ML19291C311

Forwards Updated Response to IE Bulletin 79-02,Revision 2, Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts. Min Safety Factor Used for Const of Facility Is Five.Unit Designed Using DBE Criteria

ML19291C311
Person / Time
Site:	Oyster Creek
Issue date:	12/07/1979
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-79-02, IEB-79-2, NUDOCS 8001240169
Download: ML19291C311 (8)

Text

.

7s Jersey Central Power & Light Company Madison Avenue at Punch Bowl Road Morristown, New Jersey 07960 (201)455-8200 December 7, 1979 Mr. Boyce H. Grier, Director Office of Inspection and Enforcement Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406

Subject:

Oyster Creek Nuclear Generating Station Docket No. 50-219 IE Bulletin No. 79-02 Ref, a: Teledyne Engineering Services Technical Report TR-3501-1 Dated August 10, 1979 The purpose of this letter is to update our response to Bulletin 79-02 and respond to the directives set forth in Revision 2 of that bulle-tin.

Previous reports were submi tted on July 6 and August 3,1979 These reports responded to Revisions 0 and I of Bulletins 79-02, and they also addressed items 1 and 3 of Revision 2.

Our responses to the specified action items in Bulletin 79-02, Revision 2, are given in Attachment 1.

I Very truly yours, h m :=- ,

[ Donald A. Ross, Manager

1. Generating Stations-Nuclear if Attachment CC: NRC Office of Inspection and Enforcement Division of Reactor Operations inspection Washington, DC 20555 1795 001 Jersey Central Power & Light Company is a Member of the Gener e 3 so01 ado hc Utd: ties Systern ic$

NRC Action item No. 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 wedge and sleeve type anchor bolts,

b. Five - For shelI type anchor bol ts.

The bolt ultimate capacity should account for the effects of shear-tension interaction, minimum edge distance and proper bolt spacing.

If the minimum factor of safety of four for wedge type anchor bolts and five for shell type anchors cannot be shown then Justification must be provided. The Bulletin factors of safety were intended for the maximum support load including the SSE. The NRC has not yet been provided adequate justificaticn that lower factors of safety are acceptable on a long term basis. Lower factors of safety are allowed on an Interim basis by the provisions of Supplement No. I to lE Bulletin No. 79-02. The use of reduced factors of safety in the factored load approach of ACI 349-76 has not yet been accepted by the NRC.

Response to Action item No. 2 The minimum factor of safety for the anchor bolts (Phillips-shell) primarily used for the construction of Oyster Creek is five (5). Oyster Creek was de-signed and seismically analyzed using OBE criteria. However, in order to apply SSE criteria to the analysis, the seismic portion of the loads need to be doubled. The seismic loads on the supports in the Reactor Building were con-servatively decermined based on the response, of the highest elevation of the building without respect to actual locations. After analyzing the locations of the systems covered by this Bulletin and incorporating SSE criteria, re-suits indicate that the minimum safety factor of five (5) is maintained for the systems in the Reactor Building.

Analysis of the piping systems in the Turbine Building were also based on OBE criteria. The seismic loads on the supports were determined based on a ground level response. In the Turbine Building, there is only one (1) system, the Emergency Service Water Svstem, which is covered by the Bulletin. Analysis of this system using SSE criteria is in progress, and this involves approximately 30 hangers. This analysis is expected to be complete in approximately four (4) weeks. Repairs or modifications shall be performed on any hanger where the analytical results indicate that the minimum safety factor of five (5) is not maintained, although we do not expect any bangers to fall below the safety fac-tor of five (5). Completion of such modifications will be scheduled prior to the end of our refueling outage, scheduled to begin January 5, 1980.

1795 002 M

L

NRC Action item No. 4 Verify from existing QC 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 oa that base piste should be similarly tested.

In any event, the test program should assure that each Seismic Category I system will perform its intended function.

The preferred test method to demonstrate the bolt preload has been accomplished is using a direct pull (tensile test) equal to or greater than design load.

Recognizing this method may be difficult due to accessibility in some areas an alternative test method such as torque testing may be used. If torque testing is used it must be shown and substantiated that a correlation between torque and tension exists. If manufacturer's data for the specific bolt used is not available, or is not used, then site specific data must be developed by qualification tests.

Bolt test values of one-fourth (wedge type) or one-fif th (shell type) of bolt ultimate capacity may be used in lieu of Individually calculated bolt design loads where the test value can be shown to be conservative.

The purpose of Bulletin No. 79-02 and this revision is to assure the operability of each seismic Category I piping system. In all cases an evaluation to con-firm system coerability must be performed. If a base plate or anchor bolt failure rate is identified at one unit of a multi-unit site which threatens operability of safety related piping systems of that unit, continued operation of the remaining units at that site must be immediately evaluated and reported to the NRC. The evaluation must consider the generic applicability of the identified failures.

Appendix A describes two sampling methods for testing that can be used.

Other sampling methods may be used but must be justified. Those options may be selected on a system by system basis.

17"95 003'

NRC Action item No. 4 (Continued)

Justification for omitting certain bolts from sample testing which.are in high radiation areas during an outage must be based on other testing or analysis which substantiates operability of the affected system.

Bolts which are found during the testing program not to be preloaded to a load equal to or greater than bolt design load must be properly preloaded or it must be shown that the lack of preloading is not detrimental to cyclic loading capability. Those licensees that have not verified anchor bolt preload are not required to go back and establish preload. However, additional information should be submitted which demonstrates the effects of preload on the anchor bolt ultimate capacity under dynamic loading. If it can be established that a tension load on any of the bolts does not exist for all loading cases then no preload or testing of the bolts is required.

If anchor bolt testing is done prior to completion of the analytical work on base plate flexibility, the bolt testing must be performed to at least the original calculated bolt load. For testir.s purposes factors may be used to conservatively estimate the potential increase in the calculated bolt load due to base plate flexibility. After completion of the analytical work on the base plates the conservatism of these factors must be verified.

For base plate supports using expansion anchors, but raised from the supporting surface with grout placed under the base plate, for testing purposes it must be verified that leveling nuts were not used. If leveling nuts were used, then they must be backed off such that they are not in contact with the base-plate before applying tension or torque testing.

Bulletin No. 79-02 requires verification by inspection that bolts are properly installed and are of the specified size and type. Parameters which should be included are embedment d'oth, thread engag ement, plate bolt hole size, bolt spa.o , edge distance to the side of a concrete member and full expansion of the shell for shell type anchor bolts.

If piping systems 2 1/2-inch in diameter or less were computer analyzed then they must be treated the same as the larger piping. If a chart analysis method was used and this method can be shown to be highly cei.-

servative, then the proper installation of the base plate and anchor bolts should be verified by a sampling inspection. The parameters inspected should include those described in the preceding paragraph. If small diameter piping is not inspected, then justification of system operability must be provided.

Response to Action item No. 4 Reference a is being included as a part of our response to the Bulletin, and has previously beca submitted by the 14-member Utility Group (Teledyne) by let-ter from R. Ciatto of Teledyne to S. K. Chaudhary and L. E. Tripp of Region I, dated September 7,1979 JCPSL is a member of this group.

Conclusions f rom the report indicate that " concrete expansion anchor bolts which are not preloaded do not deteriorate when subjected to cyclic loading". Also,

" Cyclic loading of anchor bolts does not decay the ultimate capacity of the. anchor".

1795 004 L

NRC Action item No. 5 Determine the extent that expansion anchor bolts were used in concrete block (masonry) walls to attach piping supports in Seismic Category I systems (or safety related systems as defined by Revision 1 of IE Bulletin No. 79-02). If expansion anchor bolts were used in concrete walls:

a. Provide a list of the systems involved, with the number o? supports, type of anchor bolt, line size, and whether these supports are acces-sible during normal plant operation.

b. Describe in detail any design consideration used to account for this type of installation.

c. Provide a detailed evaluation of the capability of the supports, including the anchor bolts, and block wall to meet the design loads.

The evaluation must describe how the allowable loads on anchor bolts in concrete block walls were determined and als.o what analytical method was used to determine the integrity of the block walls under the imposed loads. Also describe the acceptance criteria, including the numerical values, used to perform this evaluation. Review the deficiencies identified in the Information Notice on the pipe supports and walls at Trojan to determine if a similar situation exists at your facility with regard to supports using anchor bolts in concrete block walls,

d. Describe the results of testing of anchor bolts in concrete block walls and your plans and schedule for any further action.

Response to Action item No. 5 Af ter reviewing all piping supports addressed by the Bulletin, we have determined that there are no instances of expansion anchor bolts used in concrete block (masonry) walls.

17951005'

NRC Action Item No.,6 Determine the extec; taat pipe supports with expansion anchor bolts used structural steel shapes instead of base plates. The systems and lines re-viewed must be consistent with the criteria of IE Bulletin No. 79-02, Revision 1. If expansion anchor bolts were used as described above, verify that the anchor bolt and structural steel shapes in these supports were included in the actions performed for the' Bulletin. If these supports cannot be verified to have been included in the Bulletin actions:

a. Provide a list of the systems involved, with the number of supports, type of anchor bolt, line size, and whether the supports are acces-sible during normal plant operation.

b. Provide a detailed evaluation of the adequacy of the anchor bolt design and installation. The evaluation should address the assumed distribution of loads on the anchor bolts. The evaluation can be based on the results of previous anchor bolt testing and/or analysis which substant!ates operability of the affected system.

c. Describe your plans and schedule for any further action necessary to assure the affec cd systems meet Technical Specifications operability requirements in the event of an SSE.

Response to Action item No. 6 After reviewing all systems addressed by the Bulletin, a list of the systems with hangers using structural steel shapes other than flat baseplates has been compiled. Attachment i lists these systems, with the number of supports, type of anchor boic, line size and whether the supports are accessible during normal plant operation.

The results of our previous anchor bolt / hanger analyses and inspection indicates that only 1.1% (4 out of 353 hangers) did not meet the criterion of maintaining a minimum safety factor of five (5). Of the 33 additional hangers with struc-tural steel shapes, Attachment I shows that 7 hangers had been included in the original inspection / testing program and were successfully tested.

It is expected that the success rate for the structural shapes shall equal or bet-ter that of the flat baseplates. This evaluation is based upon the following factors.

Structural shapes are inherently more rigid than flat plates and are therefore less susceptible to the prying effect. Further, the Bergen Patterson Pipe Support Com-pany, designer of the supports in the Reactor Building, used a factor of safety of ten (10) on the bolts as compared to the original design criteria. The seismic loads on the supports were determined based on the response of the highest ele-vation of the Reactor Building without respect to the actual locations.

Based on these factors, and the small number of anchor bolts involved compared to the large number we have already tested, we believe the acceptability of the anchor bolt installation has been adequately demonstrated without further test:ng.

1795 006

NRC Action item No. 7 For those IIcensees that have had no extended outages to perform the testing of the inaccessible anchor bolts, the tecting of anchor bolts in accessible areas is expected to be completed by November 15, 1979 The testing of the inaccessible anchor bolts should be completed by the next extended outage.

For those IIcensees that have completed the anchor bolt testing in inacces-sible areas, the testing in accessible areas should continue as rapidly as possible, but no longer than March 1, 1980. The analysis for the Bu11eti, items covering base plate flexibility and factors of safety should be completed by November 15, 1979 Provide a schedule that details the com-pletion dates for IE Bulletin No. 79-02, Revision 2, items 1, 2, and 4.

Response to Action item No. 7 All actions under this item have been completed and were addressed in our sub-mittals of July 6 and August 3, 1979 1795 007'

~

Attachment 1 SHAPE HANGER LINE TYPE OF ATTACH- ACCESSIBLE PULL TEST HARK NO. SIZE ANCHOR BOLT MENT YES/NO YES/NO SYSTEM

~

YES NO 1D' l-1/4" Hilti Angle Containment Spray NQ-2-H 38A YES YES 6" 1/2" P.R. Angle NQ-2-H39 la' 5/8" P.R. B.P. ,

- Core Spray NZ-2-H3 YES NO Partu6H YES NO NZ-2-H4 le' 5/8" P.R. Angle YES YES 11' 5/8" D.R. Angle NZ-2-HS YES YES 6" 5/8" P.R. Angle NZ- 2-H12 VES YES 6" 5/8" P.R. Angle NZ-2-H13 S' 1/2" P.R. B.P. YES N Z H3C YES Part SG High Rad Area NO 6" Not Access. Angle NZ-2-H39 YES NO NZ-2-H42 6" Not Access. Angle Angle High Rad Area NO NZ-2-H44 10" 3/4" P.R.

YES NO Emergency Condenser NE-2-H13A 18" l-1/2" Hil ti Angle YES NO 28" 5/8" P.R. Angle NE-3-H3 Angle YES NO NE-3-H4 20" 5/8" P.R. NO 5/8" P.R. Angle YES NE-3-H5 20" NO 3/4" P.R. Angle YES NE-5-H3 18" NO 1" Hilti Angle YES NE-5-H3A 16" NO 1" Hilti Angle YES NE-5-H3B 16" NO 1" Hilti Angle YES NE-5-H5 16" NO 1" Hilti Angle YES NE-5-H6 16" NO 1/2" P .R. Angle YES CH-5-H3 3" Emergency Service Angle YES NO Water SW-SN-1 i4" 7/8" P.R. NO-Angle. NO SW-SN-2 14" 7/8" P.R. YES 3/4" P.R. Angic YES SW-SN-8 14" NO 7/8" P.R. Angle YES SW-SN-25 14" NO 3/4" P.R. Angle YES SW-SN-35 14" NO 3/4" P.R. Angle YES NW-SN-Al 14" High Rad Area WF SW-SN-44 14" 3/4" P.R. NO NO 3/4" P.R. UF High Rad Area SW-SN-45 14" NO NO WF High Rad Area SW-SN-46 14" 3/4" P.R. NO NO YES Angle YES Poison Pipin9 NP-1-H1 2-1/2" 1/2" P.R.

NP-1-R6A Accumu- NO Angle YES lator 3/8" P.R.

NP-1-R6B Accumu- NO Angle YES lator 3/8" P.R.

l795 008~