ML20207C584
| ML20207C584 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 12/24/1986 |
| From: | Kowalski S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Butler W Office of Nuclear Reactor Regulation |
| References | |
| CON-#187-2115 OL, NUDOCS 8612300181 | |
| Download: ML20207C584 (19) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 DEC 241986
- s. J. KOWALSKI ViCE PRESIDENT s...
Dr. Walter Butler. Director BWR Froject Directorate 4 Division of BWR Licensing U.S. Nuclear Regulatory Commission Weshington, DC 20555
Subject:
Use of ASME Code Case N-411 for Limerick Unit 2
References:
(1) Letter, W. R. Butler (USNRC) to E. G. Bauer (PECo),
dated May 30, 1986 - Same Subject (2)
Summary of Meeting between NRC Staff and PECo on October 8, 1986 - Same Subject Prepared by R. E. Martin (USNRC), dated October 16, 1986 (3) Summary of Meeting between NRC Staff and PECo on November 7, 1986 - Same Subject Prepared by R. E. Martin (USNRC), dated November 21, 1986 (4) Meeting between NRC Staff and PECo on December 3, 1986 -
Same Subject
Dear Dr. Butler:
to this letter confirms and documents the information presented in the reference 4 meeting that provides the basis for the determination of the similarity of the following piping systems / lines (lines) inside containment:
I. Main Steam Lines A*,
B*, C* and D II. Recirculation Loops A and B*
III. Feedwater Lines A and B*
IV. RHR Return Lines A & B*
This information shows that the designs of the lines which have not been specifically analyzed by the time histcry methodology (identified above by an asteriti) are acceptable because of the demonstrated similarities of those lines with the lines that were analyzed by time history methods (ref. 3).
As discussed in the reference 4 meeting, Philadelphia Electric is pursuing the study of the balance of the lines that were analyzed utilizing the independent support motion (ISM) method of dynamic analysis with code case N-411 variable damping. These studies are using the ISM (absolute sum) method of analysis with R.G. 1.61 damping values and/or enveloped response spectra methods with code case N-411 0
variable damping.
~
8612300181 861224 PDR ADOCK 05000353 A
..m._
l Please contact us if you have any questions concerning the-information presented in this letter and the attachment, r
}
Sincerely.
-1 i
i i
KAH/pd12188606 Attachment i
u Copy to: See Attached Service List l
1 1
4 -
i i
1 1
1 I
i I
Copy to: Troy B. Conner, Jr. Esq.
(w/ enclosure)
Ann P. Hodgdon, Esw.
(w/ enclosure)
Mr. Frank R. Ronano (w/ enclosure)
Mr. Robert L. Anthony (w/ enclosure)
Ms. Phyllis Zitzer (w/ enclosure)
Charles W. Elliot, Esq.
(w/ enclosure)
Barry M. Hartman, Esq.
(w/ enclosure)
Mr. Thones Gerusky (w/ enclosure)
Director, Penna Energency (w/ enclosure)
Managenent Agency Angus R. Love, Esq.
(w/ enclosure)
David Wersan, Esq.
(w/ enclosure)
Robert J. Sugarnan, Esq.
(w/ enclosure)
Kathryn S. Lewis, Esq.
(w/ enclosure)
Spence W. Perry, Esq.
(w/ enclosure) day M. Gutierrez, Esq.
(w/ enclosure)
Atomic Safety & Licensing (w/ enclosure)
Appeal Board Atomic Safety & Licensing (w/ enclosure)
Board Panel Docket & Service Section (w/ enclosure)
Mr. E. M. Kelly (w/ enclosure)
Mr. Timothy R. S. Champbell (w/ enclosure)
KAH/pd12248602 L
2 ATTACHMENT 1 1.
Main Steam Line Similarity The time history analysis of main steam line D is appilcable to main steam lines A, B and C because of similarities in natural frequencies of the lines, governing load combinations, response spectra grouping and stress levels and restraint loads under the governing upset load conditions as discussed below:
A.
Frequencies The main steam ploing natural frequencies within modes are similar.
Frequency (HZ)
MDDE NO.
MS A MS B MS C MS D 1
6.5 5.4 5.2 6.5 2
11.2 11.7 9.7 11.5 3
14.4 13.1 12.2 14.5 B.
Governing Load Continations The governing load conbination for all four main steam lines is the operating basis earthquake plus safety relief valve 1ift (Upset Load Canbinatlon).
C.
Response Spectra Grouping The main steam line input response spectra groups are identical.
Main Steam Line Response Spectra Grouping MS A MS B MS C MS D l
Group 1 RPV Nozzle RPV Nozzle RPV Nozzle RPV Nozzle l
l Group 2 Snubbers Snubbers Snubbers Snubbers SA1, SA2, SB3, SB4 SC4, SC3 SD1, SD2, SA6 SB5, SB7 SC5 SD6 Group 3 Penetration Penetration Penetration Penetration D.
Stress Levels and Restraint Loads Main steam line D was analy7ed by the time history methodology using FSAR OBE damping. The results of that analysis were presented to the NRC in a meeting on November 7,1986 ccrnparing stress and restraint load predictions of ISM / Code Case N-411 with time history predictions. The maximtm stress prediction occurred at the same group of components and all stresses were within design basis allowables. The stress and restraint load predictions under the upset load ccmbination from the ISM /N-411 analysis'of the four main steam lines are tabulated below to show that the predictions are similar.
Pipe Stresses Location MS A MS B MS C MS D Vessel Nozzle 10,400 psi 9,878 psi 9,500 psi 9,352 psi First Downstrean 7,181 psi 6,282 psi 5,500 psi 5,112 psi Elbow Upper SRV Inlet 17,941 psi 15,690 psi 16,527 psi 17,512 psi Branch Lower Rollef Valve 11,132 psi 14,087 psi 12,159 psi 13,163 psi Inlet Branch Main Stean 7,945 psi 8,468 psi 8,278 psi 8,117 psi Isolation Valve Inlet Penetration Nozzle 8,892 psi 10,477 psi 10,253 psi 9,530 psi Restraint Loads Sr.ubber #/ load Snubber #/ load Snubber #/ load Snubber #/ load SA1 SB3 SC3 SD1 27.3 kips 30.5 kips 28.3 kips 26.7 kips SA2 SB4 SC4 SD2 21.5 kips 19.0 kips 22.5 kips 20.4 kips SA6 SBS SCS SD6 20.1 kips 19.0 kips 22.5 kips 18.8 kips SB7 17.4 kips Main stean line B has an additional snubber (SB7) compared to its mirror Image line C.
Nevertheless, load predictions are similar for the two lines. The extra snubber provides additional restraint that adds to design conservatism. The safety relief valve discharge lines have a negligible effect on the main stean line because of the large difference in relative stiffness between the 26 inch main steam line and the 12 inch and snaller branches.
II.
Recirculation Loop Similarity The tine histcry analysis of recirculation loop A is applicable to recirculation loop B because of similarities in natural frequencies of the loops, governing load combinations, response spectra grouping and stress levels and restraint loads under the governing faulted load combinations as discussed below:
A.
Frequencies The recirculation piping natural frequencies within nodes are similar.
Frequency (HZ)
Mode No.
Recirc. Lecp A Recirc. Loop B 1
7.4 7.5 2
7.6 7.7 3
10.2 10.0 B.
Governing Load Conbination The governing load combination for both recirculation loops is annulus pressurization plus safe shutdown earthquake (Faulted Load Contination).
C.
Response Spectra Grouping The grouping of the response spectra are identical for both loops.
Recirculation Loop Response Spectra Grouping Loop A Loop B Group 1 RPV Nozzles RPV Nozzles Group 2 Snubbers SA2, SA3, SA19, Snubbers SB2, SB3, SA17, SA23 SB19, SB17, SB23 Group 3 Snubbers SA4, SAS Snubbers SB4, SBS Group 4 Snubbers SA6, SA7 Snubbers SB6, SB7 D.
Stress Levels and Restraint Loads Recirculation loop A was analyzed by the tine history nethodology using FSAR danping for the safe shutdown earthquake and annulus pressurization loads. The results of that analysis were presented to the NRC in a neeting on Novenber 7,1986 comparing stress and restraint load predictions of ISM / Code Case N-411 with time history predictions. Both tine history and N-411 nethods gave similar predictions at similar canponents.
The ISM / Code Case N-411 stresses and restraint load predications under the faulted load conbination are tabulated below to show the similarity of the predictions for loops A and B.
Pipe Stresses Location Loop A
_ Loop B RPV' Suction Nozzle 12,466 psi 12,853 psi ~
RHR Suction Tee No Branch 24,895 psi Suction Riser Hanger Lug 20,479 psi 19,499 psi Elbow at ;Punp Suction 41ozzle 9,170 psi 9,424 psi Recirc. Pump Discharge Nozzle.
11,434 psi' 11,691 psi RHR Tee Discharge 27,303 psi '
24,409 psi Header Sweepolet Connection 21,137 psi 21,295 psi Reducer at Center Riser Cross 20,314 psi 20,543 pst Restraint Loads Loop A Loop B Snubber S2 83.8 klps 85.1 kips Snubber S3 81.6 kips 85.1 kips Snubber 54 68.0 kips 70.3 kips snubber SS 60.8 kips 66.2. kips Snubber S6 48.9 kips 45.4 kips Snubber S7 47.4 kips 47.4 kips Snubber S17 28.1 kips 31.4 kips Snubber S19 30.0 kips 38.4 kips Snubber S20 35.0 kips 36.2 kips Snubber S23 27.4 kips 29.5 kips The only configuration difference between loop A and B Is the presence of the RHR shutdown cooling suction line fran the loop B suction riser. The stresses on the nearby RPV suction nozzles and in the suction piping are nearly identical on Loops A and B.
III. Feedwater Line Similarity The tire history analysis of feedwater line A is applicable to feedwater-line B because of similarities in layout and support 1
locations, natural frequencies of the lines, response spectra H
groupings 'and. stress levels and restraint loads under the governing upset load conditions as discussed below:
A.
Layout and Support Locations The piping layout and support locations for the feedwater line B are mirror Image to feedwater line A with exception of the RWCU line (a 4 inch branch line) and differences in specific support locations and/or orientations. This small 4" diameter RWCU line has an insignificant influence on the 24" diameter feedwater line. Therefore, a direct comparison can be made between the feedwater lines.
B.
Frequencies The feedwater piping natural frequencies within nodes are similar.
Modal Frequencies Mode No.
Feedwater Line A Feedwater Line B 1
7.21 6.73 2
8.97 8.23 3
9.70 10.07 4
10.66 10.93 5
13.80 11.47 6
14.39 12.97 7
16.85 14.25 8
18.73 18.11 9
21.21 21.09 10 22.87 22.12 C.
Response Spectra Grouping The feedwater input response spectra groups are identical.
Feedwater Response Spectra Grouping Feedwater line A Feedwater Line B Group 1 RPV Nozzle RPV Nozzle Group 2 All Supports on the All Supports on the Main Feedwater Line Main Feedwater Line D.
Governing Load Canbination The governing load combination for both feedwater lines is operating basis earthquake plus safety relief valve lift.
(Upset Load Combination).
E.
Stress Levels and Restraint Loads Feedwater line A was analyzed by the time history nethodology using FSAR damping. The results of that analysis were presented to the NRC in a neeting on November 7, 1986 conparing stress and restraint load predictions of Code Case N-411 with time history predictions. The stress and restraint load predictinns under the upset load combination from the ISM /N-411 analysis of the feedwater lines are tabulated below to show that the predictions are similar.
l Pipe Stresses Node Point Feedwater Line A Feedwater Line B L
5 12,332 psi 11,425 psi I
10 7,398 psi 7,237 pol 20 9,312 psi 8,838 psi l
50 5,383 psi 5,280.si 81 8,772 psi 8,341 psi 121 10,090 psi 12,191 psi L
144 9,110 psi 11,404 psi 162 10,565 psi 15,424 psi 164 10,596 psi 13,239 psi 170 8,739 ps!
11,246 psi 180 13,579 ps!
16,055 psi 104 9,612 psi 9,142 psi 110 8,425 psi 8,397 psi-115 13,884 psl 13,878 psi 64 8,681 psi 9,'287 psi 70 8,480 psi 8,676 psi 75 13,822 psi 13,590 psi Restraint Loads Node Point Feedwater Line A Feedwater Line B l-43 15.3 kips 13.6 kips l
83 12.5 kips 12.8 kips 130 4.8 kips 5.1 kips L
137 7.7 kips 7.2 kips 164 7.0 kips 14.0 klps 106 10.9 kips 10.3 kips i
61 13.4 kips 7.5 kips 66 12.9 kips 6.9 kips l
The table above demonstrates that the stresses and restraint loads are similar. There are localized areas where minor differences In restraint orientations have affected the local distribution of forces l
and noments.
In all cases the restraint load is within the allowable i
design load.
IV.
RHR Shutdown Cooling Return Systan Similarity i
The time history analysis of RHR shutdown cooling return line A is i
applicable to RHR return line B because of similarities in layout and support locations, natural frequencies of the lines, response spectra groupings and stress levels and restraint loadings under the governing faulted load combination:
1 A.
Layout and Support Locations The piping layout and support locations for the RHR return line B are mirror Image to RHR return line A.
B.
The RHR return line piping frequencies within modes are similar.
f
- 7~-
Modal Frequencies Modei RHR Return Line A RHR Return Line B 1
3.9 3.8 2
4.6 4.5 3
7.9 8.3-4 11.3 11.8 5
12.6 12.5 6
15.9 15.0 7
16.1 16.3 8
20.7 21.0 9
21.9 22.7 10 25.0 24.0 C.
Response Spectra Grouping The RHR return line response spectra groups are similar.
Both of the RHR return lines are analyzed in a coupled analysis with their respective recirculation piping loops.
RHR Return Line Response Spectra Grouping Line A Line B (Node Points in Group)
(Node Point in Group)
Group 1 Snubber at 292,295 Snubbers at 266,268,282 Group 2 Snubbers at 275 & 318 Snubbers at 254 Penetration at 205 Penetration at 205 D.
Governing Load Combinations The governing load combination for the significant components on both RHR return lines is annulus pressurization plus safe shutdown earthquake (Faulted Load Combination).
E.
Stress Levels and Restraint Loads RHR return line A was analyzed by the time history methodology using FSAR danping. The results of the analysis were presented to the NRC in a meeting on Noveaber 7, 1986 comparing stress and restraint load predictions of ISM / Code Case N-411 with tine history predictions. The stress and restraint load predictions under the faulted load combination fran the ISM /N-411 analysis of the two RHR return lines are tabulated below to show that the predictions are similar.
Pipe Stresses Line A Line B Node Point Node Point 205 28,434 ps!
205 24,581 psi 208 12,662 psi 208 11,851 psi 210 13,305 psi 210 12,009 ps!
290 15,217 psi 262 13,103 psi 314 11,838 psi 274 10,708 psi 320 18,540 psi 285 16,674 psi 350 15,920 ps!
297 16,697 psi Restraint Loads Line A Line B Node Node 275 20.6 kips 254 18.8 kips 292 31.6 kips 266 18.2 kips 295 14.9 kips 268 13.6 kips 318 34.5 kips 282 23.4 kips The differences between line A and line B result from minor differences in restraint orientations and the differences in response spectra grouping between the snubber at node 318 and the snubber at node 282.
In all cases the restraint load is within the allowable design load.
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