,

TELEPHONE NUMIIER H. R. Kansler, Statibn Manager AREA CODE 8 IO I 4 3 I 51 7 1 13 1 1 18 I 4 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIIED IN THII RE,ORT 1131 MANUFAC MANUFAC*

CAUSE SYSTEM COMPONENT TURER COMPONENT TURER X I C1I31L C 15 18 1 8 I I I I 1* I X I JH 10 GJO 18 I 0 I I I I I I IU'l'LEMENTAL IIE,OIIT EXl'ECTl!D 1141 MONTH DAY YEA.II l!X,ECTED hi NO IUIIMISSION DATE 1151 I I I On January 20, 1989, Unit 1 and 2 were in cold shutdown. During the installation of the Unit 1 "B" Inside Recirculation Spray Pump (IRSP) motor, damage to the insulation of one of the motor power feeder cables was observed. The damaged area was located inside the flexible conduit connecting the motor leads at the junction box to the rigid conduit containing the field run cable leads. An inspection was conducted on the Unit 1 "A" and Unit 2 "A" and motors feeder cables and additional damage to the braided outer "B"I jacket of the feeder cable was noted with some minor flaws and scratches on the insulation. On January 26, 1989, a report on these findings was made to the NRC. Subsequent inspections of the pump motors identified additional concerns related to motor lead sealing areas and lug crimping which were evaluated and corrected by the manufacturer. On January 29, a 10CFRS0.72 four hour report was made to the NRC identifying the condition noted in the pump's motor lead sealing area and deficiencies in the motor lead lugs resulting in I the Unit 1 "B" motor and the Unit 2 "B" motor being evaluated as I

i having been inoperable.

I NIIC Forn, JIG 19-831

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104

- EXPIRES: 4/30/92 LICENSEE EV. REPORT (LER) - -ATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2)

LER NUMBER (6) PAGE (3)

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

NUMBER

::::::::: NUMBER Surry Power Station, Units 1 and 2 TEXT (ff more space is required, uStl additional NRC Form 3li!iA 's/ (171 1.0 Description of the Event On January 20, 1989, Units 1 and 2 were in cold shutdown (CSD). During the installation of the Unit 1

~'B" Inside Recirculation Spray Pump (IRSP) motor (EIIS-BE) following maintenance on the pump, damage to the insulation of one of the motor power feeder cables (EIIS-CBLS) was observed. The insulation damage w9 s such that the conductor was visible. The damaged area was located inside the flexible conduit connecting the motor leads at the junction box to the rigid conduit containing the field run cable leads. As a result of this observation, a complete inspection of the Unit 1 "B" IRSP motor feeder cables was initiated. The inspection included the examination of cab,les from the flexible conduit to the containment penetration area, including removal of the cable from the rigid conduit for examination.

The power cable is a triplex cable with 4/0 copper conductors covered with a silicon rubber*insulation and a glass braid jacket. Based on the cable damage on the Unit 1 "B" IRSP motor, an inspection of the three other IRSP motors in Unit 1 and 2 was conducted.

The inspection of the power feeds to the Unit 1 "A" IRSP motor and Unit 2 "A" and "B" pump motors revealed damage to the braided outer jacket of their cables in the area of the flexible conduit. In some cases, minor flaws and scratches were noted on the cable, but they did not breach the insulation. On January 26, 1989, a 10CFRS0.72 four hour report on these findings was made to the Nuclear Regulatory Commission (NRC).

Another area of concern identified during subsequent inspections was in the motor leads sealing area.

There are six motor leads, two per phase, exiting the motor housing through the sealing area. These leads are insulated with Kapton insulation covered with a glass tape (for mechanical protection from wearing against the sealing material) and covered with a varnish coating. The Kapton insulation of the motor leads on the Unit 2 "B" IRSP was damaged. The pump manufacturer indicated that the motor leads on the other pumps were damaged to the point where the glass NRC Form 366A (6-89)

NRC FORM 366A . *U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 E* ATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVE' REPORT (LERI INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (11 DOCKET NUMBER (21 LER NUMBER (6) PAGE (31 Surry Power Station, Units 1 and 2 0 IS IO IO IO I 21 s I O 8 I 9 - 01 013 - 0 I 1 013 OF O 16 TEXT (ff more spaco is required, u/ltl additional NRC Form 366A 'sl 1171 tape had frayed; however, the Kapton insulation remained intact.

Lugs are placed on the end of the motor leads and field cables and are bolted together with a r

heat-shrink insulating material covering. the connection. A lug on one of the motor leads for the Unit 2 "B II pump came off. when the heat-shrink insulation was removed.

Subsequent examination of the Unit 1 "A" IRSP and the Unit 2 "A" IRSP determined that the condition of lug indent crimps on these motor terminations did not meet current industry standards and could result in indeterminate strength and conductivity for the lug*

connection.

On January 29, 1989, a 10CFRS0.72 four hour report was made to the NRC identifying the condition noted in the pump's motor lead sealing area and deficiencies in the motor lead lugs.

2.0 Safety Consequences and Implications The Recirculation Spray (RS) system consists of four independent trains, each train containing a pump, (two pumps inside containment and two pumps outside

• containment), 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 is 50% capacity.

An engineering evaluation was conducted following the receipt of the "as found" condition of the motor leads from the motor manufacturer. The Unit 1 "B" IRSP was considered inoperable due to its damaged feeder cable.

The Unit 2 "B" IRSP was considered inoperable due to the damaged insulation on the motor lead and the lug that became detached. The effects of the improperly crimped lugs on operability of the Unit 1 and 2 "A" NRC Form 366A (6-891

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104

• EXPIRES: 4/30/92

-ATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVE. REPORT (LER) INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530). U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON. DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

Surry Power Station, Units 1 and 2 TEXT (ff more sptJca is mquiffJd, u~ additional NRC Form 3S6A's/ (17)

IRSPs could not be determined. However, given that pumps had operated satisfactorily during past periodic testing, which demonstrated that the lugs could carry the required current, operability of the pumps would most likely not have been affected. Consequently, one train of IRSPs remained unaffected. In addition, the effect of losing both IRS pumps was estimated using an analysis performed in June, 19.85 for Surry Unit 2.

Based upon this estimate for a worst case accident scenario (one train of containment spray operating (EIIS-BE), one train of outside recirculation spray (ORS) operating and no IRS pumps operable), the 10 CFR 100 off site dose limits would not be exceeded; however, the main control room GDC-19 thyroid dose limit could be exceeded.

Therefore, the health and safety of the public were not affected.

3.0 Cause The damage to the field cable was determined to be mechanical in nature with no signs of aging or thermal degradation. It was most likely caused by the handling of the flex conduit and not from the initial cable installation. This is further supported by the fact that the exposed conductor on the Unit 1 "B 11 pump was bright, indicating recent damage.

The cause of the separation of the lug from the conductor was determined to be due to improper crimping of the lug.

4.0 Immediate Corrective Action(s)

No immediate actions were required since both units were in cold shutdown.

5.0 Additional Corrective Action(s)

Following the observation of the damage to the Unit 1 "B" pump, the following actions were performed:

I NRC Form 366A (6-891

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 E ATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE E V . REPORT (LERI INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1"HE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE

'I OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (61 PAGE (3)

Surry Power Station, Units 1 and 2 01s101010121s,os19 - 01013 _o,101s oF 016 TEXT (If more space is required, use addftional NRC Form 366A 's/ (17)

Cables to the other IRSP motors were removed and inspected to determine if similar damage existed inside the rigid conduit. No additional damage was identified.

New field cables were installed on the IRSPs.

Cable inspections were expanded to inspect for similar damage in other silicon rubber cable applications and no other similar damage was noted.

Cables suspected of having cracks through the insulation were tested on site for adequate resistance. Resistance values measured were satisfactory.

Motor leads on the IRSPs were extended and their insulation reconstructed.

Inspections were performed on other motors that have motor lead interface fabrication details similar to the IRSPs. These motors were checked for lugging and termination detail adequacy and for cable damage inside the flex conduit. Although discrepancies similar to the ones identified on the IRSP motor lug terminations were noted on the additional motors checked, these discrepancies were not significant enough to affect component operability. All noted discrepancies were corrected.

6.0 Action(s) Taken to Prevent Recurrence A special task team was formed to determine the cause of the damage to the IRSPs, and a report was prepared.

In addition to the actions described above, the following corrective actions, which address the recommended corrective actions for the root cause identified in the task team's report, were taken:

- The Sm::ry Power Station document governing specification on motor terminations has been revised to provide better detail on motor.

terminations.

NRC Form 366A (6-89)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104

• EXPIRES: 4/30/92

• E-TED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVE' REPORT (LERI INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE l' OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

SEQUENTIAL ;

;

;

;

;

; REVISION YEAR  :;:;:;:;:;: NUMBER  ;:;:;:;:;: NUMBER Surry Power Station, Units 1 and 2 o 1s Io Io Io I 2 f8 I o s 19 OF O 16 TEXT /If mom space is requlmd, ust1 additions/ NRC Form 3S6A's/ (17)

- Electrical maintenance procedures for safety related motors required for safe shutdown have been revised to standardize electrical workmanship details for heat shrink and lug installation.

Engineering is developing termination instructions for the remaining safety related motors to support maintenance during which the motors are determinated.

- Training has been provided to the appropriate personnel on the proper performance and inspections of these terminations.

7.0 Similar Events None.

8.0 Manufacturer/Model Number(s)

Cable - Continental 4/0 Tri Plex Silicone Rubber Insulated Glass Braid Covered.

Motors - General Electric/5K6319XJ1D, 300 HP 1780RPM Vertical.

NRC Form 366A (6-891