ML17201Q415
| ML17201Q415 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, LaSalle, 05000000 |
| Issue date: | 04/11/1989 |
| From: | Silady J COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.084, RTR-REGGD-1.084 NUDOCS 8904210263 | |
| Download: ML17201Q415 (5) | |
Text
Common.Ith Edison 72 West Adams Street, Chicago, lllinoi.s Address Reply to: Post Office Box 767 Chicago, Illinois 60690 - 0767 Dr. Thomas E.. Murley, Director Off ice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 April 11, 1989
Subject:
Dresden Station Units 2 and 3 LaSalle County Station Units 1 and 2 Quad Cities Station Units 1 and 2 Alternate Damping Values for Piping Seismic Analysis NRC Docket Nos. 50-237/249, 50-373/374, and 50-254/265
Reference:
Letter from D.R. Muller to H.E. Bliss dated March 1, 1989.
Dear Dr. Murley:
The referenced letter requested Commonwealth Edison (CECo) to provide a schedule for re-evaluating the application of ASME Code Case N-411 damping values to previous seismic analysis of Class 1, 2, or 3 piping where such analyses are being used for long. term operation at the six CECo BWRs.
CECo has reviewed the 1985-1986 corresponde~ce referenced in your March 1, 1989, letter and the four conditions subsequently specified in Regulatory Guide 1.84 (Revision 24) for acceptable applications of Code Case N-411 damping and has concluded that no *re-evaluations,.. <:1.re needed.
The bases for this conclusion are discussed in Attachment A for Dresden and Quad Cities and in Attachment B for LaSalle.
8904210263 8 9 041 1 P-D*R*
ADOCK 0~000237 PDC p
T.E. Murley 2 -
April 11, 1989 Please contact this office should further information be required.
Very truly yours,
~LP-:A?.
J.A.~~---r~
Nuclear Licensing Administrator lm Attachments cc:
A.B. Davis - Regional Administrator, RIII 5606k S.G. DuPont - Senior Resident Inspector, Dresden T.M. Ross ~ Project Manager, NRR B.L. Siegel - Project Manager,~~RR P. C. Shemanski - Project Manger,* NRR R.D. Lanksbury - Senior Resident Inspettor, LaSarle-R.M. Higgins - Senior Resident In~pector, Quad Cities
--- ___ :__-:__-:::~--**----~...:. -~--=--
AT.rACHMENT A DRESDEN STATION UNITS.2 AND 3 QUAD CITIES STATION UNITS 1 AND 2 ALTERNATE DAMPING VALUES FOR PIPING SEISMIC ANALYSES Recirculation Ptimp Support System Applications As a result of an April 3, 1986, telephone conversation with NRR, CECo initiated design for Dresden 3 Recirculation pump support using N-411 damping and FSAR techniques.
Subsequently, a May 13 meeting with NRR indicated that the staff would no longer support their previous authorization on this application.
Accordingly, CECo decic;led to stop work on the N-411/FSAR modification and the supports were redesigned using FSAR spectra and methods.
The construction of the subject support was completed to full FSAR compliance as of October, 1986.
For Dresden Unit 2, Regulatory ~uide 1.61/FSAR loads were used for an interim operability justification.
During the subs.equent refueling outage (February, 1987) the subject supports were upg~aded to full FSAR compliance with work completed as of June 1987.
In conclusion, Dresden and Quad Cities Stations did not use PVRC damping (Code Case N-411) for long-term operations one the* subject system.
Therefore, no re-evaluation is required._
Other Applications CECo does not believe there are any applications of N-411 damping values on other systems at Dresden and Quad Cities Stations.
This will be further reviewed and confirmed by May 31, 1989.
5606k
ATI'ACHMENT B LASALLE COUNTY STATION UNITS 1 AND 2 ALTERNATIVE DAMPING VALUES FOR PIPING SEISMIC ANALYSES References (1):
Letter from E.G. Adensam (NRC) to D.L. Farrar (CECo)
-dated April 1, 1986;
Subject:
Authorization to Use ASME Code Case N-411 - LaSalle County Station, Units 1 and 2.
(2):
Letter from C.M. Allen (CECo) to H.R. Denton (NRC) dated April 18, 1986;
Subject:
LaSalle County Station Units 1 and 3, Snubber Reduction Topical Report, NRC Docket Nos. 50-373 and 50-374.
(3):
U.S. NRC Regulatory Guide 1.84, Revision 24, dated June 1986, "Design *and Fabrication Code Case Applicability ASME Section III, Division 1."
(4):
Letter from E.G. Adensam (NRC) to D.L. Farrar (CECo) dated July 18~ 1986;
Subject:
LaSalle County Station Units 1 and 2 Snubber Reduction Program.
(5):
Letter from J.J. Harrison (NRC, Region III) to Cordell Reed (CECo) dated August 31, 1988.
(6):
Sargent & Lundy Calculation SESD-185CC, Revision 00.
No re-evaluation of piping systems at LaSalle County Station is required because the requirements for the use of ASME Code Case N-411 as outlined in the (Reference 3) Regulatory Guide have been met.
The use of Code Case N~411 and conformance to the Regulatory Guide were documented in the 1987 update to the LaSalle County Station UFSAR.
A more detailed engineering justification for each of the four Regulatory Guide 1.84 conditions is provided below.
Item 1 - The response mode frequencies of the piping system are limited to 33 hz and below Applicability of this requirement i~ a strict sense is not possible at LaSalle because for piping systems affected by BWR hydrodynamic loads, significant piping system response can*occur at frequencies above 33 hz.
This item is dis6µssed briefly in References 2 and 4.
Specifically, Reference 4 requires that inclusion of additional modes will not result in more than a 10 percent increase in response.
Detailed procedures addressing high, frequency piping system response were reviewed by NRC Region III personnel an.c"! were accepted (see Reference 5).
This issue, therefore, requires no further action.
. ~- =-*------=-::...-
2 -
Item 2 - Current seismic spectra are use~.
CECo has verified that Sargen~ & Lundy Engineers used the current seismic spectra when generating the spectra utilizing ASME Code Case N-411 damping values; Documentation of the seismic spectra generation is con'tained* in Re~eren7e *6*. *
- Item 3 - Supports designed to dissipate -ene:gy ~re no.t used.
Reference 1 (which is R'e.ference ("l): ~f: the-,NRC request letter) represents NRC authorization for CECo to use the damping values specified in ASME Code N-411 on LaSalle County Station piping systems.
One of the restrictions identified in that letter specifically states.that energy absorbing supports are not to be used when analyzing a piping system using Code Case N-411 damping values.
Since all piping. analyses utilizing this Code Case were performed subsequent to the issue of Reference 1, no further action is required.
Item 4 - Piping with incipient stress corrosion cracking is not considered.
5606k An expanded statement regarding this issue as taken directly from Regulatory Guide 1.84 reads, "This Code Case is not.applicable to piping in which stress corrosion cracking has occurred unless a case-specific evaluation is made by the NRC Staff."
Nci stress corrosion cracking has occurred to date on LaSalle County Station piping systems.
The long-term effects have been addressed separately, however, through a CECo request to the NRC (Reference 2) to eliminate arbitrary intermediate break (AIB) postulation on LaSalle County Station piping systems.
The NRC agreed (Reference 4) that sufficient technical bases exist to justify eliminating the requirements for mechanical pipe rupture protection against AIB's.
Therefore, no further action is required on this item.