IR 05000500/1979002
| ML19296C973 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 01/22/1980 |
| From: | Clint Jones, Williams C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML19296C969 | List: |
| References | |
| 50-500-79-02, 50-500-79-2, 50-501-79-02, 50-501-79-2, NUDOCS 8002290156 | |
| Download: ML19296C973 (6) | |
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U. S. NUCLEAR REGULATORY COMMISSION
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OFFICE OF INSPECTION AND ENFORCEMENT
REGION III
Report No. 50-500/79-02; 50-501/79-02 Docket No. 50-500; 50-501 License No. Pre-CP Licensee: Toledo Edison Company Edison Plaza 300 Madison Avenue Toledo, Ohio 43652 Facility Name:
Davis-Besse Nuclear Power Station, Units 2 and 3 Inspection At:
Davis-Besse Site, Oak Harbor, Ohio Inspection Conducted: December 17-18, 1979 L>
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Inspector: C. E. ',Jone s
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Approved by:
C. C. Williams, Chief
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Projects Section 2 Inspection Summary Inspection on December 17-18, 1979 (Reports No. 50-500/79-02; 50-501/19-02)
Areas Inspected: Discussed the project status and reviewed the records of work perf ormed pursuant to the LWA as amended Septe:cber 13, 1978, authorizing drilling and remedial grouting of Category 1 areas of the plant.
Observed the area that had been grouted, overburden not removed. This inspection involved a total of nine inspector-hours onsite by one NRC inspector.
Results: No deviations form commitments were identified during the inspection.
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DETAILS
Persons Cottacted Principal Licensee Employees
- G. W. Eichenauer, Field QA Supervisor
- A. Schumake r, Assistant Field QA Supervisor Woodward - Cly_de Consultants K. A. Anderson, Project Manager
- Denotes these personnel attending exit interview.
Functional or Program Areas Inspected Details of functional and program areas inspected are as follows.
1.
Organizational Announcements The inspector was informed of the organizational announcements made by Mr. John P. Williamson, Chairman and Chief Executive Officer, on November 27, 1979. The following actions were to be effective December 1, 1979.
Mr. Richard P. Crouse, Vice President-Energy Supply, was redesignated a.
as Vice President Nuclear and was elected to the company's Board of Directors.
b.
Mr. Lowell E. Roe, Vice President - Facilities Development, was redesignated as Vice President - Energy Supply and continues as a Company Director.
c.
Mr. Frank W. Kieth, Vice President - Personnel was redesignated as Vice President - Administration.
2.
Bedrock Rock Verification Backgropnd, Limited Work Authorization as Amended a.
Authori::ation to conduct specific additional work was requested in the opplicants letters dated May 25, 1978, and June 6, 1978. The specific work defined was to perform a bedrock rock verification program including exploratory drilling and remedial grouting in the containment, auxiliary building, and turbine building areas of Units 2 and 3-This work was authorized by letter dated September 13, 197E, alter a public hearing was conducted on July 25, 1978 by the Atornic Safety Board and Licensing (Board) on issues covered bf 10 CFF Se: tion 50.10 (e) (3). The Board issued its Supplemental Partir.1 Initial Decision on August 30, 1978. The activities-2-
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authorized by this letter were in addition to those authorized
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by the LWA-1 dated December 31, 1975.
b.
Overview, Drilling, and Remedial Grouting The containment, auxiliary, 2nd turbine building foundations were mapped and nine foundation areas were identified and marked.
During the period October 1978 to April 1979, the remedial treat-ment program was in progress in the nine foundation areas.
Various investigations since 1974 have shown solution activity above elevation 540 feet.
Conclusions from these investigations culminated in the statement in the Preliminary Safety Analysis Report concluding that water-cement grout would be injected into specific zones of bedrock beneath selected foundation areas.
Speci-fications were written to implement the program. Also Woodward-Clyde Consultants developed Quality Control Procedures to monitor the con-struction activities.
Program and Result _3 c.
Basically the program was to fill drill holes that were left from previous explorations, instrument the area with extensometers, drill grout holes and inject grout from elevation 535' to 560',
top of rock formation. Since the overburden was not removed, the existing drill holes were hard to locate.
Filling these was delayed pending resumption of construction and the overburden is removed. The holes will then be redrilled, backflushed, and grouted.
The extensomers were installed with at least one in each grout area.
The extensomers provided the ability to measure any movement of the rock during grouting.
Perimeter holes were normally drilled first and were then followed by the interior holes. The drilled hole was flushed and then pressure tested with water to determine the initial grouting mix.
Grouting was divided into two zones.
These were zone I from 535 to 545 feet elevation and zone 2 from 545 to 560 ft. elevation. The grouting was evaluated after the primary holes were grouted. This evaluation was made by considering the amount of grout injected, number and extent of fast drill zones, and sequence of grouting.
The Project Manager for the Consultants stated that from results of over 1400 holes in Unit 2 and 3, the geologic model has been confirmed; solution activity was present above elevation 540 feet and that results indicate the technical adequacy of injecting grout to sufficiently fill voids so that building loads can be safely supported.
Evaluation of results of the remedial treatment program indicates that the majority of the solution cavities in the upper 20 feet of bedrock have been filled with cement 1 rout and a competent bedrock foundation support has been provided beneath the turbine building-3-
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and upper levels of the Auxiliary Building.
Local rock excavation
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and concrete backfill to foundatior. grade is proposed for the north-east corner of the Auxiliary Building (Q Area No. 1) where an exist-ing exploratory test excavat'on is located.
Remeoial grouting of Unit 2 is reported as complete. Recommendations are presented by the Consultants for the implementation of the Bed-rock Verification Program in Unit 2 foundation when construction is resumed.
d.
Grouting, Unit 3 Grouting for Unit 3 is reported to be 80% complete.
Ten of 46 previously drilled holes were located and filled. The other 35 holes will be grouted when construction resumes and overburden is removed.
Extensometers indicated significant rock movement (0.1 inch to 0.2 inch) in North portion of the turbine building.
Grouting pressure was reduced and the significant movement ceased.
e.
Drill / Grout Unit 2 The status of drilling and remedial grouting for Unit 2 is summarized as follows.
(1) Category 1, upper levels of Auxiliary Building (Q1, Q2, Q3).
Most significant rock movement (.2 inch) was noted in North-West corner of Q1.
Grout pressures were lowere and signifi-cant movement ceased.
(2) Non Category 1, Water treatment building and turbine building grouting was completed.
(3) All holes drilled have been grouted.
(4) Water treatment building, perimteter completed, 47 holes.
Interior started 17 plus 31 more planned.
(5) Turbine Building: All primary, perimeter holes complete (drilled and grouted) (185).
All primary, interior holes complete (254).
65 interior secondaries assigned; 27 complete.
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(Q-1) All primary perimeter holes completed (106); All primary interior holes completed (154).
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(Q-2) 16 of 26 primary perimeter holes completed; O of 19 primary interior holes completed.
(8)
(Q-3) 20 of 22 primary perimeter holes completed; O of 14 primary interior completed.
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The licensee's represenatative states the remedial grouting
program is 80% completed.
Some problems have been encountered.
These are blockage of the lower zone, grout communication to adjacent holes, flow of grout to ground surface (no refusal).
These problems indicate additional grout holes may be required to provide a satisfactory foundation.
Recommendations are y;esented for the implementation of the Bedrock Verification Program in Unit 2 when Unit 2 construction is resumed.
f.
Conclusion The licensee's consultants have prepared two documents concerning remedial grouting of Davis-Besse Units 2 and 3.
The titles are as follows:
1.
Technical Report 12, Remedial Treatment Program - Unit 2 for Davis-Besse Nuclear Power Station Units 2 and 3 By: Woodward-Clyde Consultants, August 22, 1979.
2.
Technical Report 13, Results and Status of Structural Grouting -
Unit 3 for Davis-Besse Nuclear Power Station Units 2 and 3 By:
Woodward-Clyde Consultants, August 18, 1979.
The conclusion of the consultants states that the model is confirmed and the majority of cavities in the upper 20 ft. of bedrock are filled with grout and therefore competent to safely support building loads.
In addition, they state that drill holes must be filled when work is resumed and additional borings, geophysics mapping and seismic reflections done because of top and excavation conditions.
3.
Document Retention A procedure, Structural Grouting - Transfer of Final Documentation Turnover Packages, has been prepared by Woodward-Clyde Consultants and approved by TECo for controlling the turnover of documents. TECo has developed procedures for safe storage of these documents pending resumption of construction.
4.
Project Status Instructions have been issued by Toledo Edison Company to demobilize all contractors associated with the Davis-Besse Units 2 and 3 con-struction project.
Demobilization is to be achievea in an orderly manner to allow ease of remobilization.
Some typical examples of the directed actions are as follows:
a.
Suspend all engineering and procurement activity applicable to plant design.
b.
Settle all claims associated with cancellation or long term suspension of all open purenase orders and contracts.
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c.
Transfer site facilities to Unit No. I jurisdiction as appropriate.
d.
Develop and institute a plan for the receipt, filing, and storage of all records turned over by site contractors and suppliers.
liotify U.S. Nuclear Regulatory Commission and Atomic Safety and c.
Licensing Board of project status and direction.
f.
Suspend the development of the Unit 2 and 3 Project Management System.
g.
Suspend NRC licensing activity.
h.
Monitor status and condition of material and equipment which is placed in storage.
Exit Interview The inspector met with the site representatives (denoted under Persons Contacted) at the conclusion of the inspection. The inspector summarized the purpose and findings of the inspection.
The licensee acknolegded the findings reported herein.
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