ML20062G845

Forwards Supplemental Info Supporting Util Overall Plan to Address Drywell Corrosion Issue at Facility

ML20062G845
Person / Time
Site:	Oyster Creek
Issue date:	11/26/1990
From:	Devine J GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20062G848	List: ML20062G845 ML20062G849 ML20062G852 ML20062G855 ML20062G860 ML20062G864
References
C320-90-264, NUDOCS 9012030047
Download: ML20062G845 (5)

Text

n retion M J;  ; a ge OPU Nuclest One Upper Corpoad Pond I Hair 4 -

GB Partippany, New Jessy 07054 201 316 7000 N0vember 26, 1990 TELEX 136-482 5000-90-1993 wrner's Direct Dial Number:

C320-90-264 U. S. Nuclear Regulatory Commission Attention: Document Control Desk (

Washington, DC 20555 Gentlemen Subject Oyster Creek Nuclear Generating Station (OCNGS)

Docket No. 50-219 License No. DPR-16 Oyster Creek Drywell Containment

References:

(1) HRC letter dated October 3, 1990 - Summary of September 19, 1990 meeting (2) HRC letter dated October 16, 1990 - Requested Clarifications On Wednesday, September 19, 1990, a meeting was held with the NRC at the NRC offices, One White Flint North, Rockville, Maryland. The purpose of this meeting was to discuss GPUN's overall plan to address the drywell corrosion issue at the Oyster Creek Nuclear Generating Station. The Reference (1) letter documents the participants, morning and afternoon presentations and summarizes the significant items discussed.

The NRC requested detailed supplemental information supporting GPUN's anscomment be submitted no later than December 31, 1990.

The requested information specified by Reference (2) consists of the following four (4) items (1) Drywell Inspection Plan Details (original and augmented) which includes justification of Sampling Techniques and Statistical Methodology.

(2) Point-By-Point Code Comparison justifying ASME Section III, NE Methodology for the ASME Section VIII Drywell/ Containment Vessel.

(3) Structural Design Report justifying operation to 14R refueling outage based on ASME Section III, NE Methodology using 62 psig as drywell design pressure.

(4) GPUN Actions to prevent leakage into the drywell gap and the effects of leakage on other structures or equipment.

9012030047 901126 POR ADOCK 05000219 p PDC

~ . . . . , p GPU Nuclear Corporation is a subsidiary of General Pubhc UtMtes Corporation /

,,,,J,.-,, - , , , , , , , , , , , - .

Oyotor Crook Dryw311 Containmant C320-90-264 Page 3 In order to expedite NRC review of the requested information, individual submittals will be provided as the documentation of each item is finalized.

Attachment I to this letter provides the information requested by the NRC for Item (1) and includes a brief summary of the overall drywell inspection plan and the following technical dccumentation.

• GPUN TDR 948, Rev. 1, " Statistical Analysis of Drywell Thickness Data."

' GPUN Specification 28-328227-004, Rev. 8, " Functional Requirements for Drywell containment Vesuel Thickness Examination."

• GPUN Calculation C-1301-187-5300-011, Rev. O, " Statistical Analyeis of Drywell Thickness Data from 4/24/90" (Appendices 6.1 to 6.3 not attached).

• GPUN TDR 1027, Rev. 1, " Design of a UT Inspection Plan for the Drywell containment Using Statistical Inference Methods."

• GPUN Specification IS-402950-001, Rev. O, " Functional Requirement for Augmented Drywell Inspection."

It is CPUN's goal to provide submittal items (2) through (4) as they become available but no later than December 31, 1990. GPUN will, of course, inform the NRC of any changes to the corrosion assessment which would compromise our technical justification for continued operation of the OCNGS.

If you have any questions on this submittal or the overall drywell corrosion program, please contact Mr. Michael Laggart, Manager, Corporate Nuclear Licensing at (201) 316-7968.

Sincerely

• I fi&g - h I

l

- A LxA e -e J. C. DeVine, Jr.

- Vice President, Technical Functions JCD/RZ/ pip m Attachment

, cc's on next page 2

RZ C320264

Cy0 tor CrO k Drywell Contcinment C320-90-264 Page 3 cci Administrator Region 1 U.S. Nuclear Regulatory Commission 475 A11endalo Road King of Prussia, PA 19406 NRC Resident Inspector oyster Creek Nuclear Generating Station Forked River, NJ 08731 Project Manager U.S. Nuclear Regulatory Commission Mail Station F1-137 Washington, DC 20555 l

l i

l l

l l

l RZ:C320264

ATTACHMENT I

SUMMARY

OF GPUN OVERALL DRYWELL INSPECTION PLAN The CPUN drywell inspection plan is separated in two portions. The first portion is an inspection program intended to determine corrosion rates which are utilized to develop conservative projections.

In this portion of the program, UT inspections are performed over time at the same specific locations. The inspections are performed during outages of opportunity when a drywell entry is made for reasons other than program inspections. 20 priority #1 locations are inspected not more frequently than 3 months, and 7 priority #2 locations are inspected not more frequently than 18 months. These inspection locations were identified during detailed inspection of elevations 11'-3", 50'-2", 51'-10" and 87-5" conducted in 1986, 1987 and 1990. During the 13R outage, CPUN will perform inspection of all priority #1 locations, once at the beginning of the outage and once at the end of the outage. Included in this attachment are copies of the GPUN internal reports which provide details of data collection and data reduction, as well as the most recent results for inspection up to April 1990. Also provided is Specification IS-328227-004, Rev.

8 which presents functional requirements for inspection implementation.

The second portion of the program will be implemented for the first time during the 13R outage and is intended to statistically confirm required drywell thicknesses. This portion of the program relies on UT inspection of 57, 6x 6 inch randomly chosen locations. The resulting inspection data will characterise the condition of the upper elevations of the drywell.

As part of this Attachmer.t are copies of a CPUN Report which provides details of how the amount and the location of the 57 inspection locations were determined and Jpocification 23-402950-001 which presents functional requirements for this augmented inspection implementation in 13R.

PT/ Dry

-- m. m__-. -n:__:-s_m.___.____mm. s_____.-___.__ ._____.____ -- . . _ __m._-__._-_-____._m-._-_.- _ m-. _ _..-____.__._____u

ATTACHMENT I (CONTINUED) l TECHNICAL DOCUMENTATION

• CPUN TDR 948, Rev. 1, "Stasistical Analysis of Drywell Thickness Data." i 1

• OPUN Specification IS-328227-004, Rev. 8, " Functional Requirements for Drywell containment Vessel Thickness Examination." l

' GPUN Calculation C-1302-187-5300-Oll, Rev. O, " Statistical Analysis of Drywell Thickness Data from 4/24/90" (Appendices 6.1 to 6.3 not attached).

• GPUN TDR 1027, Rev. 1, " Design of a UT Inspection Plan for the Drywell Containment Using Statistical Inference Methods."

• CPUN Specification IS-402950-001, Rev. O, " Functional Requirement for Augmented Drywell Inspection."

PT/ Dry

_ _ __ _ _ _ _ . _ _ . _ . . _ . _ ._. - _ . . . _ _ _ _ _ _ _ _ _ _ _