ML18079A938
| ML18079A938 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 08/22/1979 |
| From: | Stephens R Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7909200456 | |
| Download: ML18079A938 (2) | |
Text
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NRR Rdg. File - M. Groff DSS:MEB RDg. Fi1e Docket No.:
50-311.
- 3tOF Applicant:
Faci1 ity:
Public Serv*ice Electric & Gas Salem Unit 2 ll.UG. 2 2 1919.
SUBJECT:
SUMMARY
OF MEETING TO DISCUSS HIE SALEMUUNIT 2 RES90NSE TO IE BULLETIN 79~02 On August 17, 1979, the NRC staff met in Bethesda, Maryland, with representa..
tives of Public Service Electric & Gas to discuss the Salem Unit 2 response to IE Bulletin 79-02, "Pipe Support Base Plate Designs Using Concrete _
Expansion Anchor Bilts.
11 A list of meeting attendees is attach~d.
For purposes of responding-to this bulletin, PSE&G has joined an owner's group which*has contracted with Teledgne to perform certain generic testing of various anchor bolts. During this meeting PSE8iG described how it was using the results of the generic Teledyne testing for the specific anahor bo1ts in use at Salem Unit 2. Additionally, PSE&G described the status of the analyses and tests being performed by itself on the.anchor bolts installed ab Salem Unit 2 *
. ll.pproximately 10,QOO anchor bolts are used in Salem Unit 2 of which approximately 3,000 are on safety related systems. Of these safety related anchor bolts, 1 )295 are associated with 362 basep1ates:-. nearly a11 of which are floor mounted.
The remaining safety related anchor bolts are used ti!& connect structural steel directly to walls and ceilings *.I\\11 anchor bolts used fo Salem Unit 2 are of the wedge type, specifically, Hilti Quik-Bolts.
PSE&G stated that the original anchor bolt design criteria specified a minimum factor of safety of four against pullout and assumeddbasep1ate rigidity.
During its reevaluation of anchor bolt adequacy~ PSE&G is using analytical tools developed by Teledgne to account for baseplate flexibility.
To date, 136 baseplates have been analyzed with 9 requiring modification. Also, the applicant is using an elliptical shear-tension interaction curve wfth a minimum factor of safety of four against manufacturer's specified u1 ti mate bolt capacities.
(o/DCf2ZXYTo6 Prior to the issuance of IE Bulletin 79-02, PSES..G verified the correct Mlrt\\<J embedment depth of most of the 10,000 anchor bolts in Salem Unit 2 and corrected d the few which were deficient.
Due to some installation practices used by
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PSE&G, the verification of embedment depth for floor mounted anchor bolts is impractical. Therefore, for a sample of these floor mounted supports, PSE&G ie performing hydraulic pull tests to demonstrate a factor of safety of four against ppllout.
PSE&G ijticipates approximately 60-90 of these pull tests will be necessary to demonstnate a 95/95 confidence level for each safety
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related pip.1ng *system.
To date) 27 supports have been pulled with 26 passin9.
One support was considered a failure* due to excessive __ deflection (0.008 inch) although it did not ~pll from the floor.
Completion of-the remaining pull tests is scheduled for September 30, 1979.
The NRC staff stated the following positions to PSE&G:
(1)
The intent of IE Bulletin 79Q02 is to cover anchor bolts other than only those associated with baseplates~ such as the anchor bolts used to attach structural steel to walls and ceilings.
(2)
PSE&G should determine the extent and configuration of these safety related Wfi11 and cffie1ing mounted anchor bolts and provide this information to the NRC.
{3)
PSE&G should propose and implement for the ~al1 and ceiling mounted anchor bolts a testing program to satisfy the bulletin provisions and to include verification on a sampling basis that the wedges have been properly set.
(4) At this time, it is not necessary for PSE&G to demonstrate any specific value of preload on its anchor bolts other than what is necessary to correctly set th~ wedge.
This is a continuing generic issue whose resmlution depends upon additional experimental work.
Enclosure:
List of Attendees Randal M. Stepheae Mechanical Engineering Branch Division of Systems Safety OFFICE~
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SURNAME~
DATE~
NRC FORM 318 (9-76) NRCM 0240 Ul s. GOVERNMENT PRINTING OFFICEi 19711 -11211-1124