ML18116A280
| ML18116A280 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/13/1979 |
| From: | Neighbors J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7908070758 | |
| Download: ML18116A280 (8) | |
Text
{{#Wiki_filter:-
~
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 50-280 JUL 1 3 1979 LICENSEE: FACILITY: SUBEJCT: Virginia Electric and Power Company (VEPCO) Surry Unit No. 1
SUMMARY
OF MEETING HELD ON JUNE 21 AND 22, 1979 TO REVIEW PIPE STRESS ANALYSES The subject meeting was held with VEPCO and Stone and Webster (S&W) to review the modifications required to pipe supports resulting from pipe stress reanalyses or "as-built" verification. A list of attendees is attached (Attachment 1). The following table lists the supports which we reviewed in detail and gives the reason for the modification. provides details of the modifica-tions for each problem. Problem No. System Reason 508 RHR Seismic 540 RHR Seismic 548A C&RS As-Built 555* LHSI 562 C&RS 630 PSR As-Built As-Built Thermal Verificati~~~hl!f/} Verification 'l..li1Jqj19,Pt /ti),, Verification 'I I Yl/)!}ft1r.. 'l!ij/ii lO!!J ~ 731A* LHSI As-Built 731B* LHSI As-Bui'l t 743 LHSI As-Built Ver~ f~ cat~ on
- II IJ/J.,,!( tD;iJ!lr.~.Y Ver1f1cat1on lhl!JP,y Verification 1
- Supports overstressed At this time, 42 analyses are being analyzed by S&W, of which 35 are complete, 4 are under QA review and 3 are yet to be submitted to QA.
Eleven problems require modification, nine of which are discuss.ed above ~L and two for which details are not available. ~~ Twenty-seven analyses ( NS C) in Ca 1 ifo rn i a. 21 completed analyses are being performed by Nuclear Services Corporation (Ji;_-{;) Twenty-one analyses are complete. Nine of the require modifications to correct overstress
Meeting Summary for Surry 1 and/or support overstress. These modifications were not analyzed at this time. Attachments: As Stated cc: w/attachments See next page g '; ~ct Manager Operating Reactors Branch #1, DOR
Meeting Summary for Surry Unit No. 1 Docket File NRG PDR Local PDR NRR Reading ORBl Reading H. Denton E. Case D. Eisenhut G. Zech W. Gammi 11 J. Mi 11 er L. Shao R. Vollmer W. Russe 11 B. Grimes T. J. Carter T. Ippolito R. Reid A. Schwencer D. Ziemann V. Noonan P. Check G. Lainas G. Knighton e Chief, Systematic Evaluation Branch Project Manager DOR Licensing Assistant
- oELD OI&E (3)
R. Fraley, ACRS (16) ~rogram Support Branch TERA J. R. Buchanan NRC Participants Mr. Michael W. Maupin Hunton and Williams Post Office Box 1535 Richmond, Virginia 23213 Swem Library College of William and Mary Williamsburg, Virginia 23185 Donald J. Burke U.S. Nuclear Regulatory Commission Region I I. Office of Inspection ~nd Enforcement* 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 July 13, 1979
NRC ~Neighbors A. Lee W. Russel 1 VEPCO W. Spencer C. M. Robinson S&W W:-Chamberl a in P. Wi 1 d D. King B. Crowe D. Esielionis R. Hankinson P. Papi E. Homer ATTACHMENT 1 LIST OF ATTENDEES
1-ATTACHMENT 2 DESCRIPTION OF MODIFICATIONS Problem 508, Residual Heat Removal System To reduce pipe stresses at the elbows on the ~ischarge side of the RHR pumps lA and lB modifications are required. The overstressed condition occurs in the low pressure portion of the piping system. Four supports are required - two on the pump's discharges and two on the suction. Some snubbers were found to be overloaded on the suction line. (The supports for the suction MOVs required two additional snubbers between MOVs.) One snubber was required between the MOV and common suction line. See also VEPCO letters dated June 12 and 18, 1979. Problem 540, Residual Heat Removal System Additional support was found between A-15 and C-19 anchors. Also C-19 was a 3-way vice a two-way direction support. Rod hangers were removed since C-19 was 3-way to reduce thermal stress. The two inch relief line had not been modeled between A-15 and C-19. The main line was four inches. Inertial stress required addition of anchor six feet from two inch relief valve to account for seismic loading which previously had not been considered (interaction of two inch to four inch line)..
- Problem 548A, Containment and Recirculation Spray The modification is required because of the as-built condition.
The difference was a lateral displacement of six feet in a 13-1/2 foot run of ten inch pipe. In addition, a ten inch check valve and a 10 x 8 inch reducer are located in the lateral displacement. Pipe was previously modeled as a smooth bend with the reducer and valve nearer anchor point. A horizo~tal snubber was added to reduce pipe displacement and inertial stress near inside wall of contain-ment (anchor) which was near 11 new 11 bends (as-built bends). Deviations are significant and would require reanalysis in accordance with S&W procedures. All changes of more than six inches in support location, pipe length, etc. require ~eanalysis. Problem 555, Low Head Safety Injection System This modification is required because of the as-built condition. As-built verification erroneously classified three supports as 11 vertical/ lateral" which were 11verticaP only. These were subsequently determined to be vertical only and the analysis was satisfactory. Use of single lateral shock suppressor was selected to prevent thermal load problems. Pipe stress was satisfactory. Movement on the anchor was significant
e due to fifteen foot moment arm (12" pipe) and no lateral support. Original SHOCK 2 moment was 70,000 ft-lb: after addition of shock suppressor was 7,000 ft-lbs. [70,000 ft-lb. moment is unacceptable today J. Problem 562, Containment and Recirculation Spray System Anchor on spray ring header - The original design was located at riser Tee. The actual design was located 6 16 11 to one sideof the Tee. The result was that the segment of ring header must be incl~ded in model. Also, the riser pipe original design consisted of a short run of pipe with one bend. Actual field run has three segments with one segment being 15 18 11 long. The original design had two pieces of pipe with one bend whereas the iactual has four pieces with three bends. The original analyses (SHOCK 2) was based upon typical ring. Because of as-built differences, all were reanalyzed. Modifications consist of changing a rod hanger to a spring hanger because of thermal loading and adding a vertical constraint in place of a spring hanger (would have seismic overstress without constraint}. Problem 630, Pressurizer.Spray and Relief System Vertical pipe from PORV to Flash Tank is supported from building structure. Code safety relief line discharge (supported on pressurizer head) forms lateral (45°) intersection with next pipe run. Two inch thermal growth in pressurizer results in thermal stress at upper lateral section 45° intersection. By removing anchor below lower lateral, more flexibility was obtained resulting in less stress. Overstress was caused by applying stress intensification factor as currently required. This piping, according to mill certification is better* than the code minimum. Problems 731A and B, low Head Safety Injection System The modifications to these systems result from as-built verification. Axial movement of support plus flexibility of support resulted in about 12 inches axial support movement. The modification involves adding a diagonal brace and is necessary to get within limits of pipe stress analysis assumptions.
- Problem 743, Low Head Safety Injection System This modification results from as-built verification.
In the original analyses the support was four feet from elbow. The actual location is 17'8" from elbow. Existing support was shimmed three inches on each side plus stiffened to transfer load in lateral direction. There was about three to four inches of displacement of pipe prior to stiffening.
e '\\~t{ M?tfog Summary for Surry 1 2 - JUL 1 3 1979_ I
- /'... },. and/or support overstress. _ These\\\\
1 rnodi fi cations were not analyzed at
- z'.it~this time.
1 <~\\,, Attachments: As Stated
- cc: w/attachments See next page cP I
')_. 1.!1 f' ( '/, J. D. Neighbor$~ Project Manager Operating Reactors Branch #1 ~ DOR \\ \\ ~.~~~*********.P.~.~.:.~.Ai~-~-.......................... *************************.. :........................................... 6"n,;-Jn* 0-"*~*;J 1mt~,~~)........ ***************............................. ********....................................... : ffllC roRM 318 (9-76) NRCM 0240 U,Q, GOVl!RNM!INT.. RINTING OP'FICl'I: 1071 '"-ZGB
- 70G*}}