ML20062H604
| ML20062H604 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 11/29/1990 |
| From: | Taylor D COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-88-008, IEB-88-8, NUDOCS 9012050156 | |
| Download: ML20062H604 (2) | |
Text
[/%} 1400 Opus Plac3 Common :ealth Edistn
( v"J Downers Grove, Illinois 60515 November 29, 1990 U.S. Nuclear Regulatory Commission Attn: Document Control Desk l
Washington, D.C.
20555 Subj ec';:
Byron Station Units 1 and 2 Supplemental Response to NRC Bulletin 88-08, Supplement 3 NRC Docket Nos. 50-454/455
Reference:
(a) NRC Bulletin 88-08, Stpplement 3, dated April 11, 1989.
(h) H. Richter letter to U.S. NRC, dated July 17, 1989.
(c) M. Richter letter to U.S. NRC, dated November 27, 1989.
Dear Sir:
Reference described an event at a foreign reacter facility (Genkai) which rais ew concerns on thermal stratification in unisolable piping connected ti Reactor Coolant System (RCS).
The event in Reference (a) occurred due tt valve leakage phenomenon which was not previously considered in NRC Bulletin 88-08 (or Supplements I and 2).
Reference (a) requested that the Actions in NRC Bulletin 88-08 (Bulletin) be addressed.
As reported in Reference (b), Commonwealth Edison (Edison) identified two (2) lines associated with the Residual Heat Removal (RHR) Syst.em per unit at Byron Station which may be susceptible to cyclic stratification due to the valve leakage phenomenon desciIbed in Reference (a).
To address Bulletin Actions 2 and 3 for Byron Station, Edison indicated that an evaluation was being performed which would supply the critical locations on the susceptible i
piping for inspection purposes, and the frequency of future inspections to ensure piping integrity.
Reference (c) provided the results of that evaluation for Byron Station.
Reference (c) also indicated Byron Station would be performing non-destructive examinations on tne' susceptible RHR suction lines at the critical locations determined from that evaluation.
l 9012050156 9,01129 Q
PDC Ifg i
U.S'. Nuclear Regulatory Commission November 29, 1990 Additionally, Reference (c) indicated Byron Station would adopt a long-term inspection program to ensure the integrity of the RHR suction lines.
During the Spring 1990 refueling outage for Byron Unit 1, and the Fall 1990 refueling outage for Byron Unit 2, non-destructive examinations were performed on the four (4) welds which were Identifled by the evaluation as critical locations for each unit.
The welds examined were J7, J8 and J9 on line 1/2 RC04AB (suction line to RHR Pump 1/2 B from the Loop 3 Hot Leg) and weld J7 on line 1/2 RC04AA ($Uttion line to RHR Pump 1/2 A from the loop 1 Hot Leg).
The examinations of the welds and associated heat affected zones were performed utilizing enhanced ultrasonic techniques which ensure increased sensitivity for the detection of cracks.
The results of these examinations for Byron Units 1 and 2 revealed that no indications were found.
The inspections performed fulfill Bulletin Action 2 for Byron Station.
Additionally, the Inservice Inspection (ISI) Program at each station was revised to include the inspection of these lines (at the critical locations) at a frequency of every other refueling outage.
This letter completes the repcrting requirements and action items identified in Bulletin 88-08 Supplement 3 for Byron Station Units I and 2 Please direct any questions that you may have on this response to this office.
Respectfully, f
D.L. Taylor Generic Issues Administrator DT:Imw ZNLD608/30 cc: A.B. Davis - Regional Administrator, Region III A. Shia - Project Manager, NRR Resident Inspector - Byron OFFICI AL SE AL "
LYNN M.WLODARSKI Subsecribed and Sworn to NOT ARY PUMIC ST AIL Of ILLINDIS
" CC"* # 8 before me this c/ f day of We eh &%
, 1990 (b
s_)g te) D& M r Notary Public