ML20023E067

LER 83-006/03L-0:on 830427,during Testing of Spare Pump Installed to Replace Svc Water Pump A,Pump Tripped on Overcurrent.Apparently Caused by Internal Binding of Shaft as Result of Debris in Impeller assembly.W/830526 Ltr

ML20023E067
Person / Time
Site:	Robinson
Issue date:	05/26/1983
From:	Cox H, Starkey R CAROLINA POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
LER-83-006-03L-02, LER-83-6-3L-2, RSEP-83-672, NUDOCS 8306070161
Download: ML20023E067 (4)

Text

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NRC FORM 366 U. S. NUCLEAR REGULATORY COMMISSION (7-77)

, LICENSEE EVENT REPORT CONTMOL BLOCK: l l l l  ! l ) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 L l0 l1l 7 8 9 l Sl LICENSEE Cl HICODE Bl Rl 2l@l 0l 0l -l 0l 14 15 0l 0l 0l 0l -l 0l 0lhl 4l 1l LICENSE NUMBER 26 26 Il 1l 1l@l 67 CAT LICENSE TYPE Jo l

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7 8 61 60 EVENT DATE 74 7b REPORT DATE EVENT DESCRIPTION AND P5408 ABLE CONSEQUENCES h 10121 1 On April 27. 1983 at 0915 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.481575e-4 months <br />. with the uni t at ROY nnwer "A" hrvice tJn t o r (RU)l IO lal l pump was removed from service for normal preventative maintennnce. Sneci f f en t ly. "A'l i

[ O l41 l SW pump was being replaced with a spare pump. During testing, the rehnfit pumn l 10151 1 tripped on over-current which is believed to have been caused by internal binding l lo Is l l of the pump shaft. This event resulted in operation in a degraded mode permitted l l0 l7l l by a limiting Condition for operation as defined by Technical Specification 3.3.4.2 l and is reported pursuant to 6.9.2.b.2. The redundant SW pumps were operable, thus, 10181 l there was no threat to the public health and safety. I C DE CODE SUBC E COMPONENT CODE SUBC dE S E 7

O 9 8

l Wl Al h W h [B_j h l PI d Ml PI Xl XIh d h d h 9 10 11 12 13 18 19 20

_ SEQUENTIAL OCCURRENCE REPORT REVISION LE R RO EVENT YEAR REPORT NO. CODE TYPE NO.

O ,agg I81 31 1-1 1 01 d 61 [f_] I 01 31 L2J 1_] Lo]

_ 21 22 23 24 26 27 28 29 30 31 32 KEN AC P ON PLANT ME D HOURS S8 IT FOR B. SUPPL 1 R MAN FACTURER IAl@[B_j@ l d@ l362l@ l 01 0l Ol Ol l Yl h (_Nj h lA l h I44 JI Il 0] 5l47 @

33 34 3b 3/ 40 41 42 43 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i 11 l 0 l l The original "A" SW pump was reinstalled, tested, and returned to service at 1100 1 3 i l hours on April 28, 1983. The spare pump was returned to the vendor for inspection I

, , l and repair. Feilure of this pump is believed to be the result of debris in the I

, i3 g l impeller / pump casing assembly. The spare pump was installed during the current l Steam Generator outage under vendor supervision, and "A" SW pump was returned to I i 14 I l sa tis fact ory se rvic e . I 7 8 9 80 ST S  % PNVER oTHER STATUS DIS O Y DISCOVERY DESCRIPTION l_1_lf_j Wh l 0] BlOlh! N/A I BI lhl Preventative Maintennnce l ACTIVITY CO TENT RELEASED OF EELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE l1 l6 I h I Zl@l N/A l l N/A I i 7 8 9 10 11 44 45 80 PERSONNEL EXPOSURES NUVBER TYPE DESCRIPTION i > 10101 O l@Lzj@l N/A I PERSONNEtINJU IES NUMBER DESCRIPTION 1 3 l O l 010l@l12 N/A l 7 8 9 11 80 LOSS OF OR DAMAGE TO FACILiTV TYPE DESCRIPTION y W@l N/A l 7 8 9 10 80 ISSUED PUBLICITY DESCRIPTIONU 5 8306070161 830526 NRC USE ONLY LN_jhl PDR ADOCK 05000261 6 2 O S PDR I IIIIIIIIIIII! A 7 8 9 10 68 69 g g % 80 5 NAME OF PREPARER Owa d T. h PHONE

(803) 383-4524 //; E

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,  % r O Carolina Power & Light Company g **

H. B. ROBINSON STEAM ELECTRIC PLANT [9 h

Post Office Eox 790 00 Hartsville, South Carolina 29550 .- M g 9G MAY 261983 Robinson File No: 13510C Serial: RSEP/83-672 1

Mr. James P. O'Reilly Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 LICENSE NO. DPR-23 LICENSEE EVENT REPORT 83-006

Dear Mr. O'Reilly:

In accordance with Section 6.9.2 of the Technical Specifications for the H. B. Robinson Steam Electric Plant, Unit 2, the enclosed Licensee Event Report is submitted. This report fulfills the requirements for a written report within thirty (30) days of a reportable occurrence and is in accordance with the format set forth in NUREG-0161, July,1977.

Very truly yours, hI /t in G R. B. Starkey, J .

General Manager H. B. Robinson SEG Plant HTC:FMG:JMC:CWC/th Enclosure cc: R. C. DeYoung (30)

R. A. Hartfield (3)

'bFFICI re w ,b

'. SUPPLEMENTAL INFORMATION FOR LER-83-006 I. Cause DTscription and Analysis, On April 27,1983, at 0915 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.481575e-4 months <br />, with the unit at 80% power, "A" Service Water (SW) pump was removed form service for normal pre-ventative maintenance. This maintenance consisted of replacing the pump with a spare pump. Testing of the pump, af ter installation, resulted in an over-current trip which is believed to be the result of internal binding of the rebuilt pump.

Investigation of this event revealed that the pump shaft could not be lif ted the proper amount when the pump was installed which resulted in the impellers rubbing the pump bowls. Several unsuccessful attempts were made to raise the pump shaf t into the proper position.

After these attempts failed, the spare pump was replaced with the original pump.

This event resulted in operation in a degraded mode permitted by a limiting condition for operation as defined by Technical Specification 3.3.4.2 and is reported pursuant to 6.9.2.b.2. It should be noted that due to an increase in Steam Generator primary to secondary leakage, an orderly Plant shutdown was initiated at 0842 hours0.00975 days <br />0.234 hours <br />0.00139 weeks <br />3.20381e-4 months <br /> on April 28,1983. As described in the H. B. Robinson Final Safety Analysis, two SW pumps will supply the required cooling water for accident conditions. Therefo re, there was no threat to the public health and safety.

II. Corrective Actions The original SW pump was reinstalled, tested, and returned to service at 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br /> on April 28, 1983. The rebuilt pump was returned to the vendor for inspection and repair.

III. Corrective Action to Prevent Recurrence As stated above, the spare pump was returned to the vendor for in-s pect ion. Additionally, a Plant engineer was present at the vendor's facility during the pump inspection. No apparent cause could be determined for the inability to properly position the pump shaf t during installation. Inspection of the pump impellers and bowls revealed evidence of rubbing but no significant damage. It is believed that, during shipping and handling, a soft material such as wood, was lodged between the back of the impeller and the top of the pump bowl, thus, preventing proper positioning of the shaf t.

However, no evidence of this could be found during the inspection.

It should be noted that the other three SW pumps br.d previously been satisfactorily replaced with spare pumps.

o .,

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- Page 2 Additionally, the pump installation instructions were reviewed and found adequate with respect to pump coupling, alignment, and shaft lift requirements. The spare pump was returned to the Plant site and installed during the current Steam Generator outage under the supervision of a vendor representative. No difficulties were encountered during installation; however, on May 21, 1983, during pump testing, the pump again tripped on over-current. The motor was checked electrically and found acceptable. A check of the pump shaft revealed a 0.060 inch drop in the as-left shaft lift.

No cause has been determined for this decrease in lif t. The lift was readjusted with extra clearance applied to compensate for additional lif t decrease during pump operation. "A" SW pump was then tested, using pump discharge pressure and motor current to verify adequate flow, and returned to service. As a result of this last event , the need for additional procedural instructions con-corning shaf t lif t clearance is being reviewed, and any revisions deemed necessary will be completed by December 1,1983. No further corrective action is considered necessary.

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