ML19095A230
| ML19095A230 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/26/1978 |
| From: | Stallings C Virginia Electric & Power Co (VEPCO) |
| To: | Harold Denton, Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| Serial No. 269B/050578 | |
| Download: ML19095A230 (2) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND,VIR.OINIA 23261 Mr. Harold R. Denton, Director Nuclear Reactor Regulation July 26, 1978 U. S. Nuclear Regulatory Connnission Washington, D. C. 20555 Attn:
Mr. Albert Schwencer, Chief Operating Reactors Branch 1
Dear Mr. Case:
Serial No. 269B/050578 PO&M/RWC:das Docket Nos. 50-280 50-281 License Nos. DPR~32 DPR..:.37 We have completed the inspection and maintenance of Surry Unit No. 2 outside recirculation spray (ORS) pumps and a low head safety injection.* (LHSI) pump as outlined in our letter to you dated May 26, 1978.
The condition of Unit No. 2 ORS and.LHSI pumps was similar to Unit No. 1.
The LHSI pump radial bearing clearance varied from 5 to 8 mils.
The carbon bear-ings were smoothly worn and showed no signs of debris damage.
The ORS pump shafts exhibited less galling than Unit No.'.l.
The shafts were generally straight with a maximum bow of.005 inches T.I.R.
The ORS bearings exhibited wear similar to Unit No.
- l.
The minimal amount of 'bearing and shaft wear experienced on the Surry LHSI pumps is totally acceptable and along with vibration data indicates excellent pump operation.
As a result, we do not plan to pursue modifications to the LHSI pump or to des.ign a cross connect system.
The Unit No. 2 ORS shafts have been Cr plated, the colunms have been opti-cally aligned and all necessary bearings have been replaced.
Hydraulic model tests of the suction flow stability of the ORS and LHSI pump/can configuration are underway.
Final results for the ORS pump should be available by the middle of August at which time testing of the LHSI config-uration will connnence.
Inspection and optical alignment of Unit No. 2 inside recirculation spray pump was not done this outage but will be done no later than January 31; 1979.
Based on test and inspection data on the LHSI and ORS pumps we do not.feel lo.ng term testing of the LHSI or ORS pump is warranted.
Unlike the Ingersoll-Rand LHSI pumps at North Anna the Byron Jackson LHSI pumps at Surry have shown no evidence of less than excellen~ performance.
The bearing - shaft clearance has remained less than,008 inches after more than 50 ho.urs of operation.
We feel the rigid design, strict installation procedure and water injection lubrication system have ensured performance superior to the North Anna LHSI pump.
VIRGINIA ELECTRIC A!'ID POWER COMPANY TO Mr. Harold R. Denton Page 2 There is no indication of unacceptable Byron Jackson LHSI pump performance to warrant the expense of long term.testing.
We propose an inspection of the remaining LHSI pumps during Unit No; 1 and No. 2 steam generator replacement outages to confirm acceptable performance.
The Bingham-Williamette (BW) ORS pumps at Surry have undergone modifica-tions identical to the B-W ORS pumps at North Anna.
The fully instrumented 450 hour0.00521 days <br />0.125 hours <br />7.440476e-4 weeks <br />1.71225e-4 months <br /> ORS pump tests performed at North Anna clearly demonstrate that Cr plating of the shaft, substitution of bearing materials, optical alignment of the columns and suction flow stability reduces short term and long term bear-ing - shaft wear and pump vibration.
We feel this data is directly applicable to the Surry ORS pumps and a repeat test is not warranted.
We propose to inspect Unit No. 1 ORS pumps during the steam generator re-placement outage scheduled for fall of 1979. to confirm that the modifications have improved the bearing and shaft wear characteristics.
As requested in your letter of June 8, 1978, we have reviewed our practice of testing the inside recirculation spray (IRS) pumps in the dry condition.
In May 1978 an inspection was performed on a Unit No. 1 IRS pump.
This was follow-ing approximately 60 separate pump tests in the dry condition.
Inspection results were sunnnarized in LER 78~012/03L-O for Unit No. 1.
This inspection demonstrated that dry test~ng does not cause excessive wear or degradation of these pumps.
Accordingly, we see no need to modify our periodic test methods for the IRS pumps.
We believe that the LHSI, ORS and IRS pumps will operate to mitigate the quences of a LOCA.
Therefore, continued operation of Surry Units No; 1 and 2 poses no threat to the health and safety of the general public.
cc:
Mr. James P. orReilly Very truly yours,
- ~;~
- ~
C. M. Stallings Vice President - Power Supply and Production Operations