ML16340A383
| ML16340A383 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay, Diablo Canyon |
| Issue date: | 03/08/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7903150063 | |
| Download: ML16340A383 (12) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V SUITE 202 ~ WALNUTCREEK PLAZA 1990 N. CALIFORNIA BOULEVARD WALNUTCREEK, CALIFORNIA'4596 March 8, 1979 Docket Nos.
50-275 50-323
'acific Gas and Electric Company 77 Beale Street San Francisco, Cal ifornia 94106'ttention:
Mr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
The enclosed IE Bulletin= No. 79-02 is forwarded to you for action.
A written response is required.
- If you desire additional information regarding this matter, please contact this office.
Sincerely, R. H. Engelken Director
Enclosures:
l.
List of IE Bulletins Issued in the past 12 months cc w/enclosures:
R. Ramsey, PGSE ll. A. Raymond, PG&E J.
D. Morthington, PGSE g3 V903 igloo ~
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT LlASHINGTON, D.C.
20555 March 8, 1979 IE Bulletin No. 79-02 PIPE SUPPORT BASE PLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS Description of Circumstances:
While performing inservice inspections during a Harch-April 1978 refueling outage at Nil'Istone Unit I, structural failures of piping supports for'safety equipment were observed by the licensee.
Subsequent licensee inspections of undamaged supports showed a large percentage of the concrete anchor bolts were not tightened properly.
Deficiency reports, in accordance with 10 CFR 50.55(e), filed by Long Island Lighting Company on Shoreham Unit 1; indicate that design of base plates using rigid plate assumptions has resulted in underestima-tion of loads on some anchor bolts.
Initial investigation indicated that nearly fifty percent of the base plates could not be assumed to behave as rigid plates.
In addition, licensee inspection of anchor bolt installations at Shoreham has shown over fifty percent of the bolt installations to be deficient.
Vendor Inspection Audits by NRC at Architect Engineering firms have shown a wide range of design practices and installation procedures which have been employed for the use of concrete expansion anchors.
The current
'trends in the industry are toward more rigorous controls and verifica-tion of the installation of the bolts.
The data available on dynamic testing of the concrete expansion anchors show fatigue failures can occur at loads substantially below the bolt static capacities due to material imperfections or notch type stress risers.
The data also show low cycle dynamic failures at loads below the bolt static capacities due to joint slippage.
Action to be Taken by Licensees and Permit Holders:
For pipe support base plates that use concrete expansion anchor bolts in Seismic Category I systems as defined by Regulatory Guide 1.29, "Seismic Design Classification" Revision 1, dated August 1973 or as defined in the applicable FSAR.
1.
Verify that pipe support base plate flexibilitywas accounted for in the calculation of anchor bolt loads.
In lieu of supporting analysis justifying the assumption of rigidity, the base plates 10f 3
1
IE Bulletin No. 79-02 March 8, 1979 should be considered flexible if the unstiffened distance between the member welded to the plate and the edge of the base plate is greater than twice the thickness of the plate.
If the base plate is determined to be flexible, then recalculate the bolt loads using an appropriate analysis which will account for the effects of shear - tension interaction, minimum edge distance and proper bolt spacing.
This is to be done prior to testing of anchor bolts.
These calculated bolt loads are r'eferred to hereafter as the bolt design loads.
.2.
Verify that the concrete expansion anchor bolts have the following minimum factor of safety between the 'bolt design load and the bolt ultimate capacity determined from static load tests (e.g.
anchor bolt manufacturer's) which simulate the actual conditions of installation (i.e., type of concrete and its strength properties):
a.
Four - For wedg'e and sleeve type anchor bolts, b.
Five - For shell type anchor bolts.
3.
Describe the design requirements if applicable for anchor bolts to withstand cyclic loads (e.g. seismic loads and high cycle operating loads).
4.
Verify from existing gC documentation that design requirements have been met for each anchor bolt in the following areas:
(a)
Cyclic loads have been considered (e.g.
anchor bolt preload is equal to or greater than bolt design load).
In the case of the shell type, assure that it. is not in contact with the back of the support plate prior to preload testing.
(b)
Specified design size and type is correctly installed (e.g. proper embedment depth).
If sufficient documentation does not exist, then initiate a testing program that will assure that minimum design requirements have been met with respect to sub-,items (a) and (b) above.
A sampling technique is acceptable.
One acceptable technique is to randomly select and test one anchor bolt in each base plate (i.e.
some supports may have more than one base plate).
The test should provide verification of sub-items (a) and (b) above.
If the test fails, all other bolts on that base plate should be similarly tested.
In any event, the test program should assure that each Seismic Category 1 system will perform its intended function.
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IE Bulletin No. 79-02 h1arch 8, 1979 5.
All holders of operating licenses for power reactor facilities are requested to complete items 1 through 4 within 120 days of date of issuance of this Bulletin.
A reactor shutdown is not required to be initiated solely for purposes of this inspection above.
Maintain documentation of any sampling inspection of anchor bolts required by item 4 on site and available for NRC inspection.
Report in writing within 120 days of date of Bulletin issuance, to the Director of the appropriate NRC Regional Office, completion of your verifica-tion and describe any discrepancies in meeting items 1 through 4 and, if necessary, your plans and'chedule for resolution.
For planned action, a final report is to be submitted upon completion-of your action.
A copy of your report(s) should be sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
These reporting requirements do not preclude nor substitute for the applicable requirements to report as set forth in the regulations and license.
6.
All holders of construction permits for power reactor facilities are requested to complete items 1 though 4 for installed pipe support b'ase plates with concrete anchor bolts within 120 days of date of issuance of this Bulletin.
For pipe support base plates which have not yet been installed, document your actions to assure that items 1 though 4 will be satisfied.
Maintain documentation of these actions on site and available for HRC inspection.
Report 'in writing within 120 days of date of Bulletin issuance, to the Director of the appropriate NRC Regional Office, completion of your review and describe any discrepancies in meeting items 1 though 4 and, if necessary, your plans and schedule for resolution.
A copy of your report should be sent to the United States Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Construction Inspection, Washington, D.C.
20555.
Approved by GAO B180225 (R0072); clearance expires 7/31/80.
Approval was given under a blanket clearance specifically for identified generic pro bl ems.
Enclosure:
List of IE Bulletins Issued in Last Twelve t1onths 3 of 3
I Bulletin No. 79-02 March 8, 1979 LISTING OF IE BULLETINS ISSUED IN LAST TllELVE MONTHS Bulletin No.
78-03 78-04 78-05 78-06 78-07 Subject Potential Explosive Gas Mixture Accumula-tions Associated with BWR Offgas System Operations Environmental gual i-fication of Certain Stem Mounted'imit Switches Inside Reactor 'Containment Malfunctioning of Circuit Breaker Auxiliary Contact Mechanism-General Model CR105X Defective Cutler-
- Hammer, Type M Relays lilith DC Coils Protection afforded by Air-Line Respirators and Supplied-Air Hoods Date Issued 2/8/78 2/21/78 4/14/78 5/31/78 6/12/78 Issued To All BMR Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL, all class E and F
Research Reactors with an OL, all Fuel Cycle Facilities with an OL, and all Priority 1
Material Licensees 78-08 Radiation Level s from 6/12/78 Fuel Element Transfer Tubes All Power and Research Reactor Facilities with a Fuel Flement Transfer Tube and an OL.
78-09 BNR Drywell Leakage Paths Associated with Inadequate Drywell Closures 6/14/79 All BklR Power Reactor Facilities with an OL or CP Enclosure 2
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IE v.letin No. 79-02 March 8, 1979 LISTING OF IE BULLETINS ISSUED IN LAST TWELVE MONTHS Bulletin Subject No.
Date Issued Issued To 78-10 78-11 78-12 78-12A 78-13 Bergen-Paterson Hydraulic Shock Suppressor Accumulator Spring Coils Examination of Mark I Containment Torus Welds Atypical Weld Material in Reactor Pressure Vessel Welds Atypical Weld Material in Reactor Pressure Vessel Welds Failures In Source Heads of Kay-Ray, Inc., Gauges Models 7050, 7050B, 7051,
- 7051B, 7060,
- 7060B, 7061 and 7061B 6/27/78 7/21/78 9/29/78 11/24/78 10/27/78 All BWR Power Reactor Facilities with an OL or CP BWR Power Reactor Facilities for action:
Peach Bottom 2 and 3, Ouad Cities 1 and 2, Hatch 1, Monti-cello and Vermont Yankee Al-1 Power Reactor Facilities with an OL or CP All Power Reactor Facilities with an OL or CP All general and specific licensees with the subject Kay-Ray, Inc.
gauges 78-14 79-01 Deterioration of Buna-N 12/19/78 Components In ASCO Solenoids Environmental equal ifica-2/8/79 tion of Class IE Equipment All GE BWR facilities with an OL or CP All Power Reactor Facilities with an OL or CP Enclosure 2
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