TXX-6057, Forwards Response to 860911 Request for Addl Info Re Elimination of Arbitrary Intermediate Pipe Breaks. Configurations of Eliminated Piping Attachments within Five Diameters of Breaks Will Be Identified
| ML20215J383 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/21/1986 |
| From: | Counsil W, Keeley G TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Noonan V NRC - COMANCHE PEAK PROJECT (TECHNICAL REVIEW TEAM) |
| References | |
| TXX-6057, NUDOCS 8610240416 | |
| Download: ML20215J383 (3) | |
Text
~
Log # TXX-6057 File # 10010 903.6 TEXAS UTILITIES GENERATING COMPANY BEYWAY TOWER. 4ee MostT,5 OI.JVE STREBLT.1.B. 88. DALLAlt, TEXA8 76398 October 21, 1986
.T.M".Eff.U*L Director of Nuclear Reactor Regulation Attention: Mr. V. S. Noonan, Director Comanche Peak Project Divis' ion of Licensing U. S. Nuclear Regulatory Commission I
Washington, D.C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET N05. 50-445 AND 50-446 ARBITRARY INTERMEDIATE PIPE BREAKS REFERENCE 1: TXX-4872 W. G. Counsil to V. S. Noonan, July 29, 1986.
Dear Mr. Noonan:
Attached is the response to your request for additional information dated September 11, 1986, concerning elimination of arbitrary intermediate pipe breaks.
Very truly yours, l
W. G. Counsil By:
~
G. S. Keeley Manager, Nuclear icensing BSD/amb Attachment c - NRC (0 + 40 copies)
A. L. Cook 8610240416 861021 PDR ADOCK 05000445 A
PDR I
ih
.4 vt11%90% OF 17% AS LTilITIEN Ft.FCTRIC tinit*A%Y
TXX-6057 October 21, 1986 Attachment Page 1 Q210.9 Your response to Q210.1 in your letter dated July 29, 1986 concerning the elimination of arbitrary-intermediate pipe breaks requires additional information. The need exists to demonstrate an equivalent level of safety to that provided in the Standard Review Plan in the evaluation of potential pipe breaks in the vicinity of welded attachments to piping.
It is requested that more detailed information be provided concerning the use of welded attachments in the vicinity of those arbitrary intermediate breaks to be eliminated.
Specifically, the staff requests that you provide the following information:
a.
Identify all welded piping attachments within five pipe diameters of the arbitrary intermediate break to be eliminated.
b.
For each welded attachment, identified in (a) above, provide the system, stress package number, piping isometric drawing number, pipe support number, building location, and pipe stress levels at the welded attachment.
c.
Provide a sketch of the piping configuration in the area near the welded attachment and arbitrary intermediate break location.
d.
Describe the type of welded attachment involved (e.g. lug, stanchion, trunnion) and provide a sketch of the welded attachment and support arrangement.
e.
For those systems susceptible to large, unanticipated dynamic loads.
(e.g. main steam and feedwater), provide an assessment of the weak link in the piping to pipe support load path.
R210.9 a.
The identities and configurations of all welded piping attachments within five diameters of each of the Arbitrary Intermediate Breaks (AIB's) to be eliminated will be identified and submitted for review by NRC.
Since the postulated break locations for CPSES Units 1 and 2 will be based on the pipe stress analysis results of the SWEC requalification process (Reference 1, Q210.7), the AIB's to be eliminated and the adjacent welded piping attachments, where applicable, will be finalized and submitted in 4
early 1987 for Unit 1 and in mid 1987 for Unit 2.
b.
The piping system, stress package number, piping isometric drawing number, pipe support number, building location, and pipe stress levels at the welded attachments identified in (a) will be included in the submittals.
c.
A sketch of the piping configuration in the areas near the welded attachment and AIB will be included in the submittals.
TXX-6057 Octcber 21, 1986 Attachment Page 2 d.
The type of welded attachments and the support arrangement will be included in the submittals.
e.
For piping systems that are susceptible to large unanticipated dynamic loads, such as water hammer in main steam and feedwater piping, an assessment of the weak link in the piping to pipe support load path will be included in the submittals for all welded attachments within five nominal pipe diameters of the AIB's to be eliminated in those systems.
Q210.10 Your response to Q210.2 in your letter dated July 29, 1986 concerning arbitrary intermediate pipe breaks is not acceptable.
The stress reduction factor provided in the ASME Code Section III for thermal stress cycles greater than 7000 cycles applies to general bending stresses only. The staff concern is related to the potential for localized bending and thermal gradient stresses which may occur in the main steam and feedwater systems at locations of welded attachments.
Provide a worst-case assessment of the potential fatigue effects at the welded piping attachments in the main steam and feedwater systems due to local bending and thermal gradient stresses.
R210.10 As was stated in our response to NRC Question Q210.2 (Reference 1), the local bending stress due to integral welded attachments is added to the primary membrane and general bending stresses to get the total stress used to determine the arbitrary intermediate break locations.
In addition, in the main steam and feedwater systems, if welded attachments exist within five nominal pipe diameters of the AIB to be eliminated, a worst case assessment of the potential fatigue affects at the. welded attachments due to local bending and thermal gradient stresses will be performed and included in the submittals for the response to Q210.9.
_ - _ _ _