ML20248E483

Forwards Addl Info to Support 10CFR50,App J Exemption to Allow Leaving Leak Chases Plugged During Type a Integrated Leak Rate Test

ML20248E483
Person / Time
Site:	Callaway
Issue date:	09/29/1989
From:	Schnell D UNION ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20248E486	List: ML20248E483 ML20248E488
References
ULNRC-2083, NUDOCS 8910050250
Download: ML20248E483 (9)

Text

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1901 Grctiot Street

. Post Office Box 149.

- St Louis, Missouri 63166;

'314-554-2650.

m September 29, 1989 . DonaldF. schneII IEtecraic; ' Senior Mce President uva.

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U.S. Nuclear: Regulatory Commission Attn: Document Control Desk Mail Station.P1-137 Washington, D.C. 20555 ULNRC-2083 Gentlemen:

DOCKET NO. 50-483

.CALLAWAY PLANT INTERPRETATION TO LEAVE LEAK: CHASES PLUGGED DURING AN' INTEGRATED LEAK RATE TEST (ILRT) l

References:

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

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

3) ULNRC-1945, dated March 20, 1989

4) T.W. Alexion letter'to D.F. Schnell dated July 31, 1989 References 1 and 3 requested the NRR staff to review the interpretation that the combined liner. butt weld along with'the associated pre-tested channel fillet welds I 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).

Reference 4 requested additional information to support a 10CFR50, App. J exemption to allow leaving the leak chases plugged during a Type A ILRT. This information is provided as an attachment to this letter If you have any questions, please contact me.

Very truly yours, I

8910050200 890929 FDR ADOCK 05000483 FDC Donald F. Schnell WEK/ dis j 01 Attachments l

b____ __ _ _ _ -- _ . _ _ _ .J

cc:. Gerald Charnoff, Esq. .

Shaw, Pittman, Potts & Trowbridge 2300'N. Street, N.W.

Washington, D.C. 20037 Dr.:J. O. Cermak 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 U.S. Nuclear Regulatory Commission RR#1 Steedman, Missouri 65077 Tom Alexion (2)

Office of Nuclear Reactor Regulation -

U.S. Nuclear Regulatory Commission

1. White' Flint, North, Mail Stop 13E21 11555 Rockville Pike Rockville, MD 20852 Manager, Electric Department i Missouri Public Service Commission P.O. Box 360 '

Jefferson City, MO 65102 Ron Kucera Department of Natural Resources P.O. Box 176 Jefferson City, MO 65102 i

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bcc: D. Shafer/A160.761

/QA. Record (CA-758) W[A Nuclear Date E210.01 DFS/ Chrono D. F. Schnell J. E. Birk J. V. Laux W/A M. A. Stiller G. L. Randolph R. J. Irwin H. Wuertenbaecher W. R. Campbell W[A A. C. Passwater R. P. Wendling D. E. Shafer D. J. Walker O. Maynard (WCNOC)

N. P. Goel (Bechtel)

T. P. Sharkey NSRB C n1. (Sandra D ,vig ,,,,+/sAuston)lA W

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n ATTACHMENT TO ULNRC-2083 ADDITIONAL INFORMATION REGARDING 10CFR50, APPENDIX J EXEMPTION REQUEST (Leak Chases)

NRC Question 1. Provide supporting analyses and stress calculations for at least one typical leak chase channel to show that the containment liner leak chase channel system meets the following requirements:

a. The weld material strength and quality of weld attaching the channel to the liner plate should be equal to or better than that of the original liner joints and should meet the applicable requirements of either ASME Boiler and Pressure Vessel Code,Section III, Division 2, Subsections CC-2000, 3000 and 4000 (Code of Concrete Reactor Vessels and Containments, 1983),

or whatever comparable code that was used in design and construction.

Union The leak chase channel system was installed by Electric Chicago Bridge and Iron (CBI) as a non-safety Response related portion of the containment liner (also constructed by CBI). The fabrication and installa-tion of the leak chase system was performed under the same construction specification (C-151 and C-151A) as the fabrication and erection of the containment liner. The general notes for the construction of the liner restricts all field welds to E7018 or E6010 weld rod, with no exceptions mentioned for the installation of the leak chase channel. Therefore, it is reasonable to conclude that the same welding material used for the pressure boundary joints of the liner was used for the fabrication of the leak chase channel system.

l Since these channels were installed as non-safety l related, there are no weld control records that document the actual material used. However, where portions of the liner required repair (including the repair of channel), the repair plan specified the welding material to be used. This material was L consistent with the general notes regarding permissible weld rod types. The construction specifications for the containment liner also specified that proper controls would be taken for the storage of welding rods to ensure that there was no degradation of the material. Again, there are no exceptions stated allowing lesser controls for the welding material that was to be used on the leak chases. Consequently, it can be reasonably concluded that the material used to attach the weld channel to the liner was the same material used for i Page 1 of 6

the welding of the liner pressure boundary joints (thus material quality and strength would be the same as the liner pressure boundary joints).

In regard to meeting the requirements of CC-2000, and 4000;'the leak chase system was constructed to the 1974 code (Division 1, subsection NE).

Section NE-2000 is the sane for welding material requirements with the exception that further restrictions on the use of electroslag welding is introduced in the CC subsection. This type of welding was not used on Callaway's liner and is therefore not an issue. The requirements imposed by subsection CC-2000 for material certification and material testing of the weld rods cannot be verified since there is no safety related documentation for the non-safety related welds.

The weld design does meet the requirements of subsection CC-3000. The configuration is an H joint as defined by section CC-3840, and identical (in form and size) to the weld of figure CC-4542.2-6(a).

NRC Question 1.b. Since the leak chase channels now become part of the containment wall and are therefore considered a structural element, the strength of the channel box and its welds should be able to resist all load combinations involving the tested loads and the loads of a postulated accident, including seismic loads. The design of the leak chase channel should meet the applicable requirements of steel containments; i.e., either ASME Boiler and Pressure Vessel Code,Section III, Division 1, Subsections NE-2000, 3000 and 4000 for Class MC Components (1983) and American Institute of Steel ,

Construction Specification for the Design, Fabrication and Erection of Structural Steel for Buildings (1978), or whatever comparable code that was used in design and construction. 1

)

Union The response to this question (included as an Electric attachment to this letter) is in the form of an Response engineering analysis. This analysis concludes that the callaway containment liner leak chase system meets the design requirements of ASME Subsection III for all pressure boundary loading applications.

NRC Question 2. Complete documentation of installation records, including leak test procedures and results of the liner seam welds and the welds attaching the channel to the liner, should be available onsite. Please summarize and Page 2 of 6 w _ _ . _ _ _ _ _ - - - _ _ _ _ - - _ .

provide examples of available records. If-no records or only partial records are available,-

as suggested in your March 20, 1989 letter,-

provide whatever additional information/ assurance is available regarding procedures, materials, welds, inspection records, etc.

Union, The installation was not.for a safety related-Electric system, therefore complete documentation as Response required by ASME subsections CC-2000, 4000, and NE-2000, 4000 is not available. Design documents and other documentation exist which provide.added assurance of the quality and type of material used.

Each leak chase system was required to be 100%-

halogen leak tested. The leak chases were divided

'into test zones with each zone numbered and identified on design drawings (See C151-739, attached as an example). Each of these zones was pressurized to 9 psig with air and checked for leaks. After the air test, each zone was then pressurized to 5 psig with a halogen mixture (using Refrigerant 12) and checked for leakage with a halogen sniffer. The acceptance criteria was 0.0001 scc /sec. These leak tests provide assurance that the existing welds were performed with sufficient quality to ensure the capability of each zone and each weld to act as a pressure boundary.

The leak test procedure that was used and the documentation of 100% acceptability for all the leak chase zones are included as attachments to this letter.

Assurance as to the type of material used can be provided by the existing design specifications, drawings and some construction documentation.

Bechtel construction specifications C-151 and C-151A were the specifications used to build the containment liner. These documents specify the acceptable material for shapes, welding material, control of welding material and requirements for welder qualification (per ASME section IX). The only exception taken from these specifications was for the requirements of test channels to meet the vendor's QA program.

For example, a typical channel shape (part number 69-1) is required to be made of A36 (SA36) material per the construction specification C-151. The design drawings identify the type of channel to be used by specifying a design detail. C-151-740 lists part number 69-1 as a test channel for the Page 3 of 6

perimeter-of-the liner floor. Drawing C-151-744 _

then identifies part number 69-1 as an L-2X2X1/4 channel made of A36 material. This'is further shown on the Final Bill of Material to be made of

!V A36 material. And finally, a shipping order for.

g some of this. material is available specifying'that 9 A36 material be: ordered. The' pieces were individually fabricated 1and shipped-to the Callaway.

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site. The. receiving report that accompanied some of the.69-1 pieces attests that.the material is A36 c

material.(from the' Material Heat _ Number' Sheet) and is certified by the shop ~ to be manufactured to; the required specifications on the Shop Release for Shipment check List.

Other channel p'i eces have traceability tio a CMTR, for example a CMTR'from Connors Steel Company

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identifies piece number 69-12 as A36 material and provides the code required physical'and-chemical test information. However,-not all material received for.the channel system can be traced'to a heat number, and of that which'is, not all the CMTRs provide a complete analysis of the material (the CMTR for-piece 70-19, heat 16634, does not provide the' physical property information, only the chemical analysis). In addition, a=particular piece installed in.the field cannot necessarily be identified to a CMTR. For example, the Final Bill-of Material requires 1800 feet of piece 69-12, but only 1320 feet can be traced to heat number 21934 (per the Daily Fabrication Report).

Therefore, for any given piece number 69-12 installed in the field there is a 73% probability (1320/1800) that the piece is made from heat number 21934.

Although all the material used for the leak chase system cannot be traced to a CMTR, those pieces y that are traceable provide added assurance that the i material used was in fact the material specified by the design documents. Also,'the material required is readily available and can be assumed to be the material that was actually installed.

The only welding materials permitted for field fabrication of the liner are E7018 and E6010 electrodes (per the general notes for construction, drawing C151-703). No exceptions are stated for the leak chase system. This information is supported by documentation available for repairs or non-conformances involving the leak chases. A copy of a repair checklist specifying that E7018 weld l

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L material be used in welding the affected leak l

chases is attached. The size of the weld is specified on the design drawings showing the channel detail. No other documentation identifying weld type or size is available for the non-safety related welds.

A review of the receiving documentation associated with the construction of the containment indicates that all welding material received by CBI was traceable to a CMTR via a heat number. The CMTR provides the code required tensile and chemical property information. The requirement for impact testing per NE-2420 is not applicable due to a thickness of less than 5/8" for the channel and liner. An example of this documentation is attached. It can then be assumed that even though a weld cannot be traced to a particular heat or lot number, the material that was used to make the weld was probably initially received as code material.

Based upon the above examples, there is sufficient assurance that the material specified on the design drawings was procured as indicated on the Bill of Material, shipping orders, etc., and installed as shown on the design drawings. Due to the fact that.

only two types of welding materials were allowed, it is reasonable to assume that no other types were issued for use on the containment. When on site for construction, CBI controlled their own welding material which was not issued with material used by the principle construction contractor (Daniel International). Assuming that the only welding material received was identified in the CBI receiving documentation, it may be concluded that the only welding material available on site for the CBI welders was received as code material.

The sections of ASME CC and NE regarding materials and fabrication (2000 and 4000) cannot be supported with documentation for the non-safety related installation. However, the documentation that does exist provides assurance that the leak chase system was procured and fabricated in accordance with design. All the materials used are equivalents to the SA counter parts permitted by ASME subsection NE, and the welding materials were required to be ASME SFA materials per the design specification.

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NRC Question 3. The staff needs a commitment that you will perform a visual inspection of the accessible interior and exterior surfaces of the containment structure and components prior to any Type A test, including a visual inspection of accessible channel plugs, as required by 10 CFR Part 50, Appendix J.

Union The' procedure for_ conducting a Type A test will be Electric revised to require an inspection of all accessible l Response leak chase channel test connections prior to I

starting pressurization of the containment.

As stated in Reference 3, the majority of the leak chase channel is on the liner floor (the actual channel being under 18 inches of concrete). Only a small percentage of test channel is exposed to the containment atmosphere. The concrete that covers the liner floor will act to protect the leak chase channels underneath by preventing significant degradation of the channel to take place. The initial halogen leak tests performed would then be indicative of the pressure retaining capabilities of the leak chase channels. Of the welds on the liner shell, less than 2% are covered with leak chases. Of those chases on the shell that are inaccessible, most of the actual channel can be visually inspected to verify no degradation of the channel has taken place (again verifying the validity of the initial halogen leak test).

Most of the test connections that are inaccessible are on the liner floor behind the bioshield. Therefore, any activity to vent these test connections would result in a significant amount of personnel exposure. These test connections have also been covered with the finishing of the concrete or have had support plates installed over them. Some of these plates support primary piping (resulting in significant cost to remove the support and uncover the test connection). The test connections for the liner in the instrument tunnel would require an entry into a very high radiation zone. Other test connections are located under the pad for the reactor coolant pump, steam i generator, and cross over leg supports. To vent all these connections would involve significant cost in terms of manhours and materials as well as radiation exposure in high and very high l radiation areas.

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