ML20112C183
| ML20112C183 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 03/19/1985 |
| From: | Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| CON-#285-203 OL, NUDOCS 8503210345 | |
| Download: ML20112C183 (11) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 23O1 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 JOHN S. KEMPER V IC E-PR E SID E N T speeswss neses Asso sesss ARCee tiarch 19, 198S Mr. A. Schwencer, Chief Licensing Branch No. 2 Division of Licensing U. S. Nuclear Regulatory Conmission Washington, DC 20555
Subject:
Limerick Generating Station High Energy Line Break Analysis
Reference:
Letter from A. Schwencer, NRC, to E. G. Bauer, Jr.,
PECo, dated February 26, 1985 Flies:
GOVT 1-1 (NRC)
QUAL 12 (Design Review)
Dear Mr. Schwencer:
The reference letter requested additional Information regarding the analysis of Jet impact loads resulting frcm postulated high energy 11ne breaks. The requested information, as well as responses to the concerns raised by NRC staff during a meeting on March 5, 1985, are contained in the attached report.
This report which basically confirms the responses given in the March 5,1985 meeting, reflects the results of our completed efforts and confirms the adequacy of the current plant design. The results of this work are currently being incorporated into the appropriate project doctmentation.
We beIIeve that this response is sufficient to allow closure of this item. However, should you have any questions please do not hesitate to contact us.
Sincerely,
$ $ Kf P
GdB/pdO3128507 pog See Attached Service List I)
C0tHONWEALTH OF PEtNSYLVANIA ss.
' COUNTY OF PHIUOELPHIA
- d. S. Kermer being first duly sworn, deposes and says:
That he is Vice President, Engineering and Research of Philadelphia Electric Company, the Appilcant herein; that he has reviewed the foregoing information regarding high energy line break analysis for Limerick Generating Station and kncwns the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, Information and belief.
Q/ T AC f.
[ Vice Presideht Subscribed and sworn to before me this [k ay of March 1985 lac 6Akt Notary Pubi'Tc PATRtCIA D. SCHOtf Natiwy Pu%c, PN.cebsia, erAuftsin co.
Ny ComranAm Loues fritary 10, 1985 GJB/pdO3128508 L
cc: Judge Helen F. Hoyt (w/ enclosure) dudge Jerry Harbour
.(w/ enclosure)
Judge Richard F. Cole (w/ enclosure)
Troy B. Conner, Jr., Esq.
(w/ enclosure)
Ann P. Hodgdon, Esq.
(w/ enclosure)
Mr. Frank R. Romano (w/ enclosure)
Mr. Robert L. Anthony (w/ enclosure)
Ms. Phyllis Zitzer (w/ enclosure)
Cliaries W. Elliot, Esq.
'(w/ enclosure)
Zori G. Ferkin, Esq.
(w/ enclosure)
Mr. Thomas Gerusky (w/ enclosure)
-Director, Penna. Emergency (w/ enclosure)
Management Agency Angus R. Love, Esq.
(w/ enclosure)
David Wersan, Esq.
(w/ enclosure)
Robert d. Sugarman, Esq.
(w/ enclosure)
-Martha W. Bush, Esq.
(w/ enclosure)
Spence W. Perry, Esq.
(w/ enclosure)
Jay 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. James Wiggins (w/ enclosure)
Mr. Timothy R. S. Campbell (w/ enclosure)
March 15, 1985
.i.a.
4 JET IMPINGEMENT ANALYSIS OF LARGE PIPE
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SUMMARY
The Limerick project pipe rupture analysis program required that jet impingement loads resulting f rom high energy line breaks be considered on all piping with diameter less than the ruptured pipe.
An exclusion was made for jet imping e-m'ent loads on piping equal to or greater than the ruptured pipe diameter and wall thickness on the basis that this grouping was excluded from pipe whip consideration for equal or heavier wall thicknesses and that jet impingement loads can be shown to be less than pipe whip loads.
The Limerick project position is discussed in IDVP potential finding PPR 019.
Because of the differences in the nature of the loads from a whipping pipe and jet flow, the NRC does not concur with this position.
The NRC requested Limerick to ' assess the effects of jet impingement loads on piping and supports
, required for safe shutdown where the, piping diameter is equal to or greater than the diameter of the ruptured pipe (Ref. 1).
4 In response to this request we have reviewed all break locations and identified all potential jet impingement target piping with a diameter equal to or greater than the ruptured pipe that could see jet impingement loads.
Jet impingement of safety related equipment was not part of this study, but was performed in the previous Limerick high energy line break analysis.
Our review has shown that the previously excluded piping meets the established project criteria (allowable stress and safe shutdown analysis requirements) for jet impingement loads on piping and pipe supports.
II.
DESCRIPTION OF REVIEW-A review of all previously postulated break locations was performed for both inside and outside Containment.
The break locations postulated are given in FSAR Section 3.6 (Ref. 2).
A complete review using piping layout drawings was performed for identification of target pipes.
320 piping breaks were reviewed.
1.
All potential piping targets with diameter equal to or greater than the ruptured pipe were identified.
Potential target piping was identified within a distance of 10 pipe diameters from the ruptured pipe.
The dia-meters were that of the ruptured pipe.
T-3/31 Page 1 of 5 w--
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.w A " cut off" distance of 10 pipe diameters was used for this study since at greater distance the jet impi ngement cone pressure on piping of equal to or greater than the diameter of the ruptured pipe has been shown to be insignificant.
This is true because there is little or no subcooling in the ruptured pipe relative to exit plane ambient _conditons.
The lack of subcooling results in some cone expansion in all the Limerick high energy break locations.
In order to expedite the target i.dentification process, a conservative jet cone of 45 degree half angle was initially assumed until calculated jet cone half angles were available.
Since 45 degrees is the largest calculated jet cone size for a ruptured pipe on Limerick, using this cone size assured that all potential target pipe was identified.
Initially 360 potential targets were identified.
The number of targets was reduced by reviewing in detail the more realistic geometry and calculated cone expansion angle using the actual thermodynamic condition in the ruptured pipe and the methodology of BN-TOP-2, Rev.
2, previously approved by the NRC (Ref. 3).
2.
A safe shutdown analysis was performed for each iden-tified potential target.
This safe shutdown analysis is consistent with previous work at Limerick.
The methodology followed for this analysis is set forth in Limerick Specification 8031-G-23.
This analysis and subsequent detailed review of the geometry showed that of the 360 potential targets identified in Step 1, only 24 targets were identified as piping that would be required to remain functional to assure safe shutdown.
(These lines are listed in Table I).
3.
Of the 24 lines required for safe shutdown, there were 12 symmetrical cases.
Symmetrical cases were piping with the same configuration (or minor variation) with similar r
support configuration such that the postulated jet load would result in similar pipe stress.
Out of the
-remaining 12 targets, 8 cases which would envelope the loads for all 24 targets were selected for stress analysis.
(These cases are shown in Table II).
The 8 cases were chosen to have the most severe jet impingement loading based upon closest distance to the ruptured pipe, the most severe jet impingement cone angle, and the worst support configuration for pipe loading from jet impingement.
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1.
Jet impingement loading on the target pipe was then calculated using the same methodology as previously used in Limerick analyses (FSAR Section 3.6, references 3.6-8 and 3.6-9).
4.
The loading combination used for the piping stress for the effects of jet impingement was:
P+DW+JI 11.5 Sy (Ref. 4) where the longitudinal pressure stress P
=
the bending stress due to the static weight DW
=
of the piping, including insulation and contents, concentrated masses, etc.
the bending stress due to the jet impinge-JI
=
ment loading the yield strength of the material at normal S
=
y operating temperature Pipe Stress Margin All the piping analyzed met the above criteria.
Table II shows the calculated stress for each of the eight cases analyzed.
There were no new loads generated on active components as a result of this analysis.
5.
Loading of pipe supports f rom piping impinged by the jet was evaluated using subsection NP of the ASME code.
The combination used was:
T+DW+JII max. allowable stress where the stress in the support resulting from the T
=
constraint of free thermal expansion of the piping.
the stress in the support resulting from the DW
=
static (dead) weight of the piping the stress in the support resulting from the JI
=
jet impingement loading on the piping.
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Stress Allowable The maximum allowable stress used was 29,400 PSI which is the. lesser of Sy and 0.42 Su.
In addition, axial stress is limited to 2/3' critical buckling and shear stress is limited to 0.42 Su.
The faulted load from the load capacity data sheet (LCD) was used for all standard supports.
Pipe Support Stress Margin Based upon the load combination and stress allowable outlined above, the average stress was found to be 10% of the allowable stress.
The largest actual stress 20% of the allowable stress.
III.
DISCUSSION OF COMBINATION OF SSE WITH JET IMPINGEMENT Inclusion of jet impingement loads in the faulted loading combination is not a licensing commitment basis for Limerick.
However, pursuant to the NRC staff request, the result of including jet impingement loading with other loads of the faulted loading combination is discussed.
Based upon the stress margin indicated by Table II and the section on pipe supports, II.5 above, it is apparent that margin exists in both the pipe and the supports for stresses due to SSE.
We feel confident that the piping and supports could be demonstrated to be acceptable for a postulated combination of jet impingement plus SSE based on the following reasons:
1.
Piping stresses are calculated for code compliance using the worst _ faulted load combination per FSAR, i.e.
DW+P+ Max (7 SSE'+DBA' or 7 SSE'y+AP' ) < 3Sm ( C 2 Sy).
In surveying the results of these calculations, we have found that SSE stresses do not contribute significantly in the total calculated piping stresses.
For the systems listed in Table II, the maximum calculated SSE stresses only account for about 20% of 1.5 Sy.
2.
The worst faulted load combination used for piping supports per the FSAR is W+T+ Max (VSSEZ+DBA4 or YSSEd+AP4).
This is calculated and compared with 0.9 Sy.
Because of the conservatism in this design, there is sufficient support capacity to allow combining SSE with jet impingement loads.
3.
Also, SSE stresses may be reduced if higher damping is used (1% damping is used as the design basis).
T-3/31 Page 4 of 5
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4.
It should be recognized that of the cases analyzed the worst case jet impingement loadings on piping required for safe shutdown are on stainless steels.
The ASME Code specifies relatively low yield strength for stain-less steel at operating temperature, but their tensile strengths are substantially higher.
IV.
CONCLUSION A review was performed of all target piping of equal or greater diameter than the source pipe.
An assessment of safe shutdown capability was made for all target piping.
For those pipes which were required for safe shutdown, the analysis showed the previously established stress criteria was met.
There were no hardware changes identified as a result of this review.
REFERENCES (1)
NRC Letter of February 26, 1985 from A.Schwencer to E.G.
Bauer.
(2)
Limerick FSAR, Section 3.6.
(3)
BN-TOP-2, Rev.
2, approved by NRC letter dated 6-17-74.
(4) " Functional Capability Criteria for' Mark II Piping" by E. C.
Rodabaugh, Sept. 1978 T-3/310 Page 5 of 5
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-O TABLE I TARGET LINES RE0'D FOR SAFE SHUrDOWN Case No.
(See Table II)
Systen Break No.
Source Pipe Target Pipe Recirc:
1 Loop A TE-296C 12" 12" DEA-ll2 3
12" DLA-112 Icop B TE-296C 12" 12" DEA-ll2 12" DIA-ll2 Core Spray:
Loop A IB-65L 12" DCA-320 on 12" DCA-318 LPCI "C" 5
Icop A IB-63L 12" DCA-320 on 12" DCA-318 LPCI "C" 4
Icop A IB-30L 12" DCA-320 on 12" DCA-318 LPCI "C" Icop B IB-65L 12" DCA-319 on 12" DCA-318 LPCI "B" Icop B IB-63L 12" DCA-319 on 12" DCA-318 LPCI "B" Icop B IB-30L 12" DCA-319 on 12" DCA-318 LPCI "B" Feedwater:
Icop A IB-100C 12" DLA-107 on 12" DIA-ll2 LPCI "B" (2 target) 12" DIA-107 on 12" DIA-ll2 LPCI "D" IB-100L 12" DIA-107 on 12" DLA-ll2 LPCI "D" 12" DIA-107 on 12" DIA-112 LPCI "B" Loop B IB-100C 12" DIA-108 on 12" DIA-ll2 LPCI "A" 12" DIA-108 on 12" DIA-ll2 LPCI "C" 2
IB-100L 12" DIA-108 on 12" DIA-112 LPCI "A" 12" DIA-108 on 12" DIA-ll2 LPCI "C" Residual Heat Ranoval:
LPCI ' Icop "B" IB-100L 12"DCA-318 on 12" DCA-319 Core Spray "B" IB-90L 12"DCA-318 on 12" DCA-319 Core Spray "B" IB-67L 12"DCA-318 on 12" DCA-319 Core Spray "B" 6
LPCI Icop "C" IB-100L 12"DCA-318 on 12" DCA-320 Core Spray "A" 7
IB-90L 12"DCA-318 on 12" DCA-320 Core Spray "A" 8
IB-67L 12"DCA-318 on 12" DCA-320 Core Spray "A" T-3/31
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TABIE II IES - JET IMPINGEMENT S'IUDY PIPIPC STRESS SUFMARY EOR SAFE SHUIDO6N TARGET LINES o
Case No.
Break ID Ce.:. No.
Allcwable P+DW&JI Percent 1.5 Sy (Psi)
Max. Ccznp. Stress (Psi)
Allow.
1 Hecirc.
1-10-07 23175 9264 40%
TE296C 2
Feedwater 1-10-07 23175 18719 81%
100L 3
lecire.
1-10-08 23175 7201 31%
TE296C 4
Core Spr.
1-10-08 23175 15126 65%
30L 5
Core Spr.
63L 1-10-08 23175 15386 66%
6 RHR LPCI l-20-02 23175 15741 68%
"C" 100L 7
RHR LPCI l-20-02 23175 13967 60%
"C" 90L 8
RHR LPCI l-20-02 23175 13616 59%
"C" 67L Pressure Stress, IM = Weight Stress, JI = Jet Impingenent Stress NOTES: 1) P
=
- 2) Sy = 15450 psi at 550*F based on code allowable ASME-Section III-1971 T-3/31