ML20205D389

Insp Rept 50-424/86-42 on 860505-07.No Violations or Deviations Noted.Major Areas Inspected:Independent Design Review for Readiness Review Module 13C,Chapter 7

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: ML20205D379 ML20205D389
References
50-424-86-42, NUDOCS 8608150347
Download: ML20205D389 (3)

See also: IR 05000424/1986042

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ENCLOSURE

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i U.S. NUCLEAR REGULATORY COMMISSION

l 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: ,

Hai-BToh Wa~ng

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T am Leader

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Approved By: jg E.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,

j 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

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. l

The NRC team agrees with the finding, but considers the project response l

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 /

method using FINEL accounts for the thermal effects at the discontinuity. ('

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

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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