ML18139B265
| ML18139B265 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/09/1981 |
| From: | Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 943D-110879, IEB-79-02, IEB-79-2, NUDOCS 8104270452 | |
| Download: ML18139B265 (4) | |
Text
Vepco VIRGINIA ELECTRIC AND POWER C01f ANY, RICHMOND, VIRGINIA 23261
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- April Jg, 11.'981 RE SURRY POWER STATION UNIT 1 Serial No. 9430/110879 PSE&C/RHW, III:bwl Docket No ao=::2sD No. DPR-32 79-02 To assure operability of Seismic Categoy I piping systems in a seismic event, the program for meeting the requirements of I.E.Bulletin 79-02, "Pipe Support Base Plate Designs Using Concrete Expansion Anchors" was integrated with the piping re-analysis efforts associated with the NRC Order to Show Cause dated March 13, 1979, and I.E. Bulletin No. 79-14.
All pipe support base plates within this scope have been analyzed considering base plate fle~ibility. All anchor bolt design loads meet the factors of safety required by ttie Bulletin.
Base plates for new pipe supports required by the piping reanalysis and all existing pipe supports which are within the seismic boundary of the systems were analyzed for base plate flexibility. Existing base plates and anchor bolts which did not meet the design requirements were modified to meet the Bulletin require-ments.
Hilti bolts were installed with new base plates and existing anchor bolt repairs and modifications. These anchor bolts were installed in accordance with the manufacturer's requirements based upon on-site testing conducted at Surry Power Station by Hilti, Inc.
To ensure the adequacy of existing anchor bolts, an anchor bolt inspection and testing program was conducted. This program involved inspecting and tension testing one anchor belt per accessible base plate.
Where the first anchor bolt was found to be inadequate, the base plate was reanalyzed with the discrepant bolt missing and the remaining bolts inspected and tested to the new higher anchor bolt load to ensure adequacy of the anchorage system.
All inadequate anchor bolts identified were replaced. Test results show that 96.5 percent of the base plates were adequate to provide the required support anchorage.
Since all pipe support b~se plates have been reanalyzed and ver1fied to meet the design requirements and since the inspection and test results show that the anchor bolts are adequately installed to 'perform their intended function, we feel that the requirements of I.E.Bulletin 79-02 have been satisfied for Surry Unit 1.
Items one through six of the Bulletin are addressed below.
- 1. All pipe support base plates have been analyzed considering base plate flexibility and mod~fications made where the base plate or anchor bolts
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were foun*d inadequate by analysis. Finite element analysis was performed using the ANSYS computerprogram and United Computing Service base plate pre-processor program.
In some cases base plates were analyzed using Stone
&Webster Structural Division - Structural Evaluation (SD-STEP) Programs for base plates and drilled-in anchors, which allowed sufficient margin for flexibility and prying action.
2 *. The factors of safety required by the Bulletin, four for wedge type anchors and five for-shell type anchors, were used to determine the anchor bolt allowable loads for the reanalysis. All bas*e plates were reanalyzed to ensure that these factors of safety were met.
Where the factors of safety were not met by analysis, modifications were provided to ensure the appropriate factor of safety. The original design for anchor bolts at Surry was based*
on a. factor of safety of four*for all anchor bolts based on a design concrete strength of 3000 psi.
In conjunction with IE Bulletin 79-02, a concrete inspection program was performed to demonstrate a concrete strength o_f 4000 psi which would provide the factor of safety of five required by the Bulletin.
Thirty-two Windsor Probe Tests were performed at various locations throughout the plant (Surry Units l & 2) to provide data for the evaluation. The results of this program show a 95: percent confidence level of at least 4000 psi concrete.
Therefore, the reanalysis was based on 4000 psi concrete with the factors of safety of four and five required by the Bulletin.
- 3 *.
No special des.ign* requirements for the* anchor bolts to withstand cyclic loads were applied. Testing performed for the Owner's Group, the results of which were. submitted to the NRC in Technical Report TR-3501-1, Revision l "Summary *.
Report,. Generic Response to USNRC I&E Bulletin~No. 79-02, Base Plate/Concrete Expansion Anchor*Bolts 11 by. Teledyne Engineering Servi'ces, indicates.that cyclic.
loading on the anchors does not result in a general.reduction of the ultimate capacity of the anchor. Bolts for shell type anchors (Phillips Red Head Self-*
Drilling Anchors) were tightened snugly, but were not preloaded. Wedge anchors (Hilti bolts) were preloaded to the design allowable load.
- 4.
To ensure that the design requirements have been met for the installed anchor bolts, an inspection and testing program was conducted.
Under this program one anchor*bolt per accessible base plate was inspected and tension tested to at least the anchor bolt design load.
Anchor bolt installations wliich
~ere suspect based on the visual inspection,. were tension tested to five times the anchor bolt design load, to a maxi~um of 25 percent of the manufacture~~s ultimate, and evaluated for a factor of safety of five by determining the anchor capacity based on the results of the visual inspection, or by tension testing to five times the design load at greater than 25 perce~t ultimate.
When the anchor was found* to be inadequate as a result of the evaluation or slippage of greater than 1/16 11 under the tension test, the base plate. was reanalyzed with that bolt missing..
The remaining bolts on :the base plate were inspected and tested for adequacy under the higher redistributed load when the reanalysis was acceptable, or for the original design load when the loads could not be redistributed.
Inspection and test results showed that 96.5 percent of the base plates were acceptable~ All anchor bolts which were inadequate or damaged were replaced to ensure adequacy of the anchorage system.
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- 5.
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- In order to evaluate operabi"lfty of each Seismic Category I piping system, the anchor bolt inspection and test results were recorded on a system basis.
The system designations as shown in Volume 5, Table 15.2.1-1 of the Surry Final Safety Analysis Report were used in conjunction with the QA Category l piping Line Table to determine systems for I.E.Bulletin 70-02 purposes.
Of the l8 systems for which anchor* bolt inspections were performed, 16 of,
the systems had acceptance percentages greater than 95 percent. The acceptance percentages for the other two systems, Service Water and Diesel Muffler Exhaust, were 87.5 percent and 76.5 percent respectively. All base plates on these two systems were inspected and tested. Modifications were made to correct deficient base plates and thus ensure operability for all base plates. Final inspection and*test results are presented in Attachment l.
Piping _systems, 2 inches in diameter or less were originally designed by a chart analysis method.
To ensure adequacy of the base plates and anchor bolts in justifying operability of the small bore piping, a sampling pro~ram was condutted asspart of-the Surry Unit 2 program in response to the bulletin.
Results of this program:were submitted to the NRC in our Final Report on*
I.E. Bulletin No. 79-02 for Surry Power Station Unit 2 on August 4, 1980, Serial Number 943C/ll0879.
The small bore_piping base plates and anchor bolts were designed and installed by the same A/E and contractor that performed the work on the large* bore piping~. Therefore, based on the results of the Unit 2 program and the. Unit l large bore piping anchor bolt inspection and testing program, it is believed that a sufficient degree of conservation exists in the base plates and anchor bolts of the small bore piping to justify acceptance of this piping.
All Seismic Category I pipe supports on'.masoriry walls were resupported with-*
out* attachment to the masonry walls. Details of our inspections were provided in our letters of December 7,. 1979, Serial No. 943A/ll0879 and January 30,.
1980, Serial No. 943B/ll0879.
- 6.
Seismic Category I pipe supports using structural steel shapes anchored with concrete expansion anchor bolts were analyzed and inspected to the same criteria as pipe supports with base plates.
This letter represents our final report on I.E.Bulletin 79-02 for Surry Unit 1.
Should you have any question or require further information, please contact us.
Attachment cc:
Mr. Viccor Stello, Director Very*/~y yours~,~rI"
R. Sylvia ger - Nuclear Operations and Maintenance Office of Inspection & Enforcement Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation
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SYSTEM COMPONENT COOLING AND l
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'. NEUTRON SHIELD TANK COOLING, 251 441 31 276 134 1106 28 23 5
129 96.3 I
. CHEMICAL & VOLUME CONTROL 121 146\\ 2s I 59 59 I 53 6
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57
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- CONTAINMENT SPRAY 14 2i a I 21 4 ! 4 a
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4 100
, -RE_A_C-TO-R--CO-O-LA_N_T-----+-3-9-+-7-8+_ +l 1-----1--2-1--il--2-l -0--11--0-~-0--4-2-1-4-l-0-0-1 I
RESIDUAL HEAT REMOVAL 47 75 33* I 34 8
1 7
l -
1 0
8 100
- SAFETY INJECTION 122 217 40 j 60 117 95 22 17 5
112: 95.7 CONDENSATE AND FEEDWATER (INCLUDING AUXILIARY FEEDWATER)
SECONDARY VENT AND DRAIN (S.G. SLOWDOWN)
-* SERVICE WATER MAIN STEAM (INCLUDING HIGH PRESSURE STEAM DRAINS)
RECIRCULATION SPRAY PRIMARY VENT AND DRAIN SYSTEM REACTOR CAVITY PURIFICATION CONTAINMENT VACUUM BORON RECOVERY FIRE PROTECTION GASEOUS WASTE ELECTRICAL (DIESEL MUFFLER EXHAUST)
FUEL PIT COOLING I TOTAL 37 57 10 I 17 24 50 2 I 26 40 63 a 55 1.2 17 a 15 14 15 a 5
10 11 l
3 12 11 a 16
-3 4 a a
7 10 1 I 9
14 21 a f 7
I 39 6~
7 I 10 I
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2 21 33 2 :
15
, 842 1363191 i 651 i
30 27 22 18 8
6 2
10 10 7
7 1
l 4
4 0
0 14 12 47 47 17 11 16 15 521 446 3
3 a
30 100 4
3 1
21 95.5 2
1 1
7 87.5 I
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7 100
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4 100 a
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2 0
14 100 0
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47 TOO 6
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13 76~5 1
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16 100 75 57 18 503
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