IR 05000315/1986023
| ML17326B247 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/04/1986 |
| From: | Danielson D, Norton J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML17326B246 | List: |
| References | |
| 50-315-86-23, 50-316-86-23, IEB-79-02, IEB-79-2, NUDOCS 8606100316 | |
| Download: ML17326B247 (5) | |
Text
U.S.
NUCLEAR REGULATORY COMMISSION
REGION III
Reports No. 50-315/86023(DRS);
50-316/86023(DRS)
Dockets No. 50-315; 50-316 Licenses No.
American Electric Power Service Corporation Indiana and Michigan Power Company 1 River side Plaza Columbus, OH 43216 Facility Name:
D.
C.
Cook Nuclear Plant, Units 1 and
Inspection At:
D.
C.
Cook Site, Bridgman, MI Inspection Conducted:
May 21, 1986 Inspector:
J.
F. Norton p.~.a-6 l.4
Date Approved By:
D.
H.
D nielson, Chief Materials and Processes Section Date Ins ection Summar Ins ection on Ma
1986 Re orts No. 50-315/86023 DRS 50-316/86023 DRS Areas Ins ected:
Unannounced, routine inspection of licensee action on IE Bulletin No
~ 79-02 "Pipe Support Baseplate Design Using Concrete Expansion Anchor Bolts."
Results:
No violations or deviations were identified.
8bOb 1 003 l b 8bOb00 J'DR ADOCK, 05000315
'
DETAILS 1.
Persons Contacted Indiana and Michi an Electric Com an I8MEC
- M. G. Smith, Jr., Plant Manager
~A. A. Blind, Assistant Plant Manager
- G. H. Caple, Administrative Compliance Coordinator D. L. Gallagher, Administrative Compliance Coordinator, guality Control American Electric Power Service Cor oration AEPSC
~T.
R. Satyan-Sharma, Senior Engineer, Safety and Licensing
- J.
E. Petrucelli, Assistant Section Manager, Structural Design
"F. A. Accetta, Staff Engineer, Civil Engineering
- R. T. Huerter, Senior guality Assurance Auditor US Nuclear Re ulator Commission B.
L. Jorgensen, Senior Resident Inspector
"J.
K. Heller, Resident Inspector
- Denotes those attending the exit interview.
2.
Licensee Action on IE Bulletins (Closed)
IE Bulletin No. 79-02 (315/79-02-BB; 1B; 316/79-02-BB; 1B):
IE Bulletin No. 79-02 "Pipe Support Baseplate Design/Construction Using Concrete Expansion Anchor Bolts."
A review of relevant information revealed that IE Bulletin No. 79-02 requirements have fully been implemented at D.
C.
Cook Units 1 and 2.
~Back round IE Bulletin No. 79-02 addresses pipe support baseplate design using concrete expansion anchors.
Teledyne Engineering Services (TES) was authorized by fourteen utilities (including 18MEC) to provide engineer-ing services which would assist the utilities in responding, in part, to IE Bulletin No. 79-02, dated March 8, 1979.
IE Bulletin No. 79-02 required response to a number of items associated with baseplate flexibility and its concomitant effect on concrete expansion anchor bolts.
It was determined by the Utility/TES group that a number of items in the bulletin were generic in nature and could be addressed more substantially by combining resources and technology.
The specific bulletin items addressed by the Utility/TES group were:
The experimental development of shear-tension interaction curves to properly apply the bulletin safety factors for combined loading.
Experimental determination of the adequacy of concrete anchor bolts that are not preloaded to withstand cyclic loading.
An analytical technique for determining the effect of baseplate flexibility on concrete anchor bolt 'loading.
The Owner's Group was responsible for directing the efforts of TES and reviewing the specific tasks as they were performed and completed.
On April 26, 1979, the Utility/TES group met.with the NRC in Bethesda, Maryland to discuss this generic program and its applicability to IE Bulletin No. 79-02.
Representatives from I&E and NRR were in attendance and their general conclusion was that "the proposed program would address the concerns for the base plate/anchor bolt installation in a fashion that is acceptable to NRC."
TES submitted Technical Report TR-3501-1, Revision 1, dated August 30, 1979.
The report presented the results of a generic program that responded, in part, to the Bulletin.
Both experimental and analytical work was performed in this generic program.
Shear-tension interaction tests and cyclic test of concrete expansion anchors were performed and a pre and post processor to an existing finite element program was developed to facilitate baseplate analysis.
The important general findings of this program are:
Concrete expansion anchor bolts which are preloaded do not deteriorate when subjected to cyclic loading.
A linear assumption for shear-tension interaction loading on concrete expansion anchors is highly conservative.
Baseplate flexibility should be considered in determining the load on concrete expansion anchors.
Testing performed under the program does not indicate a reason for applying different safety factors to different types of expansion anchors.
Subsequently, the NRC staff performed an independent analytical verification of the techniques used to account for baseplate flexibility and its effect on anchor bold loads.
The independent analytical verification consisted of developing an elastic beam-based model of an anchored plate, subjected to static combined axial and moment loading.
The concrete base was represented by elastic springs which were capable of sustaining compression only.
The anchoring bolts were represented by springs which reproduced the non-linear behavior of the bolts during pull-out.
The model also accounted for initial preload in the bolt-plate assembly.
The solution to a given
loading condition (i.e., bolt load vs. external load history) was obtained through an in-house developed computer program, which calculated the non-linear behavior in an incremental approach, including equilibrium interaction.
Based on the review and independent verification, the NRC staff concluded that the techniques applied by TES correctly accounted for pipe support baseplate flexibility and was therefore acceptable.
Licensee Action In addition to the generic data developed by TES, the licensee further retained their services to provide a plant specific evaluation of seismic Category I pipe support baseplates and expansion anchors.
The engineering analysis is documented in Technical Report TR-3611-2, dated June 27, 1980.
Supports were first screened using a conserva-tive procedure to determine anchor bolt forces.
Allowable forces were reduced to a low level to account for plate flexibility and prying action as well as shear-tension interaction.
Those supports not passing this first level of screening were subjected to a second level of screening which was more precise and less conservative.
Supports not passing second level criteria were either analyzed by rigorous computer techniques or the designs were modified to achieve acceptable bolt forces.
All rigorous analyses and modifications were checked and verified in accordance with TES Quality Assurance requirements.
Pipe support baseplate modifications were required on 64 supports for Unit 1, and 95 supports for Unit 2.
The majority of modifications were designed by TES and used one or more of the following methods:
Stiffening of the existing baseplate.
Anchor bolts added to exi sting basepl ates.
Additional strutting plus baseplate and anchor bolts were added to the existing frame.
Conclusion Baseplate modification have been completed.
The modification were accomplished in accordance with licensee engineering and QA/QC requirements.
The Region III inspector reviewed paper work and examined several of the modified plates.
No discrepancies between design drawings and construction were discerned.
Based on the aforementioned data, it is concluded that IE Bulletin No. 79-02 has been fully implemented at D.
C.
Cook Units 1 and Ei
% iq The inspector met with licensee representatives (denoted under Persons Contacted)
on Nay 21, 1986.
The inspector summarized the purpose and findings of the inspection.
The licensee acknowledged the findings as reported herein.
The inspector also discussed the likely informational content of the inspector's report with regard to documents or processes reviewed by the inspector during the inspection.
The licensee did not identify any such documents/processes as proprietary.