ML20004B388
| ML20004B388 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 05/22/1981 |
| From: | Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Clark R, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8105280160 | |
| Download: ML20004B388 (14) | |
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VzmorNrA Er.ncrRrc AND power COMPANY Racmwown Vamorm a sons:
May 22, 1981 Mr. b rold R. Denton, Director Serial No. 311 Office of Nuclear Reactor Regulation N0/FMA:smv Attention:
Mr. Robert A. Clark, Chief Docket No. 50-339 Operating Reactors Branch No. 3 License No. NPF-7 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Gentlemen:
MULTI-STRUCTURE ARS REANALYSIS NORTH ANNA POWER STATION - UNIT 2 VIRGINIA ELECTRIC AND POWER COMPANY i
Condition 2.C.(13) of the Operating License NPF-7 Amendment No. 4, dated I
February 10, 1981, requires that the piping reanalysis for Multi-Structure Amplified Response Spectra (ARS) be completed by May 22, 1981.
We have completed the required reanalysis, and this letter summarizes the results.
The piping reanalysis for Multi-Structure ARS was performed in two phsses.
The Phase I and Phase II evaluation procedures are defined in letter, S rial No. 510 dated Juna 6,1980 and discussed in our letter, Serial No. 685 dated September 26, 1980.
'Ih e Phase I and II evaluation procedures are identical for North Anna Units 1 & 2.
Of the 78 computer-analyzed problems in Unit 2 l
affected by Multi-Structure ARS, 23 problems were found acceptable in the Phase I evaluation.
The results of the Phase I evaluation are presented in Table 1 in the same format as the Unit I results were presented in our letter, Serf s1 No. 685 dated September 26, 1980. As indicated in Table 1, 55 problems required the more detailed computer reanalysis as described in Phase II pro-cedures.
These 55 problems were assigned to priority groups, defined in our letter, Serial No. 872 dated October 28, 1980.
The North Anna Unit 2 upgrading of seismic piping systems affected by Multi-Structure ARS was consistent with our approach used to upgrade the seismic piping system in North Anna Unit 1 (Vepco letter NRC Serial No. 169 dated l
March 20, 1981).
We have completed all reanalysis, design, and installation l
of necessary modifications.
This is well beyond the requirements of the license condition.
Table 2 gives the status,'and Table 3 gives the number of modifications required, by the type of modification, for the Multi-Structure ARS effort.
Multi-Structure ARS Phase II detailed renalysis for Unit 2 was based upon conservative analysis methods. This has resulted in more pipe support modifi-cations than might have been necessary if more time had been available to devote to this ef fort.
Because of schedule restraints, no attempt has been made to " fine tune" the piping systems or use more sophisticated analysis methods, such as utilization of independent support motion.
8105280 D P
F Vinosus4 Es.sCTNIC AND POWEN COMPANY TO The extremely short schedule for reanalysis, requested by the NRC, and the short Spring outage of Unit 2 required that design of modifications be expedited.
Four supports had to be added to meet vendor seismic requirements for valves.
All supports were reviewed for updated loads from the stress analysis of piping systems with support function changes, if any. Our review indicates that all supports inside the containment met operability require-ments, and for supports outside the containment, 302 of 304 met operability
~
requirements. The operability criteria is given in Table 4.
In the course of final documentation review, if we find that any piping or support fails to meet the Technical Specifications Operability Criteria, we will take the appropriate action in accordance with the Station Technical Specifications.
Please contact us if you have any questions.
Very truly yours,
)Pr
(
\\
.' R. Sylvia Manager - Nuclear Operations and Maintenance Attachments cc:
Mr. James P. O'Reilly, Director Office of Inspection and Enforcement Region II Atlanta, Georgia 30303 I
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t TABLE 1 - N.A. UNIT NO. 2 PIPING PHASE I BASIS FOR PROBLEM DESCRIPTION CATECORY ACCEPTABILITY MSK-103J COMPONENT COOLING:
A Piping problem has no modes
(
Return from RPV Shroud Coolers whose frequencies fall within regions where the alternate MSK-107B SAFETY INJECTION:
A ARS exceeds the design basis 4
Discharge of R.W.S.T. "TK-1" ARS t
A Combined Flow to R.C. Icops "A",
"3",
& "C" (outside) 5 11715-MSK-10'/G AUXILIARY FEEDWATER:
A Flow to R.C. Heat Exchanger "1B" 11715-MSK-111AF SAFETY INJECTION A
Flow from LHSI Pump "1A" to Charging Pumps "A", "B"
& "C" MSK-111B Safety Injection A
Original Analysis used enveloped ARS MSK-111C Safety Injection A
NOTE:
Category A indicates acceptability by Phase I review.
j Category B indicates that Phase II reanalysis is required.
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P;g2 2 TABLE 1 - N.A. UNIT NO. 2 PIPING PHASE I BASIS FOR PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY MSK-102K STEAM GEN WET LAY-UP:
A Affected modes have negligible Discharge from "A" Steam Generator response increases due to in-significant increases in MSK-102L STEAM GEN. WET LAY-UP:
A acceleration or low mass Discharge from "C" Steam Generator participation MSK-105C SERVICE WATER:
A Flow to the Containmer.t Recire.
Spray Heat Exchanger "D" MSK-107C SAFETY INJECTION:
A Discharge of R.W.S.T. "TK-1" MSK-107D QUENCH SPRAY:
A "A" Pump Discharge to Containment Pump MSK-111F CHARGING:
- Piping Upstream of Regenerative Heat Exchanger A
MSK-111C SEAL RETURN:
A Combined Return "A",
"B",
& "C" RCP's (Outside)
MSK-114K RECIRCULATION SPRAY:
A l
"B" Heat' Exchanger to Spray Header l
11715-MSK-121D CONTAINMENT VACUUM:
A Line to Air Ejector /Used in Startup 11715-MSK-118A COMPONENT COOLING:
A Supply to RCP "C" i
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b TABLE 1 - N. A. UNIT NO. 2 4
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i PIPING PHASE I BASIS FOR PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY l
t MSK-102M STEAM GEN. WET LAY-UP A
Affected modes exhibit signi-f Discharge from "B" Steam Generator ficant ncreases in individual modal response, but effects on (
MSK-103AQ SEAL INJECTION:
A combined analysis results will j Supply to RCP "C" be negligible.
MSK-104G QUENCH SPRAY j
"A" Pump Discharge to Contaimnent Pump A
MSK-105F SERVICE WATER:
A Return from Recirculation Spray Heat
[
Exchanger "D" MSK-103AC SEAL INJECTIOU:
A Modal response increases have j
Supply to RCP "B" moderate effects on combined results. No equipment is j
MSK-103AS SEAL INJECTION:
A present.
Supply to'RCP "A" i
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4 4
Prga 4 TABLE 1 - N.A. UNIT NO. 2 L
PIPING PHASE I BASIS FOR I
PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY MSK-101A MAIN STEAM:
B Acceptability to be deter-Main Steam to Turbines mined in the Phase II effort.
MSK-101B MAIN STEAM:
B Main Steam from "A" Steam Generator l
MSK-101C MAIN STEAM:
B Main Steam from "B" Steam Generator 4
MSK-101D MAIN STEAM:
B Main Steam from "C" Steam Generator MSK-102A FEEDWATER:
B
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Feedwater to "A" Steam Generator MSK-102B FEEDWATER:
B Feedwater to "B" Steam Generator MSK-102C FEEDWATER:
B Feedwater to C" Steam Generator MSK-102D FEEDWATER:
B Feedwater to Steam Generators MSK-103B COMPONENT COOLING:
B j
Return from Recire. Air Cooling MSK-103C COMPONENT COOLING:
B Supply to "B" RCP I
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Pcg3 5 p.BLE 1 - N.A. UNIT NO. 2 PIPING PHASE I BASIS FOR PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY MSK-103C COMPONENT COOLING:
B Acceptability to be deter-Supply to "B" RCP mined in the Phase II effort.
MSK-103D COMPONENT COOLING:
B Supply to "A" RCP MSK-103E COMPONENT COOLING:
B Supply to "C" RCP MSK-103F COMPONENT COOLING:
B Supply to "A" RHR Heat Exchanger MSK-103G COMPONENT COOLING:
B Supply to "B" P.HR Heat Exchanger MSK-103H COMPONENT COOLING:
B Return from Shread Cooler to Containment MSK-103K COMPONENT COOLING:
B Return from "D" RCP MSK-103L COMPONENT COOLING:
B Return from "A" RHR Heat Exchanger MSK-103M COMPONENT COOLING:
B Return from "B" Heat Exchanger MSK-103AA SAFETY INJECIION:
B Hot Leg Injection from Containment
Pzg2 6 TABLE 1 - N.A. UNIT NO. 2 PIPING PHASE I BASIS FOR PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY MSK-103AJ SAFETY INJECTION:
B Acceptability to be deter-Hot Leg Injection from Containment mined in the Phase II ef fort.
MSK-103BB SAFETY INJECTION:
B Cold Leg Injection from Containment l
MSK-103BD SAFETY INJECTION:
B Cold Leg Injection from Containment MSK103BH LOOP FILL HEADER:
B Supply to R.C. Imops "A", "B"
& "C" i
MSK-103BQ INSTRUMENT AIR:
B Suction from Containment (Inside)
MSK-104B SAFETY INJECTION:
B L.H.S.I. Pump Discharge to Containment and Charging Pump Suction MSK-104E RECIRCULATION SPRAY:
B "A" Pump Discharge to Containment (Outside) 4 MSK-104F QUENCH SPRAY:
"B" Pump Discharge to Containment (Outside)
B MSK-104H RESIDUAL HEAT REMOVAL:
B R.H.R. to R.W.S.T.
"TK-1" MSK-105A SERVICE WATER:
B Flow to Containment Recire. Spray Heat Exchangers
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TABLE 1 - N.A. UNIT NO. 2 PIPING PHASE I BASIS FOR PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY MSK-105B SERVICE WATER:
B Acceptability to be deter-Flow from Containment Recire. Spray Heat mined in the Phase II effort.
Exchangers MSK-107E SAFETY INJECTION:
B L.H.S.I. L' ump Discharge from Charging i
Pumps MSK-107H QUENCH SPRAY B
"B" Pump Discharge to Containment (Outside)
MSK-111E SEAL INJECTION:
B Combined Flow to RCP A",
"B",
& "C" MSK-111N SEAL RETURN:
B I
combined Return "A", "B"
& "C" l
MSK-111Y CHARGING:
l Piping Upstream of Regenerative Heat Exchanger B
MSK-111AC LETDOWN LINES:
B Piping Downstream of Regenerative Heat Exchanger 1
i MSK-114B QUPNCH SPRAY:
B l
"E Pump Discharge to Spray Header MSK-114D RECIRCUIATION SPRAY:
B "D" Cooler to Spray Header i
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TABLE 1 - N.A. UNIT NO. 2 1
PIPING PHASE I BASIS FOR PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY MSK-114E QUENCH SPRAY:
B Acceptability to be deter-
"A" Pump Discharge to Spray Header mined in the Phase II effort.
?
I MSK-114F RECIRCULATION SPRAY:
B "A" Pump Discharge to "D" Coolar F
MSK-114G RECIRCULATION SPRAY:
B "B" Pump Discharge to "C" Cooler MSK-114L RECIRCULATION SPRAY:
B "A" Heat Exchanger to Spray Header MSK-114M RECIRCULATION SPRAY:
B "C" Cooler to Spray Header SEPIA-103A6 COMPONENT COOLING:
B T'aermal Barrier of RCP SEPIA-103A6, A7 STEAM GENERATOR BLOWDOWN:
B From Steam Generators to Penetretion 11715-MSK-111A CHEMICAL AND VOLUME CONTROL:
B j
Supply to R.W.S.T.
11715-MSK-1115 SAFETY INJECTION:
B Low Head to High Head Cross-Connect "A" Pump (Outside) 4 e
i e
Paga 9 e
TABLE 1 - N.A. UNIT NO. 2 4
I PIPING PHASE I BASIS FOR I
PROBLEM DESCRIPTION CATEGORY ACCEPTABILITY 11715-MSK-111C SAFETY INJECTION B
Acceptability to be determined Iow Head to High Head Cross-Connect "B" in the Phase II effort, j
Pump R.W.S.T. Suction 11715-MSK-118B COMPONENT COOLING:
B Supply to RCP "A" and "B" 11715-MSK-118E COMPONENT COOLING:
B Return from RCP "A" and "B" I
11715-MSK-118F COMPONENT COOLING:
B
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Return from RCP "C" 11715-MSK-118G COMP. COOLING & SERVICE WATE1:
B Return from Recirculation Air Cooling 4
11715-MSK-118H COMP. COOLING & SERVICE WATER:
B Supply to Recirculation Air Cooling 11715-MSK-118K COMPONENT COOLING:
B Main Supply to Unit 2 Containn.ent 11715-MSK-118N COMPONENT COOLING:
B Main Return from Unit 2 Containment I
_ TABLE 2 NORTH ANNA UNIT 2 MULTISTRUCTURE ARS SUPPORT MODIFICATION STATUS Total No.
Stress Total No.
Total Supports Total Supports Total Supports Total Supports Stress Problems of Evaluated Not Ident. Req.
Ident. Reg.
Completed by Problems Evaluated Supports Requiring Mod.
Func. Changes Modification Construction i
Inside 1
Containment Groups 1-5 19 19 (15) 278 257 12 9
21 Croups 6-8 15 15 (12) 182 173 4
5 9
Outside Containment i
Groups 1-5 12 12 (9) 219 192 7
20 27 Groups 6-8 9
9 (6) 85 62 16 7
23 i
Notes:
(1) Final Documentation of all calculations is scheduled to be completed by July 31, 1981.
(2) Our review indicates that 459 of 460 supports inside the containment, and 302 of 304 outside the containment met operability requirements.
(3) The number in parenthesis represents the number of stress problems
]
requiring no support functional changes.
l (4)
Priority Groups are defined in our letter Serial No. 872 dated October 28, 1980.
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5 TABLE 3 NORTH ANNA UNIT 2 MULTISTRUCTURE ARS SUPPORT MODIFICATION TYPE Number of Modifications Groups 1-5 Groups 6-8 Groups 1-5 Groups 6-8 Type of Inside Inside Outside Outside Modification Containment Containment Containment Containment Total A. Base Plates 1.
Add gussets or bolts 2
2 6
2 12 B.
Pipe Supports 1.
Add, replace, or relocate strap, u-bolt, clamp, or spring 2
2 3
1 8
2.
Modify member welded to piping 0
0 2
2 4
3.
Replace or Reinforce member 4
0 1
2 7
4.
Add displacement limiting 0
0 3
0 3
restraint in MSVH 5.
Change hanger function 8
3 0
11 22 C.
Add Shim 0
1 0
0 1
D.
Add Snubber 5
1 4
3 13 E.
Delete Snubber 0
0 0
2 2
F.
Change Snubber 0,
0 8,
O_
8, Total 21 9
27 23 80 Note:
Final Documentation of all calculations is scheduled to be completed by July 31, 1981.
TABLE 4 NORTH ANNA UNIT 2 MULTISTRUCTURE ARS OPERABILITY CRITERIA O~ erability review shall be performed for the Design Basis Earthquake (DBE) p loadcase. Non-linear static and dynamic analysis is permissible for operability review.
Maximum Allowable Stress in Pipe 2.4 S Class 2 & 3 or 3.0S, Class 1_
h (Note 1)
Maximum Allowable Stress in Pipe Lessor of.7 Ultimate Stress or 1.2 Support & Base Plate Yield Stress (Note 2)
Maximum Allowable Bolt Tensile Load 1/2 Ultimate Pullout Load (Note 3)
Maximum Load on Snubber One-time Allowable Load Rating given in Grinnell Catalog PH-74 NOTES:
1)
Based on Subsection NB-3600 (Class 1) and NC-3600 (Class 2 & 3) of the AMSE Section III Boiler & Pressure Vessel Code 1980.
2)
Based on Appendix F, Article F 1370 of the ASME Section III Boiler &
Pressure Vessel Code 1977 and Addenda up to summer 1979.
3)
Based on I & E Bulletin 79-02.
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