ML20003C197
| ML20003C197 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/06/1981 |
| From: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-79-02, IEB-79-2, NUDOCS 8102260845 | |
| Download: ML20003C197 (12) | |
Text
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Consumers Power Company Generet offkes: 212 West M6chigen Avenue, Jackson. Michigen 40201 + (517) 7884650 February 6, 1981
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Mr James G Keppler f
Office of Inspection and Enforcement E
CJ Region III d
2S7NIA 8 US Nuclear Regulatory Commission
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- h..a. %%%r 799 Roosevelt Road Glen Ellyn, IL 60137
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DOCKET 50-155 - LICENSE DPR g BIG ROCK POINT PLANT - FINAL RESPONSE 4
TO IE BULLETIN 79 PIPE SUPPORT BASEPLATE DESIGNS USING CONCRETE EXPANSION ANCHOR BOLTS IE Bulletin 79-02 entitled " Pipe Support Baseplate Designs Using Concrete Expansion Anchor Bolts" (March 8, 1979) and its revisions and supplement requested Consumers Power Company to perform inspection and testing of concrete expansion anchor bolts which provide anchorage for pipe supports in Seismic Category I systems. provt. des Consumers Power Company's final Big Rock Point response to IE Bulletin 79-02 and its revisions and supplement. The enclosure provides a summary of the inspection / test and repair programs and the results achieved.
Detailed calculations and inspection / test data are available for on-site review.
l t-David P Hoffman Nuclear Licensing Administrator CC Director, Office of Nuclear Reactor Regulation Director, Office of Inspection and Enforcement NRC Resident Inspector-Big Rock Point Attachment, 11 Pages oc0281-0075a-43 gg 9 #
81022 60W5 0
ENCLOSURE 1 FINAL RESPONSE TO USNRC IE BULLETIN 79-02 AND ITS REVISIONS FOR CONSUMERS POWER COMPANY BIG ROCK POINT NUCLEAR POWER PLANT CHARLEVOIX, MICHIGAN nu0281-0075a-43
FINAL RESPONSE TO NRC IE BULLETIN 79-02 AND ITS REVISIONS CONTENTS Page No 1.
GENERAL 1
2.
ANCHOR BOLT TESTING AND INSPECTION REQUIREMENTS 2
3.
TEST AND INSPECTION RESULTS 3
4.
CONCLUSIONS 4
nu0281-0075a-43
1 1.
GENERAL A.
INTRODUCTION This is in response to Nuclear Regulatory Commission (NRC) IE Bulle-tin 79-02, Revisions 1 and 2, and Supplement 1.
I addresses all safety-related pipe supports using concrete expansion anchor bolts (CEBs). The bulletin, revisions and supplement are noted as Refer-ences 1-4.
Reference 5 is the 120-day response to those bulletin requirements for the Palisades Plant. Reference 5 contained various inspection and testing guidelines which were general enough to be applicable to any facility. Reference 6 was the 120-day bulletin response for the Big Rock Point Plant which identified the scope of work that is specifically required by the bulletin.
In addition, Reference 6 indicated that the general procedures as identified in Reference 5 with respect to inspection, testing, repair and material procurement would apply to Big Rock Point as well. Reference 7 was a plant specific reply for Big Rock Point which addressed concerns with respect to CEBs in concrete block walls, structural steel use instead of baseplates and inspection / outage considerations.
Reference 8 was an interim report for Palisades which contains test information with respect to torque / tension relationships and shell type CEB shoulder-to-cone effects on ultimate bolt capacities. The data in Reference 8 and Reference 9 were judged applicable to the Big Rock Point testing program and were employed in determining CEB inspection and testing requirements. Reference 10 contains CEB test data and installation guidelines for all types of Phillips Drill Company CEBs.
It has been determined that recent piping modifications use these CEBs.
It has also been assumed with a high degree of confidence that all CEBs at Big Rock Point are from that supplier.
Therefore, Reference 10 was used in the inspection and testing program.
B.
SCOPE A detailed inspection of the Big Rock Point Plant safety-related piping resulted in the identification of four systems containing pipe supports using CEBs. These systems were:
Redundant Core Spray System (PIS)
Reactor Clean-Up System (RCS)
Shutdown Cooling System (SCS)
Reactor Depressurization System (RDS)
These four systems contained 29 baseplates using CEBs. Of these systems, only the Reactor Depressurization System (RDS) had been subject to a rigorous enough piping analysis to be considered adequate to provide pipe support loads suitable for detailed baseplate and
. anchor bolt load evaluation. Calculated loads were employed for the resolution of deficiencies for the RDS only. For the other systems, nu0281-0075a-43
2 O
inspection and testing criteria were based upon the bolt size and baseplate encountered.
Of the 29 baseplates found, only 25 were actually incorporated into the scope of the bulletin.
It was determined that the two baseplates associated with the RCS should be eliminated from the program due to inaccessibility. There existed a general field of - 250 mrem /h and a local hot spot of 1.5 R/h in the general work area. Full face mask respirators would have been required throughout testing. Two other baseplates associated with the RDS were not included in the scope.
The location of the baseplates was very high up on the steam drum enclosure wall and was judged to pose a safety concern. The support itself incorporated a member welded to a pipe segment of a very stiff piping system.
It was also determined that the 1-1/4-inch diameter wedge anchors in these supports were adequately sampled per the other baseplates in the RDS.
2.
ANCHOR BOLT TESTING AND INSPECTION REQUIREMEhrS The basic CEB inspection and testing requirements were essentially the same as those described in Reference 5 except that no statistical sa=pling was done. Directly measurable requirements for the four types of bolts found are reflected in Tables 1 and 2.
The requirements of those tables were augmented by inspections to ensure no cracks in the concrete, no bolt holes exceeding the bolt head across-the-flats width and no thin base-plates existed.
A.
BOLT REQUIREMENTS All shell type anchors were tensile tested to verify that the require-ments of Table 1 were met.
The test tensile loads are those recom-mended in Reference 10 and reflect a margin of four with respect to 3,000 psi concrete. The other requirements of Table 1 for shells were also from Reference 10 with the exception of the shoulder-to-cone (S/C) dimension. The S/C tolerances were based upon results from Reference 9 and were confirmed from test results detailed in Reference 8.
Wedge type anchors were torque tested due to the limitations of tension testing fixtures. The test and inspection requirements of Table 1 for wedge anchors were consistent with Reference 10 with the exception of the test torque.
Table 2 provides information gathered and extrapolated from Refer-ence 8 testing performed at Palisades. The four CEBs of Table 2 are the only types found at Big Rock Point. Other data from Reference 8 for 7/8-inch diameter bolts confirm the acceptability of a.25 K value for unlubricated anchor bolts greater than 1/2-inch diameter.
It is noted that the reinstallation torque values imply an average. tension slightly greater than the test load for shells. The 260-ft-lb torque with an average K value of.25 implies an average tunsile load 15 percent greater than the recommended design value per Reference 10 and 33 percent greater than the load limit imposed in the RDS design nu0281-0075a-43
3 i
document for such bolts.
Both Referance 10 and the RDS design document include a safety factor of four.
B.
BASEPLATE REQUIREMENTS The discussion of Item 5 of the enclosure to Reference 11 applies to Big Rock Point as well, even though the baseplates were not analyzed in detail either because support loads were not known or because the existing (applying to RDS) support baseplate analysis was considered adequate. The results of work reflected in Reference 11, which was the final Palisades response to IE Bulletin 79-02, implies that, if a baseplate met the requirements of Reference 12 as applied to column plate design, the baseplate is stiff enough that prying action is of a negligible effect. The baseplates for which loads were calculated in the design (RDS) were analyzed per AISC procedures. A review of those calculations has indicated that the baseplate thicknesses are adequate to preclude prying action.
3.
TEST AND INSPECTION RESULTS The results of the testing and inspection program are summarized in Tables 3 and 4 for the four types of bolts encountered on the three systems inspected and tested. The program addressed a single bolt per baseplate.
If the bolt failed any of the inspection or tasting requirements of Tables 1 and 2, all bolts associated with the baseplate were inspected and tested for all attributes. Failures of 13 of the 25 bascplates addressed were recorded. Twenty-two additional bolts associated with these 13 baseplates were subject to an extended evaluation due to these failures. None of the additional bolts evaluated failed any inspection or testing criteria. Table 3 summarized the 47 bolts tested with respect to type.
Table 4 provides a failure accountability of the 15 failure attributes for the 13 bolt failures associated with 13 baseplates. The three thr.aad en-gagement failures were all repaired to provide 3/4 inch of engeasaent.
The six shoulder-to-cone failures on the PIS were all repaired to meet the bounds noted in Table 1.
The two protrusion conditions were associated with shoulder-to-cone failures and they were repaired. The violations of minimum bolt center line-to-center line spacing for the snap-off shells did not require repair. The calculated loads imposed on these bolts were low enough to provide a safety margin of five even while accommodating a ratioed down pullout allowable. Therefore, the discrepancy was dispositioned as acceptable. The violations of bolt center line-to-center line spacing for the wedge anchors did not require repair. A review of the calculated bolt loads showed the bolts to be almost entirely in shear.
Thus, the effect of the spacing condition was minimal and the required safety f actor was preserved. For purposes of evaluating the center line-to-center line conditions, a linear shear-tension interaction relationship per Reference 10 was employed, nu0281-0075a-43
4 4.
CONCLUSIONS An inspection and testing program has been conducted in order to meet the intent and requirements of IE Bulletin 79-02 and its revisions. A plan was submitted (Reference 5) which indicated the scope of the bulletin as it applies to Big Rock Point and which also proposed that procedures proposed for Palisades would be used. A special site test procedure was written to implement the program. The procedure sustained only minor revisions which were needed to incorporate new information on shell type anchor shoulder-to-cone tolerances and torque tension interaction relationships. The inspection process involved a "one bolt per baseplate" sampling process. Failures of the sample bolts for bolt characteristics required inspection and testing of the remainder of the baseplate bolts and repair where necessary. All procedures, test results and dispositioning of failures are a matter of permanent record.
nu0281-0075a-43
TABLE 1 ANCHOR TEST / INSPECTION REQUIREMESTS SHELL TYPE ANCHORS Bolt Diameter 1/2" 5/8" 3/4" Tensile Load 1,870 Lb 2,574 Lb 3,564 Lb Thread Engagement 1/2" 5/8" 3/4" Shoulder-to-Cone 1-1/16" 3/16" 1-1/4" 5/8" 1-7/8" 1/16" Shell Protrusion None None None Bolt Center Line-to-Center Line 5"
6" 7"
Edge Distance 1-15/16" 2-3/8" 3"
WEDGE TYPE ANCHORS
___ Anchor Size 1-1/4" Torque (Ft-Lb) 260 Stud Length 12" Nut Engagement Full Thread Nut Bottoming 3-1/4" Stud Projection Embedment Depth 5-1/2" Bolt = Center Line-to-Center Line 8-3/4" Edge Distance 5-1/2" nu0281-0075a-43'
=
- _ - =.. _-
TABLE 2 TESTING AND REINSTALLATION TORQUE / TENSILE LOADS Torque Equiv Tension Test Tension Bolt Size - Type K Ave Ft-Lb Load Lb Load Lb 1/2" Shell
.241 30 2,988 1,870 5/8" Shell
.239 40 3,213 2,574 3/4" Shell
.246 65 4,228 3,564 1-1/4" Wedge
.250*
260**
9,984
- The.25 K value was determined from testing at Palisades as an extrapolation of test data from 1/4" to 7/8" anchors. The other K values in these tables are from Palisades data. The torque load is the product of the K value, bolt diameter and equivalent tension load (Reference 8).
- The 260-ft-1b test torque was used to achiave 10,000-lb equivalent tension which exceeds the 8,700 lb recommended for a 3,000 psi design load per Reference 10 and which comfortably exceeds the 7,530-1b design load employed in the support design of the Reactor Depressurization System, nub 281-0075a-43
TABLE 3
SUMMARY
OF TEST RESULTS Hanger Plates Available for Testing / Tested Redundant Core Spray System (PIS) 9/9 Shutdown Cooling System (SCS) 4/4 Reactor Depressurization System (RDS) 14/12 Reactor Clean-Up System (RCS) 2/0 Total 29/25 Bolt Sampling Results Sampled Bolts 25 Passed Bolts 12 Failed Bolts 13 Repaired Bolts 9
Extended Evaluation Additional Bolts Tested 22 Failed Bolts 0
Retests of Sample 9
Bolt Types Addressed - Sampled Plus Extended Testing Type Number Tested 1 i/4" Wedge 10 5/8" Shell 2
3/4" Shell 13 1/2" Shell 22 nu0281-0075a-43
T..BLE 4 BOLT FAILURE ACCOUNTABILITY Type Failure System No Failures Anchor Type FOR SHELLS Thread Engagement SCS 3
3/4" Shells Tension / Torque Shoulder-to-Cone PIS 6
1/2" Shells Protrusion PIS 2
1/2" Shells Bolt Center Line-to-Csater Line RDS 2
5/8" Snap-Off Shells Edge Distance FOR WEDGES Nut Engagement Nut Bottoming Embedment Depth Tension / Torque Bolt Center Line-to-Center Line RDS 2
1-1/4" Wedges Edge Distance l
l nu0281-0075a-43 i
f REFERENCES 1.
IE Bulletin 79-02 dated March 8, 1979.
2.
IE Bulletin 79-02, Revision 1, dated June 21, 1979.
3.
IE Bulletin 79-02, Revision 1 Supplement 1, dcted August 20, 1979.
4.
IE Bulletin 79-02, Revision 2, dated November 8, 1979.
5.
CP Co letter to NRC (Palisades) dated July 6, 1979.
6.
CP Co letter to NRC (Big Rock Point) dated July 6, 1979.
7.
CP Co letter to NRC (Big Rock Point) dated December 13, 1979.
8.
CP Co letter to NRC (Palisades) dated February 14, 1979.
9.
Burdette, E G, Tests on Self-Drilling Anchors, Department of Civil Engineering, University of Tennessee, July 1979.
10.
Red Head Anchor Systems, Catalog F-1000, Phillips Drill Division of ITT, 1976.
11.
CP Co letter to NRC (Palisades) dated August 15, 1980, 12.
AISC,1970, Manual of Steel Construction, American Institute of Steel Construction, 7th Edition, New York, nuo281-0075a-43 s,