ML20069B108
| ML20069B108 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 12/18/1981 |
| From: | Leasburg R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Clark R, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 675, NUDOCS 8112240107 | |
| Download: ML20069B108 (2) | |
Text
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~ VIRGINIA ELECTRIC AND POWER COMPANY' Ricnwown, VimonwsA 20261 R.H.LEANSUMo December 18, 1981-Vaca Poseinant Nuca. man Oramarrons Mr. Harold R.' Denton, Director Serial No. 675 Office of Nuclear Beactor Regulation NO/RMP:acm Attn: Mr. Robert A. Clark, Chief Docket Nos. 50-338
_ Operating Beactors Branch No. 3 License Nos. NPF-4 U.' S. Nuclear Regulatory Otxmtission Washington, D. C. 20555 Gentlenen:
Pursuant to North Anna Power Station Unit 1 'Ibchnical Specification 4.4.10.1, the Peactor Coolant System flow splitters were ultrasonically inspected during October 1981.
Ir, accordance with the Safety Evaluation for Amendment No.16, the attached report of those inspection results is'being sutxnitted for review.-
'Very truly yours, f
k.Icasburg R.
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Enclosure Serial No. 675 Results of Ultrasonic Examination of Unit 1 Feactor Coolant Punp Flow Splitters Conducted October 1981 On October 12 thru 14, 1981 the Unit I flow splitter welds were ultrasonically _
examined in accordance with approved procedures.
Several ultrasonic indications present during the April 1979 and February 1981 examinations were observed to have increased in length.
'Ihe changes in the indications (February 1981 vs. October 1981) for each flow splitter are sunrnrized below.
"A" Icop (Containment Wall Side): 'Ihe total length of indications increased frun 23 inches to 34 inches. The largest increase (6.5 inches) occurred where two indications had jolned. 'Ihe trailing edge of this indication was 11 inches frm the trailing edge of the flow splitter plate. 'Ihere were no new indications.
"A" loop (Reactor Vessel Side): The total length of indications increased from 4 inches to 10 inches. The increase included a new indication of 2 inches located 59 inches fr m the trailing edge of the flow splitter.
"B" Icop (Containment Wall Side): The total length of indications increased frun 2" to 4".
There were no new indications.
"B" Icop (Feactor Vessel Side): The total length of indications increased frm 0.5 inches to 9.5 inches. 'Ihe increase included a new indication of 2.5 inches located 31 inches fran the trailing edge of the flow splitter.
"C" Icop (Containment Wall Side): The total length of indications increased by 1 inch. 'Ihere were no new indications.
"C" Icop (Reactor Vessel Side): There was no change in the length of inClcations.
The longest indication is approximately 12 inches and is located in A Icop (Containment Wall Side).
The trailing edge of this indication is located approximately 11 inches frm the trailing edge of the flow splitter.
As previously reported for all indications, the depth of the reflector was beyond the cast elbow and in the splitter plate itself. There is ro evidence of degradation of the elbow pressure boundary.
As in previous inspections, there were no indications on either the leading or trailing edges of any of the flow splitters.
I The Safety Evaluation of Peactor Coolant Punp Suction Elbow Splitter North Anna 1 dated April 15, 1979 evaluated the partial / total failure of the flow splitter - plate.
'Ihis safety evaluation gave justification for continued operation and is still applicable.
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