ML20046B858
| ML20046B858 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/30/1993 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 93-434, NUDOCS 9308060322 | |
| Download: ML20046B858 (4) | |
Text
~ ~t.
s,.
VIHOINIA }$LECTHIC AND.}'OWER COMI*ANY Ricnnown, VIRGINIA 23261 July 30, 1993 United States Nuclear Regulatory Commission Serial No.93-434 Attention: Document Control Desk NL&P/EJW Washington, D.C. 20555 Docket Nos.
50-339 License Nos. NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNIT 2 liiSERVICE INSPECTION PROGRAM SECOND TEN YEAR INTERVAL
.l RELIEF REQUEST SPT-14 REVISION By letter dated February 16,1993, Relief Request SPT-14 was initially submitted to
)
address the ASME Section XI requ:rement to remove bolting, when leakage is observed at the bolted connection durinp a visual (VT-2) examination. That submittal is hereby revised and replaced with the enclosed Relief Request SPT-14.
j I
The initial relief request did not differentiate between class coded systems that contain boric acid and systems that do not contain boric acio. Relief Request SPT-14 is being.
i revised to limit botting removal to situations where boric acid wastage could be a factor. As with the previous version of this relief request, SPT-14 is needed for North
.)
Anna Unit 2 prior to the next refueling outage, which is currently scheduled to begin on September 4,1993.
This ~ request has been approved by the North Anna Station Nuclear Safety.and -
Operating Committee.
If'you have any questions concerning these requests, please contact us.
Very truly yours,
/,'
(
cT
- M i
(,1 (Cm/
W. L. Stewart Senior Vice President - Nuclear Enclosure 0500M 0/
t 9308060322 930730 M
PDR ADOCK 0500o339 bi G
PDR has.
'(
l cc:
United States Nuclear Regulatory Commission Region ll 101 Marietta Street, N.W.
Suite 2900 Atlanta, GA 30323 i
NRC Senior Resident inspector North Anna Power Station t
.1 r
+
5 a
i
1 i
7 NORTH ANNA UNIT 2 RELIEF REQUEST SPT-14 1.
Identification of Components Class 1,2, and 3 pressure retaining bolting (North Anna Unit 2).
ll. Impractical Code Requirements IWA-5250 (a) (2) states, "if leakage occurs at a bolted connection, the bolting shall be removed, VT-3 visually examined for corrosion, and evaluated in accordance with IWA-3100...."
lil. Basis For Relief Typically pressure testing required by the Code will identify mechanical connection leakage from gasket or packing sources. This leakage is evaluated routinely during or following the test, and additional torquing or other corrective measures on the bolting is applied to eliminate the leakage.
Generally, this type leakage is not active long enough to cause component damage. Also, some materials are not affected by boric acid wastage. Inl some instances testing occurs while containment is subatmospheric and just prior to reactor criticality. Requiring that bolting be removed in these instances for rr.n,or leakage would severely interrupt the normal start up schedule.
Additionally, the Code requirement does not incorporate previous NRC commitments associated with boric acid wastage on bolting.-
North Anna will examine safety-related components for boric acid leakage at the start of a reactor refueling. Each component affected by boric acid leakage will be evaluated for potential damage, and corrective action will be taken as appropriate. In accordance with commitments made previously to NRC Generic Letter 88-05 and in relief request SPT-12, a supplemental examination of Class 1 Category B-G-1 and B-G-2 bolting is also conducted every refueling outage. This supplemental examination is in excess of the normal inservice inspection program requirements. The current Code requirement assumes no additional examination or evaluation has taken place, and the Code makes the conservative assumption that leakage found has occurred for a sufficient time period to cause damage. This approach is impractical, when compared to the alternative arrangements proposed.
l Page 1 of 2 a
e
e RELIEF REQUEST SPT-14 Continued:
IV. Proposed Alternate Requirements For bolting examined during pressure tests (Class 1 system leakage, Class 1 hydrostatic, and Class 2 pressure tests scheduled in association with the Class 1 tests) which are conducted just prior to start up in subatmospheric conditions and in which leakage is identified near the bolted connections, bolting will be evaluated for removal need. The removal need will be based upon the extent of the leakage, correction requirements, and results of previous examinations conducted during that refueling outage.
This evaluation shall be subject to the review of the Authorized Nuclear Inservice Inspector (ANil). Botting in any situation requiring removal and visual (VT-
- 3) examination may be limited to one bolt nearest the leakage source. If that bolt has evidence of degradation, then all other bolting in the connection shall be removed, visually (VT-3) examined, and evaluated to the Code requirements. The limitation of selecting only one bolt initially is the same as the Code requirements found in the 1992 Edition of ASME Section XI, IWA-5250 (a) (2). Additionally, bolting removal, would be limited to bolting material affected by boric acid wastage, such that a visual (VT-3) examination would identify this condition.
Page 2 of 2 l
-. -