ML20247C232

Provides Util Interpretation for Leaving Leak Chases Plugged During Integrated Leak Rate Test,Per 10CFR50,App J & Requests Exemption to Permit Plugging Leak Chases. Containment Liner Would Serve as Redundant Boundary

ML20247C232
Person / Time
Site:	Callaway
Issue date:	03/20/1989
From:	Schnell D UNION ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ULNRC-1945, NUDOCS 8903300147
Download: ML20247C232 (5)

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2March 20, 1989 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station F1-137 Washington D.C., 20555 ULNRC-1945' Gentlemen:

DOCKET NO. 50-483 CALLAWAY PLANT INTERPRETATION TO LEAVE LEAK CHASES PLUGGED DURING AN INTEGRATED LEAK RATE TEST (ILRT)

References:

1) ULNRC-1542, dated July 10, 1987.

2) T.W. Alexion letter to D.F. Schnell dated March 30, 1988.

Reference 1 requested the NRR Staff to review the interpretation that the combined liner-butt weld along with-the ar.sociated pre-tested channel fillet welds and-leak test connections constitute the actual containment boundary in post accident conditions. This-interpretation would form the basis for not venting the-containment liner weld channels during a containment integrated leak rate test (ILRT).

The staff's position on this matter',.as. discussed in Reference 2, is that the containment liner' weld channels should be vented to the containment atmosphere during the containment ILRT unless 1) the licensee can' demonstrate that the channels would maintain their integrity when subjected to the loading conditions of a postulated design basis accident as well as during normal operation and 2) the design for the "new" pressure boundary of the containment would compare favorably with the ASME Code,Section III, Division I, Subsection NE for Class MC l Components (e.g., item by item comparison with what was done in the design and construction).

With regards to the above staff position, the following information is presented to support an exemption request from 10 CFR 50, App, J to allow leaving the leak chases plugged during a Type A ILRT test.

8903300147 890320 p DR ADOCK 05000483 I \

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m An analysis was performed which compares the design of the Callaway leak chases to the requirements of ASME Code Section III, Division 1, Subsection NE for Class MC Components. This analysis concludes that the Callaway containment liner leak chase system meets the design l

requirements of ASME Subsection III for all pressure i boundary loading applications. l The material for the leak chase channel (A36, A53, A106 l steel) was purchased under the requirements for

" attachment to a safety related pressure boundary". This material is acceptable by the code (as the SA )

equivalents) for the use of pressure boundary '

construction. The installation was made as an attachment to a pressure boundary and was tested for leak tight integrity. However, the material and installation do not j necessarily meet the requirements for a safety related i pressure boundary because the code-required CMTRs for I pressure boundary material are not available for these l channels and the pressure boundary welds lack the f required documentation (i.e.,. weld procedures, welder certifications, etc.). i l

Each leak chase system has a test connection that was j used to perform a halogen leak test in accordance with j Section V of the code prior to the finishing of the '

containment. This test was sufficient to verify that the channels were properly installed and leak tight. Once j l

the pressure tests were completed, the finishing of the containment resulted in many of these test connections becoming inaccessible.

The containment liner of the Callaway Plant is designed such that the majority of pressure boundary welds are exposed to the containment atmosphere. No welds in the dome are covered with leak chases, less than 2% of the welds on the containment shell are covered with leak chase channel, but almost all welds on the containment floor are covered. The containment floor is finished with 18 inches of concrete which will protect these leak chases from the affects of accident loading. In addition, most of the inaccessible test connections are located in high radiation areas and would incur a significant amount of radiation exposure to uncover.

ANSI N45.4 recognizes that some portions of the containment boundary will be inaccessible after construction and allows for the performance of special testing before the component becomes inaccessible. At Callaway, halogen leak testing was performed prior to the completion of containment.

.- l An exemption to 10 CFR 50 Appendix J is requested to allow leaving the leak chases plugged during a Type A ILRT. The leak chase material meets the design .

requirements for all pressure loading applications, and 1 if the leak chase system were to fail, then the l containment. liner would serve as a redundant boundary.

Very truly yours,

/

Donald F. Schnell DFS/ dis l

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cc: Gerald Charnoff, Esq.

Shaw, Pittman, Potts & Trowbridge

., 2300 N. Street, N.W.

Washing ton, D.C. 20037 Dr. J. O. Cormah CFA, Inc.

4 Professional Drive (Suite 110)

Gaithersburg, MD 20879 R. C. Knop Chief, Reactor Project Branch 1 U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Little Callaway Resident Office I

U.S. Nuclear Regulatory Commission RR#1 Steedman, Missouri 65077 Tom Alexion (2)

Office of Nuclear Reactor Regulation U.S. Nuclear Regult. tory Commission 1 White Flint, Norch, Mail Stop 13E21 11555 Rockville P'ke Rockville, MD 20852 Manager , Electric Department Miscouri Public Service Commission P.O. Box 360 Jefferson City, MO 65102 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washing ton, D.C. 20555 4

bec D. Shafer/A160.761

/QA Record (CA-758)

Nuclear Date E210.01 DFS/ Chrono D. F. Schnell J. E. Birk J. V. Laux j M. A. Stiller l G. L. Randolph l R. J. Irwin l H. Wuertenbaccher W. R. Campbell A. C. Passwater R. P. Wendling l D. E. Shafer l D. J. Walker i O. Maynard (WCNOC) j N. P. Goel (Bechtel) l P. Sharkey T.

NSRB (Sandra Auston) l T. M. M l

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