ML13333A655
| ML13333A655 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/07/1988 |
| From: | Medford M SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.D.1, TASK-TM NUDOCS 8801120223 | |
| Download: ML13333A655 (29) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 M. 0. MEDFORD TELEPHONE MANAGER OF NUCLEAR ENGINEERING (818) 302-1749 AND LICENSING January 7, 1988 U. S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 NUREG-0737, Item II.D.1 - Performance Testing of Relief and Safety Valves San Onofre Nuclear Generating Station Unit 1
Reference:
Letter, Richard F. Dudley, NRC, to Kenneth P. Baskin, SCE, NUREG-0737, Item II.D.1 -
Performance Testing of Relief and Safety Valves, July 8, 1987 The referenced letter provided SCE with a request for additional information necessary for completion of the NRC review of the subject post-TMI item for San Onofre Nuclear Generating Station, Unit 1. Accordingly, enclosed with this letter is the requested information.
If you have any questions, please let me know.
Very truly yours, Enclosure cc:
D. Hickman, NRR Project Manager, San Onofre Unit 1 J. B. Martin, Regional Administrator, NRC Region V F. R. Huey, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3 6801120223 880107
(
PDR ADOCK 05000206 P
-ALe SONGS-1 RESPONSES TO NRC RELIEF AND SAFETY VALVE INFORMATION REQUEST
- 1. The response to NRC Question 12 in the licensee's 10-1-85 submittal refers to Table 3 in their 12-2-82 submittal.
Clarification of this table is required in order to avoid misinterpretation.
The following information should be provided:
- a. Clarify whether the listed values are maximum reactions considering all load cases or just the safety valve discharge case.
- b. Allowable values should be included in Table 3.
SCE Response:
- a. Table 3 of the 12-2-82 submittal has been revised to reflect the current pipe support configuration of the pressurizer discharge piping. The listed values (refer to Table 1.0 attached) are maximum reactions considering all load cases.
- b. Allowable values for pipe supports are listed in Table 3.0, Pipe Support Stresses (see response to Item 3).
The loads imposed by piping on the nozzles (originally included in Table 3 of the 12-2-82 submittal), were excluded from Table 1.0. The nozzle loads are now tabulated separately in Tables 4.0 through 4.3, including the allowables (see response to Item 4).
Note:
For all tables, please refer to the piping isometrics included in the Item 1 response for the Node Point or Data Point references.
Table 1.0 PIPE SUPPORT LOAD
SUMMARY
Sheet 1 of 3 NODE SUPPORT THERMAL THERMAL SEISMIC VALVE DESIGN POINT TYPE DEADWEIGHT (HOT)
(COLD)
(DBE) +
ACTUATION +
LOADS (+/-)
(LBS)
(LBS)
(LBS)
(LBS)
(LBS)
(LBS) 7 Y-Spring
-1367
-1367 Y-Snubber 912 6400 6400
-6400 X-Rigid 0
-1895 0
495 1200 1200
-3095 10 Z-Rigid
-573
-1029
-338 788 3500 2927
-5102 13 Y-Spring
-519
-519 X-Rigid 93 3660
-263 1095 4200 7953
-4556 16 Y-Snubber 658 1700 1700
-1700 Z-Rigid
-22
-1089 245 1278 4900 4878
-6011 X-Rigid
-537
-2857 1270 856 18500 17963
-21894 72 Y-Rigid
-197
-37 284 401 2700 2737
-2934 Z-Rigid
-304 566
-962 427 8000 8262
-9266 151 Y-Spring
-414
-414 152 Y-Snubber 802 4200 4200
-4200
Table 1.0 PIPE SUPPORT LOAD
SUMMARY
Sheet 2 of 3 NODE SUPPORT THERMAL THERMAL SEISMIC VALVE DESIGN POINT TYPE DEADWEIGHT (HOT)
(COLD)
(DBE) +
ACTUATION +
LOADS (+/-)
(LBS)
(LBS)
(LBS)
(LBS)
(LBS)
(LBS)
X-Rigid 0
-2340 0
549 3400 3400
-5740 Z-Rigid
-51
-515
-20 511 1600 1549
-2166 38 Y-Spring
-303
-303 X-Rigid
-33 4921 819 473 5400 10288
-5433 41 Y-Snubber 575 1800 1800
-1800 Z-Rigid
-88
-1840
-690 936 4900 4812
-6828 X-Rigid 451
-3340
-1811 771 13800 14251
-16689 73 Y-Rigid
-404 479 210 471 4000 4075
-4404 Z-Rigid 324 2417 1191 310 3200 5941
-2876 52 Y-Rigid
-277 2376 1369 1048 12200 14299
-12477 Z-Rigid 7
-6409
-292 766 7410 7417
-13812 57 Y-Snubber 1250 19520 19520
-19520 X-Rigid
-31 3208
-495 1186 11160 14337
-11686 58 Z-Rigid
-80
-8397 1467 2409 12270 13657
-20747
Table 1.0 PIPE SUPPORT LOAD
SUMMARY
Sheet 3 of 3 NODE SUPPORT THERMAL THERMAL SEISMIC VALVE DESIGN POINT TYPE DEADWEIGHT (HOT)
(COLD)
(DBE) +
ACTUATION +
LOADS (+/-)
(LBS}
(LBS)
(LBS)
(LBS)
(LBS)
(LBS) 153 Y-Spring
-780
-780 X-Rigid 45
-17590 6557 1310 14310 20912
-31855 65 Y-Rigid
-944 3623
-2189 1899 17770 20449
-20903 Z-Rigid 60 17754
-4301 1204 7370 25184
-11611
- 2. The response to NRC Question 18 in the licensee's 10-1-85 submittal is not considered complete. The following information should be included either in the existing tables or in a separate table:
- a. The results of all load case combinations,
- b. Allowable values for comparison.
SCE Response:
- a. Refer to Tables 2.0 and 2.1 - Stress Summary, for the results of all load case combinations on the piping upstream of the safety valves.
- b. Refer to Table 2.0 for allowable values.
TABLE 2.0 -
STRESS
SUMMARY
EQUATIONS 8 & 10 Piping Upstream of Safety Valves Equation 8 Equation 10 00 0
0 0
0 0
i LP 6 W Cj)+
Q/Sh 6TH TC o
/SA
.D.
tress Longit.
Weight Stress Thermal Thermal Stress Data (Wall)
Inten.
Pressure Weight
+
Ratio Hot Cold Ratio Pt.
Type (Thick.)
Factor Stress Stress Pressure Eq. 8 Stress Stress Eq. 10 I
Straight 3.500" 1.00 4,994 9,847 14,841
.885 16,517 2,416
.596 Pipe
(.438")
2 Elbow 3.500" 1.01 4,994 9,673 14,667
.875 17,019 2,775
.614
(.438")
3 Elbow 3.500" 1.01 4,994 9,092 14,086
.840 17,054 3,204
.615
(.438")
4 Valve 3.500" 1.00 4,994 7,106 12,100
.722 16,377 4,146
.591 Inlet
(.438")
5 Valve 6.625" 1.00 4,994 679 5,673
.338 2,275 709
.082 (1.000")
6 Valve 6.625" 1.00 2,957 398 3,355
.200 4,424 1,306
.159 Outlet
(.280")
25 Straight 3.500" 1.00 4,994 2,880 7,874
.469 14,322 2,922
.517 Pipe
(.438")
26 Elbow 3.500" 1.01 4,994 2,663 7,657
.456 13,778 3,221
.497
(.438")
27 Elbow 3.500" 1.01 4,994 2,439 7,433
.443 13,112 3,416
.473
(.438")
28 Valve 3.500" 1.00 4,994 2,046 7,040
.420 12,323 3,603
.445 Inlet
(.438")
29 Valve 6.625" 1.00 4,994 221 5,215
.311 1,699 527
.061 (1.000"1) 30 Valve 6.625" 1.00 2,957 580 3,537
.211 3,081 912
.111 Outlet
(.280")
Material - A312 TP316 Sc -
18,800 psi Sh @ 640 0 F -
16,760 psi SA -
1.25 Sc +.25 Sh -
27,690 psi Level "B" Upset Allowable -
1.2 Sb -
20,112 psi Level "C" Emergency Allowable -
1.8 Sh -
30,168 psi Level "D" Faulted Allowable - 2.4 Sh - 40,224 psi
TABLE 2.1 -
STRESS
SUMMARY
EQUATION 9 Piping Upstream of Safety Valves Equation 9 0
0 0 00 0
0 0
0 0
o S60BE 6DBE VA
& 80 (D
1.2 Sh 8 2,
+6 2
/1.8 Sh @
0 2.4 Sh 0.D.
Stress Weight Valve Weight Stress Weight +
Stress Weight +
Stress Data (Wall)
Inten.
+
+ Pressure Ratio SRSS of Pressure +
Ratio SRSS of Pressure +
Ratio Pt.
Type (Thick.)
Factor Pressure Stress Stress Stress
+ OBE Eq. 9U OBE & VA SRSS (OBE & VA)
Eq. 9E DBE & VA SRSS (DBE & VA)
Eq.
9F I
Straight 3.500" 1.00 14,841 1,810 11,304 12,986 16,651
.827 13,111 27,952
.926 17,216 32,057
.796 Pipe
(.438")
2 Elbow 3.500" 1.01 14,667 1,601 10,134 10,752 16,268
.808 10,870 25,537
.846 14,775 29,442 731
(.438")
3 Elbow 3.500" 1.01 14,086 1,321 8,369 7,717 15,407
.766
-7,829 21,915
.726 11,383 25,469
.633
(.438")
4 Valve 3.500" 1.00 12,100 384 2,941 1,022 12,484
.620 1,091 13,191
.437 3,113 15,213
.378 Inlet
(.438")
5 Valve 6.625" 1.00 5,673 107 577 1,703 5,780
.287 1,706 7,379
.244 1,798 7,471
.185 (1.000")
6 Valve 6.625" 1.00 3,355 227 122 2,546 3,582
.178 2,556 5,911
.195 2,548 5,903
.146 Outlet
(.280")
25 Straight 3.500" 1.00 7,874 1,986 14,681 19,030 9,860
.490 19,133 27,007
.895 24,034 31,908
.793 Pipe
(.438")
26 Elbow 3.500" 1.01 7,657 1,713 12,591 17,458 9,370
.465 17,541 25,198
.835 21,524 29,181
.725
(.438")
27 Elbow 3.500" 1.01 7,433 1,367 10,152 15,399 8,800
.437 15,459 22,892
.758 18,444 25,877
.643
(.438")
28 Valve 3.500" 1.00 7,040 487 3,785 12,414 7,527
.374 12,423 19,463
.645 12,978 20,018
.497 Inlet
(.438")
29 Valve 6.625" 1.00 5,215 120 932 1,691 5,335
.265 1,695 6,910
.229 1,930 7,145
.177 (1.000")
30 Valve 6.625" 1.00 3,537 294 1,890 3,961 3,831
.190 3,971 7,508
.248 4,388 7,925
.197 Outlet
(.280")
Material -
A312 TP316 Sc = 18,800 psi Sh @ 640F -
16,760 psi S
1.25 Sc +.25 Sh -
27,690 psi Level "B" Upset Allowable -
1.2 Sh = 20,112 psi Level "C" Emergency Allowable -
1.8 Sh -
30,168 psi Level "D" Faulted Allowable -
2.4 Sh = 40,224 psi
- 3. The licensee's responses did not provide a complete discussion of the supports analyses. Complete details of these analyses should be provided. This information should include but not necessarily be limited to the following:
- a. A discussion describing whether supports were explicitly included in the piping or were analyzed separately,
- b. The governing code,
- c. A complete description of the analytical techniques and computer codes (if applicable) used,
- d. A complete description of the load cases analyzed and the methods used to combine them,
- e. Tabulated results comparing maximum stresses and allowable values for all supports and all load cases.
SCE Response:
Pipe supports were modeled in the piping stress analysis, but were analyzed separately. Pipe support loads were obtained from the results of the piping analyses using computer programs "SAP V" and "SUPERPIPE."
The load cases that were considered in the piping analyses were Gravity (deadweight); Thermal-Hot (piping downstream of S/V is at 470*F); Thermal Cold (piping downstream of S/V is at 100*F); Seismic inertia (OBE and DBE); and Hydraulic transient load case due to S/V actuation.
Pipe support loads were combined as follows:
Design Loads = Gravity + (Envelope of Therm Hot and Therm Cold) +
Pipe supports were analyzed using the design loads as bases and were qualified in accordance with the SONGS-1 Seismic Reevaluation Criteria, ANSI B31.1 Code and AISC Standards. The pipe support qualification included evaluation of structural steel numbers, concrete expansion bolts, vendor catalog items, and welds.
Pipe support calculations have utilized one or more of the following items to evaluate the pipe supports:
A. Bechtel LAPD Plant Design Pipe Support Manual B. ME-240 (BISEPS-FRAME); structural analysis computer program or equivalent C. CE-742; bolts and base plate program or equivalent D. ME-210; welded attachment local stress analysis E. Hand Calculations F. Vendor Catalogs G. Design Guides and reference handbooks H. Westinghouse - PIPSAN computer code; structural analysis Table 3.0 (attached) lists the pipe supports including the type of support, design loads, weakest item in the load path, calculated stress value/weld size required, allowable stress value/actual weld size, and the size and type of vendor's components.
Sheet 1 of 2 TABLE 3.0 -
PIPE SUPPORT STRESSES Calculated Node Support Weakest Stress/Weld Allowable Stress/
Point TyDe Design Loads(1 )
Item Size Reo'd.
Actual Weld Size Remarks 7
Y-Spring
-1367 End Plate fy = 4.8 ksi Fv = 22.9 ksi Spring Hanger C&L Size 11. Type G Y-Snubber
+/-6400 Attachment Weld Req'd size =.05" Actual size =.25" Snubber Size PSA 3. Fig. 306 10 X-Rigid
+1200/-3095 Structural ft =
1.21 ksi Ft = 38.28 ksi Interaction =.58 Z-Rigid
+2927/-5102 Members fy =
1.47 ksi F = 19.14 ksi Qualified with fb = 21.18 ksi Fb = 38.28 ksi pipe support at Node Pt. 35 13 Y-Spring
-519 Weld-Beam Attach.
Req'd size =.007" Actual size =.25" Spring Hanger Two C&L Size 5.
TypeA 16 X-Rigid 7953/-4556 Concrete Tbolt = 6.22K Tall = 15.7K Interaction =.34 Z-Rigid 4878/-6011 Expansion Bolts Sbolt = 3.34K Sall =
7.9K Qualified with pipe support at Node Pt. 41 Y-Snubber
+/-1700 Weld-End Bracket Req'd size =.182" Actual size =.25" Snubber Size PSA -1 72 X-Rigid 17963/-21894 Weld Between Req'd size =.12" Actual size =.22" Qualified with Y-Rigid 2737/-2934 Structural pipe support at Z-Rigid 8262/-9266 Members Node Pt. 73 151 Y-Spring
-414 Baseplate fb = 3.75 ksi Fb = 19.14 ksi Spring Hanger Bending C&L Size 6 Type C 152 Y-Snubber
+/-4200 Structural fa =
1.08 ksi Fa = 17.68 ksi Interaction =.55 Member fb = 18.63 ksi Fb = 38.28 ksi Snubber Size PSA 3, Fig. 307 35 X-Rigid 3400/-5740 (See Node Pt. 10)
Z-Rigid 1549/-2166 Note:
(1)Design Loads are in Pounds (Reference - Table 1.0)
Sheet 2 of 2 TABLE 3.0 -
PIPE SUPPORT STRESSES Calculated Node Support Weakest Stress/Weld Allowable Stress/
Point Type Design Loads(1 )
Item Size Req'd.
Actual Weld Size Remarks 38 Y-Spring
-303 Load is relatively Spring Hanger small, no critical Grinnell Size 5 component.
Type C 41 X-Rigid 10288/-5433 (See Node Pt. 16)
Z-Rigid 4812/-6828 Y-Snubber
+/-1800 Weld-End Bracket Req'd size =.182" Actual size =.25" Snubber Size PSA-1 73 X-Rigid 14251/-16689 Y-Rigid 4075/-4404 (See Node Pt. 72)
Z-Rigid 5941/-2876 52 Y-Rigid 14299/-12477 Weld Req'd size =.17" Actual size = 312" Z-Rigid 7417/-13812 57 Y-Snubber
+/-19520 Concrete Tbolt = 3.03K Tall = 3.6K Interaction =.78 Expansion Bolts Sbolt = 1.69K sail = 6.SK 58 X-Rigid 14337/-11686 Weld f=
5.66 K/in Fall = 6.36 K/in Z-Rigid 13657/-20747 153 Y-Spring
-780 Concrete Tbolt =.52K Tall = 4K Interaction =.18 Expansion Bolts Sbolt =.36K Sall = 6.7K 65 X-Rigid 20912/-31855 Weld Req'd size =.17" Actual size =.25" Y-Rigid 20449/-20903 Z-Rigid 25184/-11611 Note:
(1)Oesign Loads are in Pounds (Reference -
Table 1.0)
- 4. The 12-2-82 submittal lists nozzle loads for the pressurizer and relief tank; however, allowable values were not included. The licensee should provide allowable nozzle loads and a detailed discussion of the analysis methods (WRC Bulletin, finite element analysis, etc.) used to confirm nozzle/vessel structural adequacy.
SCE Response:
Refer to Tables 4.0 through 4.3 for pressurizer and relief tank nozzle loads.
The allowable loads for the pressurizer nozzles are provided in Tables 4.0 through 4.2.
The allowable loads for the relief tank nozzle (a non-safety related equipment) are not available. The relief tank nozzle (10" diameter), was qualified based upon relatively low stresses at the piping/nozzle interface. Refer to Table 4.3 for stresses at the piping/nozzle interface.
The structural adequacy of the pressurizer nozzles is confirmed by complying with the allowable loads furnished to SCE by Westinghouse.
Table 4.0 PRESSURIZER NOZZLE LOADS (SAFETY VALVE)
FORCES (LBS)
MOMENTS (FT -
LBS)
DATA AXIAL SHEAR TORSION BENDING PT.
LOAD CASE Fx Fy Fz Mx My Mz O
DEADWEIGHT
-780
-450 570 1530
-1741 456 SEISMIC (OBE)(+)
180 203 178 144 184 191 VALVE ACTUATION(+)
1295 2559 2714 1369 2148 1788 TOTAL LOADS 2255 3212 3462 3043 4073 2435 PRIMARY LOADS (TOTAL) 2255 4722 3043 4745 ALLOWABLES 3310 15015 6400 5198 3"
PZR NOZZLE THERMAL (HOT) 570
-330 1150 1983 1620 2420 THERMAL (COLD) 170 190 400 144 478 127 TOTAL LOADS 570
-330 1150 1983 1620 2420 SECONDARY LOADS (TOTAL) 570 1196 1983 2912 ALLOWABLES 15740 10500 7583 6358 Notes:
- 1. Primary Load Combination:
Total Loads = Deadweight (Absolute sign)+ Seismic OBE + Valve Actuation Primary Loads (Total) = SRSS of Y and Z loads (Shear and Bending)
- 2. Secondary Load Combination:
Total Loads = Envelope of Thermal Hot and Thermal Cold Secondary Loads (Total) = SRSS of Y and Z loads (Shear and Bending)
Table 4.1 PRESSURIZER NOZZLE LOADS (SAFETY VALVE)
FORCES (LBS)
MOMENTS (FT -
LBS)
DATA AXIAL SHEAR TORSION BENDING PT.
LOAD CASE Fx Fy Fz Mx My Mz DEADWEIGHT 130
-270
-70
-228
-419 500 SEISMIC (OBE)(+)
167 231 181 169 213 390 VALVE ACTUATION(+)
808 1167 2281 3209 2616 1912 TOTAL LOADS 1105 1668 2532 3606 3248 2802 PRIMARY LOADS (TOTAL) 1105 3032 3606 4289 ALLOWABLES 3310 15015 6400 5198 3"
PZR NOZZLE THERMAL (HOT)
-530
-930
-290 2379
-483 1855 THERMAL (COLD) 200
-140
-220
-292 451
-315 TOTAL LOADS
-530
-930
-290 2379
-483 1855 SECONDARY LOADS (TOTAL) 530 974 2379 1916 ALLOWABLES 15740 10500 7583 6358 Notes:
- 1. Primary Load Combination:
Total Loads Deadweight (Absolute sign)+ Seismic OBE + Valve Actuation Primary Loads (Total) = SRSS of Y and Z loads (Shear and Bending)
- 2. Secondary Load Combination:
Total Loads = Envelope of Thermal Hot and Thermal Cold Secondary Loads (Total) = SRSS of Y and Z loads (Shear and Bending)
0 Table 4.2 PRESSURIZER NOZZLE LOADS (PORV)
FORCES (LBS)
MOMENTS (FT -
LBS)
DATA AXIAL SHEAR TORSION BENDING PT.
LOAD CASE Fx Fy Fz Mx My Mz 3
DEADWEIGHT
-125
-170
-8 13 1
257 SEISMIC (OBE)(+)
213 144 619 739 961 169 VALVE ACTUATION(+)
868 945 238 102 188 331 TOTAL LOADS 1206 1259 865 854 1150 757 PRIMARY LOADS (TOTAL) 1206 1527 854 1376 ALLOWABLES 3310 15015 6400 5198 3"
PZR NOZZLE THERMAL (HOT)
-894 546
-1295 1719 736 135 THERMAL (COLD)
-1070 440
-1124 1849 327
-192 TOTAL LOADS
-1070 546
-1295 1849 736
-192 SECONDARY LOADS (TOTAL) -1070 1405 1849 760 ALLOWABLES 15740 10500 7583 6358 Notes:
- 1. Primary Load Combination:
Total Loads = Deadweight (Absolute sign)+ Seismic OBE + Valve Actuation Primary Loads (Total) = SRSS of Y and Z loads (Shear and Bending)
- 2. Secondary Load Combination:
Total Loads = Envelope of Thermal Hot and Thermal Cold Secondary Loads (Total) = SRSS of Y and Z loads (Shear and Bending)
TABLE 4.3 - STRESS
SUMMARY
Pressurizer Relief Tank Nozzle Equation 8 Equation 10 (0
0 0
0 0
0 0
1 0LP (5W 03+ /Sh GTH 6TC or SA 0.D.
Stress Longit.
Weight Stress Thermal Thermal Stress Data (Wall)
Inten.
Pressure Weight
+
Ratio Hot Cold Ratio Pt.
Type (Thick.)
Factor Stress Stress Pressure Eq.
8 Stress Stress Eq. 10 71 Straight 10.750" 1.00 3,681 262 3,943
.263 12,522 7,901
.556 Pipe
(.365")
Equation 9 T
8 9
0 0
0 i
0 +(D UOBE ODBE TVA C11/1.2 Sh
)
)+2 @
3 /1.8 Sh 2
2
+7 2.4 Sh 0.D.
Stress Weight Valve Weight Stress Weight +
Stress Weight +
Stress Data (Wall)
Inten.
+
+ Pressure Ratio SRSS of Pressure +
Ratio SRSS of Pressure +
Ratio Pt.
Type (Thick.)
Factor Pressure Stress Stress Stress
+ OBE Eq. 9U OBE & VA SRSS (OBE & VA)
Eq. 9E DEE & VA SRSS (DBE & VA)
Eq. 9F 71 Straight 10.750" 1.00 3,943 472 2,554 8,800 4,415
.245 8,812 12,755
.472 9,163 13,106
.364 Pipe
(.365)
Material -
A106 GR. B Sc -
15,000 psi Sh @ 470oF -
15,000 psi A
1.25 Sc +.25 Sh - 22,500 psi Level "B" Upset Allowable -
1.2 Sh - 18,000 psi Level "C" Emergency Allowable - 1.8 Sh - 27,000 psi Level "D" Faulted Allowable - 2.4 Sh -
36,000 psi
- 5. The Licensee did not provide information on the maximum bending moment induced at the PORV outlet flange. This information is required to complete the evaluation of PORV operability.
SCE Response:
The maximum bending moment induced at the PORV outlet for each load case is tabulated in Table 5.0 (attached).
DRAFT EDavid:31-16q 09/01/87 5.0 MAXIMUM BENDING MOMENT AT PORV OUTLET Bending Moments (in -
1bs)
Node Point Loading Case MY Mz (My2 + Mz2 1/2 Deadweight 4
778 778 Thermal Hot 3,443 2,608 4,319 Thermal Cold 1,737 6,154 6,394 89 (CV-545)
Seismic OBE (+)
1,786 2,071 2,734 Seismic DBE (+)
4,397 3,290 5,491 Valve Actuation (+)
5,784 20,330 21,136 Deadweight 6
2,615 2,615 Thermal Hot 2,679 2,072 3,386 Thermal Cold 1,630 8,555 8,708 117 (CV-546)
Seismic OBE (+)
3,639 1,691 4,012 Seismic DBE (+)
13,560 8,101 15,795 Valve Actuation (+)
6,562 12,940 14,508
SAFETY/RELIEF VALVE DISCH PIPING N
Y
-RV-533 SOUTHERN CALIFORNIA EDISON CO.
SAN ONOFRE UNIT I W~1~z JOB NUMBER DRAWING NUMBER 03D0-083 SI-PSRV-0I SHT.
I OF 2 45'H 49/A
/
10 Qv2& 6?/
23 I/3 14 s 5 22 C -
2 'r-6 "2R6 117 45*g 4A.
o On N 9-20.IfE ffy DRAING UMBE REV.3 DECRPTO DAT BYCKDS1PR-1H.IO P/P/Nk-2*I'OMETR/
21ea
/*6 OF
-G'
SAFETY/RELIEF VALVE DISCH PIPING F
SSAFET-RV-632 SOUTHERN CALIFORNIA EDISON CO.
SAN ONOFRE*UNIT I z
JOB NUMBER DRAWING NUMBER 0310-083 SI-PSRV-OI SHT. 2 OF 2 I0 29
- OIMI ec a im.
oF'i 47 3
ONN Y
33 6
2-7S 27 -8 eR 2'-8 R 4
2*-8"It 42 RE V.
DESCRIPTION DATE BY ICHK'D S I-PSRV -0 1 SHT. 2 OF2T IDPP/A/
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- 6. NUREG-0737, Item II.D.1 requires that the plant-specific control circuitry be qualified for design-basis transients and accidents.
The licensee should provide information which demonstrates that the above requirement has been fulfilled. The Nuclear Regulatory Commission staff has agreed that meeting the licensing requirements of 10 CFR 50.49 for this circuitry is satisfactory and that specific testing per NUREG-0737 requirement is not required. Therefore, verify whether the PORV control circuitry has been reviewed and accepted under the requirements of 10 CFR 50.49.
If the PORV circuitry has not been qualified to the requirements of 10 CFR 50.49, provide information to demonstrate that the control circuitry is qualified per the guidance provided in Reg. Guide 1.89, Revision 1, Appendix E.
SCE Response:
The SONGS-1 PORV and PORV Block Valve control circuitries are qualified to the requirements of 10 CFR 50.49 and are included on the SONGS-1 EQ Master List.
- 7. In the Block Valve Adequacy Report dated November 17, 1983, the Licensee made a comparison of the design and operating conditions of the 2-in.
Anchor Darling gate valve used at San Onofre, Unit 1, and the 3-in.
Anchor Darling motor operated gate valve tested by EPRI and concluded that with the exception of the valve operators, the San Onofre block valve was similar to the test valve and the EPRI test results can be used as a basis for evaluating the in-plant block valves. It further concluded that, based on the test results, the San Onofre block valve was capable of performing its intended function. However, there are a few problems with the valve operation that the above report failed to address. According to the EPRI Block Valve Test Report, the original 3-in. Anchor Darling gate valve and its operator had been modified prior to the evaluation tests. The valve seat was redesigned to increase the seat area by eliminating the 1/8-in. raised face of the valve seat and the valve stem and bonnet were replaced. This modification was necessary because, during the initial checkout tests, the valve failed to close completely against full flow and noticeable seat damage and galling of the disc were discovered. In addition, the valve operator torque was increased by replacing the original Rotork 16-NAL operator with a larger Rotork 30-NAL operator. Thus, the EPRI test results actually represent that of the modified valve instead of the original 3-in. gate valve which was considered to be similar to San Onofre block valve. It is, therefore, open to question whether the EPRI test result are directly applicable to the San Onofre block valve unless additional justification is provided by the Licensee.
In regard to the seat galling problem, the San Onofre 1 Block Valve Adequacy report stated that a solution of this problem had not yet been determined and Anchor Darling was expected to conduct additional tests to define the cause of the problem and propose a resolution. So far, the Licensee has not indicated how the seat damage problem was solved.
In Figure 4-1 of the San Onofre 1 Block Valve Adequacy report, the valve resistance force of the San Onofre block valve was plotted against stem position for the opening and closing cycles. These resistance forces were compared with the valve operator output capacity to demonstrate the adequacy of the San Onofre 1 operator. The calculation of the valve resistance was not explained and no verification of the accuracy of the calculated results was provided. Furthermore, the comparison showed that the available torque in the San Onofre 1 operator was barely sufficient to close the valve under normal condition and in case the backup nitrogen system had to be used due to an interruption of the system air supply to the valve operator, the valve can only be closed within 5% of full closure. Under such circumstances, it is essential that the Licensee should provide evidence to demonstrate that the calculated valve resistance and the valve operator output are sufficiently accurate to ensure the proper closing of the block valve.
Our review indicates that the similarity between the San Onofre block valve and the modified test valve has not been established. The valve seat and stem damage problem has not been resolved and the accuracy of the valve thrust calculation has not been demonstrated. The operability of the San Onofre block valve cannot be demonstrated until the above problems are resolved.
SCE Response:
The November 17, 1983 SONGS-1 Block Valve Adequacy Report described the design of the SONGS-1 block valves and compared them to the valves tested by the EPRI Program. The adequacy report also acknowledged the galling problems experienced during the EPRI test and indicated that SCE would give consideration to any Anchor/Darling recommendations that resulted from their continuing review of the problem. Accordingly, the following information is offered.
As described in previous correspondence, the SONGS-1 block valves are actuated by a BS&B pneumatic actuator with a design output force of 9860 lbs, when full open and at an air pressure of 85 psig, and 7310 lbs., when full closed and at an air pressure of 85 psig. The force is lower when the 80 psig backup nitrogen is used, but this is acceptable as described later. The actuator closing force that was measured during the EPRI tests is the only parameter of concern in evaluating the adequacy of the block valves. Modifications that were done to the actuator(s) used during the EPRI tests were made to increase the closing torque and have no direct bearing on the adequacy of the valves.
Therefore, the SONGS-1 block valve actuator design output is appropriate to be used as part of the adequacy evaluation.
The galling problem seen during the EPRI tests is expected to occur at SONGS-1, if the block valves are exposed to similar conditions.
Technically, the definition of galling is the material transfer between two surfaces due to an adhesive process. Once galling is initiated, and the surface movement is repeated under high loads, the process continues and is exacerbated. The stellite seating surfaces of the EPRI test valve were galled after cycle testing and showed seat leakage. Apparently as a result of the galling, the test valve also exhibited an expected high seating load. The EPRI test valve had essentially been operating continuously under a high contact load, a high blowdown velocity and a high number of cycles. The test valve was cycled 141 times over the test period of 7 days.
The SONGS-1 valves have not and are not anticipated to operate under these conditions. Past maintenance of these valves has not revealed any transfer of material between the seat and disc during plant operation. The block valves have been closed due to leaking PORVs and during surveillance testing of the block valves every 92 days.
Therefore, it is concluded that the galling seen in the EPRI test valve will not occur at SONGS-1 unless similar operating conditions are experienced (i.e. high cycling frequency and high contact load).
Further the conditions experienced by the valves during the tests are not anticipated for postulated post-accident recovery operations at SONGS-1.
In the event that future Anchor/Darling vendor bulletins provide recommendations that will further minimize the likelihood of galling, SCE will give these recommendations due consideration.
With regard to the accuracy of the valve thrust calculation, the ratio method correlating the 3-inch EPRI test valve to the 2-inch SONGS-1 valve is an appropriate way to determine the necessary closing force for the SONGS-1 block valves. Since other assumptions remain constant, a ratio of closing forces based upon a ratio of valve seat closing areas is appropriate. However, in addition, both the galling seen as part of the EPRI test and the use of a conservative system pressure provide assurance that the SONGS-1 block valves will close. The EPRI test results were used to determine an appropriate SONGS-1 seat load by the use of a seat load based proportionally to the size of the SONGS-1 block valve seat and the closing differential pressure through the valve. As previously discussed, the EPRI test valve exhibited galling of the seating surfaces; therefore, it is expected that any proportionally calculated seat load would be conservative for a valve where similar galling is not expected.
Additionally, a conservative pressure of 2485 psig was used for the pressure seen by the block valve. The SONGS-1 PORVs are designed to control primary system pressure at 2200 psig and the block valves are designed for isolation of a postulated stuck-open PORV; therefore, the expected system pressure seen by the block valves would more appropriately be 2200 psig. SCE calculations of the effects of these conservatisms provide assurance that the valves will close under all design conditions and using either normal instrument air or backup nitrogen.
As seen by the previous discussion, there exists sufficient evidence and conservatism in the calculations to assure that the SONGS-1 block valves will be capable of closure when required. This is true whether the primary instrument air is used or the backup nitrogen.
- 8. In an overpressure transient resulting in valve actuation, the San Onofre Unit 1 safety valves are expected to discharge steam only. For the PORVs, both steam and liquid discharge are possible. In the thermal hydraulic analysis, the licensee only considered the steam discharge cases for the safety valves and PORVs. The licensee is requested to provide the calculations and results for water discharge through the PORVs.
SCE Response:
Based upon a conversation with the NRC staff on November 19, 1987, this question is understood by SCE to be related to our previous thermal-hydraulic analysis of the PORV/SV discharge piping. Given this understanding, SCE estimates that a reanalysis of the discharge piping, considering the effects of water discharge through the PORVs, can be completed and submitted to the NRC by June 1, 1988.