ML20205D389
| ML20205D389 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 06/20/1986 |
| From: | Imbro E, Wang H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| Shared Package | |
| ML20205D385 | List: |
| References | |
| 50-424-86-42, NUDOCS 8608150347 | |
| Download: ML20205D389 (3) | |
See also: IR 05000424/1986042
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ENCLOSURE
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U.S. NUCLEAR REGULATORY COMMISSION
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OFFICE OF INSPECTION AND ENFORCEMENT
Division of Quality Assurance, Vendor, and Technical Training Center Programs
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Report No.:
50-424/86-42
Docket No.:
50-424
Licensee:
Georgia Power Company
Facility Name:
Plant Vogtle, Unit 1
Inspection At:
Vogtle Job Site
Waynesboro, Georgia
Inspection Dates:
May 5-7, 1986
Inspection Team:
Team Leader:
H.B. Wang, Inspection Specialist, IE
Civil / Structural:
G. Harstead, Consultant, Harstead Engineering
- E.V. Imbro, Section Chief, Quality Assurance Branch, IE
Prepared By:
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Hai-BToh Wa~ng
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T am Leader
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Approved By:
jgE.V. Imbro
Date
Section Chief
Quality Assurance Branch
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- Attended exit meeting only
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PLANT V0GTLE, UNIT 1
READINESS REVIEW MODULE 13C-CHAPTER 7.0
INDEPENDENT DESIGN REVIEW (IDR)
INSPECTION OF IDR RESULTS AND CORRECTIVE ACTIONS
1.
Background
At a meeting with the NRC in Bethesda, Maryland on June 20, 1985, the Georgia
Power Company (GPC) presented a plan as part of their Readiness Review program
for an Independent Design Review (IDR) of Plant Vogtle Unit 1 (Vogtle) to be
performed by Stone and Webster Engineering Corporation (SWEC). The IDR for all
non-civil / structural design aspects would be presented in a single review docu-
ment or module. The IDR associated with the civil / structural design would be
in modules #1, #8, #13A, #13B, and #13C. The NRC Office of Inspection and
Enforcement activities related to the Vogtle IDR for civil / structural modules
may include, in addition to a review of Chapter 7 of the module, an inspection
to determine the thoroughness of the IDR contractor's review, review of findings
and review of GPC's corrective actions.
2. Purpose
The purpose of this inspection was to review Chapter 7.0 of Readiness Review
Module #13C " Post Tensioning Containment".
Specifically, SWEC's depth of review
was evaluated by selecting certain calculations and independently reviewing them.
A review of the IDR findings and associated GPC corrective actions was performed
to verify their validity and implementation.
3.
Personnel Contacted
The following is a list of personnel contacted during the inspection.
Name
Organization and Position
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W.C. Ramsey
GPC, Readiness Review Manager.
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J.W. Curtin
SWEC, IDR Module 13C Team Leader.
R.W. McManus
GPC, Readiness Review Civil Discipline
Leader,
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G. Creighton
GPC, Civil Readiness Review Team Member.
4.
General Conclusions
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The IDR on Module 13C was performed competently and effectively. The review
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of Specification X2CJ2.10.4 was particularly well done.
There were four
findings on this specification relating to inconsistencies with calculations
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and/or FSAR commitments; however, all of them were editorial in nature having
no technical significance. GPC had submitted an amendment to the FSAR to
correct these inconsistencies.
The NRC team reviewed the corrective actions
and found that they satisfactorily resolved the findings, and considers these
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four findings to be closed.
Other findings concerning the calculations are
identified as Comments 1 and 2, under specific comments.
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5.
Specific Comments
Comment 1
Finding 1 of the SWEC IDR team was that the stiffening effect of the but-
tress was not considered in the containment analysis. The project response
only addressed the membrane portion of the containment cylindrical shell.
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The NRC team agrees with the finding, but considers the project response
should be extended to include the non-membrane portion where the moment and
shear are affected significantly by the buttress due to the discontinuity
at the wall-mat interface. Civil Engineering Study No. 91, covering the
membrane portion, and all additional calculations should be incorporated
into the Vogtle calculation record (0 pen Item 86-42-01).
Comment 2
IDR Findings (2) and (7) pertain to Calculation X2CJ2.9.0 and deal with
thermal load on the containment wall and containment liner, respectively.
The analysis of the containment shell was performed using the computer pro-
gram BSAP for the required load combinations, except that the thermal
effects were not included.
In determining reinforcing bar stresses on
each section, the computer program OPTCON was used with the thermal effects
in the membrane section introduced as a thermal gradient through the thick-
ness of the containment wall.
As the IDR report on Findings (2) and (7) pointed out, this procedure is
valid for membrane zones but cannot account for the thermal effects near
discontinuities. The IDR reviewer was given Civil Engineering Study No. 90,
which was performed by Bechtel for a plant similar to Vogtle. This study
addressed the question of thermal effects at the discontinuity at the wall
may interface by comparing results from computer programs BSAP and OPTCON
with the results of an analysis using the computer program FINEL. The
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method using FINEL accounts for the thermal effects at the discontinuity.
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The FINEL results indicated the percentage changes in rebar stresses due
to thermal effects in both membrane and discontinuity regions. Due to the
similarity of Vogtle to the subject plant of Civil Engineering Study No. 90,
the IDR reviewer was able to extrapolate the results, using the percentage
differences of Civil Engineering Study No. 90, to confirm that the rebar
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stresses at the discontinuity of the Vogtle containment wall-mat interface
were within allowables.
The conclusion reached by the IDR reviewer is acceptable. Calculation
X2CJ2.9.0 should be revised to clearly indicate that the rebar stresses are
within allowables based on data from Civil Engineering Study No. 90. The
methodology used to justify that rebar stresses are within allowables should
be documented with all data from various sources clearly referenced (0 pen
Item 86-42-02).
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