05000261/LER-1977-001, :on 770124,during Normal Operations Boric Acid Transfer Pump B Tripped Due to High Pump Motor Temp Cutout. Caused by Equipment Malfunction.Pump Balance Line Cleaned & Restarted
| ML20086F047 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 02/23/1977 |
| From: | Banks H, Mcgirt J CAROLINA POWER & LIGHT CO. |
| To: | Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| LER-77-001, LER-77-1, NG-77-200, NUDOCS 8312120154 | |
| Download: ML20086F047 (3) | |
| Event date: | |
|---|---|
| Report date: | |
| 2611977001R00 - NRC Website | |
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EVENT DESCRIPTION
o l During normal operation "B" Moric Acid Transfer Pump tripped due to high pump motor l
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l temperature cut-out, l' nit was operatinn at 100% power with "A" Boric Acid fransfer l
7 il D 00 SE l Pump available. The re-circulating IIne which cools and lubricates the motor was l
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@l found plurred with partially solidified horic acid. The Ifne was cleaned, and the l
@l pump returned to normal servict:. No simila,r occurrence had occurred.
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f MAf f I Ed A VOLATON 8 I Pl cl Lu l e l u i nl Pix lx_1 (NJ I cl 310101 LNJ 7 UU 10 11 12 17 43 44 47 40 CAUSE DESCRIPTION
@ l The "B" Boric Acid Transfer Pump's re-circulating line which cools and lubricates the]
7 n9 U0 Q l motor was found plugned with partially solidified horic acid.
The line was cicaned l
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" f and the pump returned to norm 71 service after satisfactory operation.
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- 1. H. McDirt NAME:
PHONE:
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Jieport No.:
50-261/77-1 2a. Report Date: February 17, 1977 2b. Occurrence Date: January 24, 1977 3.
Facility:
H. B. Robinsor Unit No. 2, Hart sville, S. C.
29550 J3entification of Occurrence: At 0747 and 0810 hours0.00938 days <br />0.225 hours <br />0.00134 weeks <br />3.08205e-4 months <br /> on January 24, 1977, 4.
1 "b"
Boric Aci<l Transfer Punip t ripped on thermal overload and was subsequently taken out of service. This constitutes a Reportable Occurrence with Technical Specifications Paragraph 6.9.2.b.2.
5.
Conditions Prior to Occurrence:
No unusual conditions prevailed prior to the occurrence.
The plant was operating at steady state and 100% power.
"B" Boric Acid Transfer Pump was re-circulating "B" Boric Acid Tank.
6.
Description of Occurrence: At 0747 hours0.00865 days <br />0.208 hours <br />0.00124 weeks <br />2.842335e-4 months <br /> on January 24, 1977, "B" Boric Acid Transfer Putap tripped on theriaal overload while re-circulating "B" Boric Acid Tank.
Heat trace temperature indicated 155 F.
The overload was reset and the pump re-started at 0805.
A pump discharge pressure of 106# was obtained. At 0810, "B" Boric Acid Transfer Pump again tripped on thermal overload.
At 0830, "A" Boric Acid Transfer Pump was aligned to the blender and to re-circulate with the boron injection tank.
"B" Boric Acid Pump was taken out of service per OWP CVC-7.
Invest.igation revealed that the "B" pump balance line was plugged with partially. solidified boric acid. The balance line was cleaned, and "B" Boric Acid Transfer Pump was re-started at 1252.
A discharge pressure of 108#
was observed with heat tracing temperature of 180 F.
The pump operated satis-factorily and was returned to normal service.
7.
Designation of Apparent Cause of Occurrence: The apparent cause through investi-gation was that the "B" Boric Acid Transfer Pump's balance line (re-circulates to cool and lubricate the motor) was plugged with partially solidified boric acid. The loss of cooling flow across the rotor caused the pump to trip on thermal overload. The balance line was cleaned and the pump operated satisfac-torily af terwards.
8.
Analvnis of Occurrence: The failure of "B" Boric Acid Transfer Putnp was due to equipment malfunction.
Corrective action was considered adequate to pre-vent subsequent failures.
There were not any adverse effects to plant opera-tion or to public health and safety.
9.
Corrective Action
The balance line on the "B" Boric Acid Transfer Pump was cleaned and the pump re-started with satisfactory operation.
10.
Failure Data: No similar failure had occurred.
.i
l Carohna Power & Light Company L f1LE00EE IE February 23, 1977 FILE: NG-3513 (R)
SERIAL: NC-77-200 CD oy,b. '.
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Mr. Norman C. Moscicy, Director U. S. Nuclear Regulatory Commission Il.
fj Region II, Suite 818
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230 Peachtree Street, N.W.
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Atlanta, Ccorgia 30303 ms s.as f
Dear Mr. Moseley:
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- 11. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET 50-261 LICENSE NO. DPR-23 LICENSEE EVENT REPORT 77-1 In accordance with Section 6.9.2.b of the Technical Specifi-cations for the 11. B. Robinson Steam Electric Plant, Unit 2, the attached Licensee Event Ecport is submitted.
This report fulfills the requirement for a written report within thirty (30) days of a reportable occurrence and is in accordance with the format set forth in Regulatory Guide 1.16, Revision 4.
Yours very truly, fl Y
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- 11. R. -Banks Manager Nuclear Cencration WII:kd Attachment cc: Messrs. W. C. Mcdonald E. Volgenau l
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