ML20117M599

Forwards Relief Requests CR-17 & CR-18 Addressing Sections IWB-2500 & IWC-2500

ML20117M599
Person / Time
Site:	LaSalle
Issue date:	09/04/1996
From:	Subalusky W COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9609170552
Download: ML20117M599 (12)

Text

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. Commonwralth Edison Company

. lasalle Generating Station 24)I North 21st Road Marseilles. II. 613 i1-9757 Tri ais.3s 6:6i l

i September 4,1996 i

United States Nuclear Regulatory Commission ,

Attention: Document Control Desk Washington, D.C. 20555

Subject:

LaSalle County Nuclear Power Station Units 1 & 2 Submittal of Relief Requests CR-17 and CR-18 NRC Docket Nos. 50-373 and 50-374 LaSalle County Station performs In-Service inspections in accordance with ASME Section XI,1989 Edition. The enclosed relief requests address sections IWB-2500 and IWC-2500.

Sections IWB-2500 and IWC-2500 require surface examination of integrally welded attachments. Relief request CR-17 requests relief from the Code Required surface examinations on several of these integral attachments.

I Section IWB-2500 also requires surface examination of both the inside and outside surfaces of the attachment weld between the Reactor Pressure Vessel, and the Reactor Pressure Vessel support skirt. Relief Request CR-18 requests relief from the Code Required surface examination of the inside surface of this attachment.

Relief requests CR-17 and CR-18 are applicable to both Units 1 & 2.

Comed requests that approval of these mquests by September of 1997. In addition, Comed requests that the relief extend throughout the remainder of the Second 10-Year in-Service Inspection Interval.

p y/7 ' ,

O A Unicom compan3

if there are any questions or comments conceming this letter, please refer them to me at (815) 357-6761, extension 3600.

Respectfully, f

1 W. T. Subaluskyg j -~-

Site Vice President LaSalle County Station Enclosure cc: A. B. Beach, NRC Region ill Administrator M. P. Huber, NRC Senior Resident inspector - LaSalle D. M. Skay, Project Manager - NRR - LaSalle F. Niziolek, Office of Nuclear Facility Safety - IDNS DCD - Licensing (Hardcopy: Electronic: )

Central File l

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Revision 0 RELIEF REQUEST NUMBER: CR-17 (Page 1 of 6 )

COMPONENT IDENTIFICATION Code Classes: 1 and 2

References:

IWB-2500, Table IWB-2500-1, Figure IWB-2500-15 IWC-2500, Table IWC-2500-1, Figures IWC-2500-5(a) i' Examination Category: B-K-1, C-C Item Number B10.10, C3.20

Description:

Examination of Integrally Welded Attachments to Piping Component Numbers: See Tables CR-17-01 and CR-17-02.

CODE REQUIREMENT Section XI, Table IWB-2500-1, Examination B-K-1, item B10.10 requires a surface l examination of the welds and adjacent base metal as defined by Figure IWB-253>15.

Section XI, Table IWC-2500-1, Examination C-C, item C3.20 requires a surface examination of the welds and adjacent base metal as defined by Figure IWC-2500-5(a).  ;

BASIS FOR RELIEF Pursuant to 10 CFR 50.55a(a)(3)(ii), relief is requested on the basis that compliance with the Code requirement vould result in hardship or unusual difficulty without compensating increase in the level of quality and safety.

The subject welded attachments are of the T joint double bevel groove weld design such that one of the weld surfaces, surface area C-D, is located inside the flued head penetration assembly. The configuration of these components are shown on Figures CR-17-01 and 02. A surface examination on both surface areas A-B and C-D is  !

required on components in categories B-K-1 or C-C.  !

Due to limitations imposed by the design and construction of these penetration assemblies, the code required surface examination cannot be performed on surface area C-D. Access to surface area C-D from the outside (closed) end of the penetration assembly is not possible due to the presence of the integral attachment. Additionally, the distance to the integral attachment from the inside (open) end of the penetration assembly, coupled with the limited clearance between the process pipe and the penetration sleeve prevents the performance of the required surface examination on surface area C-D. Typically, this distance is between 54 & 78 inches. Table CR-17-01 and -02 provide additional detailed dimensions for the subject penetration assemblies.

Each of the components listed on Table CR-17-01 and -02 are parts of assemblies which penetrate primary containment, secondary containment, or walls. To satisfy the Code requirement, redesign of the piping and/or penetrations to provide access to the subject surface areas would be required. Significant engineering, installation costs, and radiation exposure would be incurred by LaSalle station to implement these 1

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Revision 0

.- RELIEF REQUEST NUMBER: CR-17 1 Page 2 of 6)  !

BASIS FOR RELIEF (Cont.)

modifications without a compensating increase in the level of quality or safety because l (1) the code required surface examination on surface area A-B and (2) the periodic VT- l 2 examinations as required by ASME Section XI, Categories B-P or C-H will provide l 7

reasonable assurance of continue structuralintegrity of the subject components. l Based on the above reasons, relief is requested from performing the Code required

surface examination on inaccessible surface area C-D for the subject components. j 1 PROPOSED ALTERNATE EXAMINATION 4

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- For the reasons previously discussed, alternate examination is impractical for surfaca l

area C-D.

However, LaSalle Station will perform a surface examination on the accessible surface  ;

area A-B in accordance with the requirements of ASME Section XI Category B-K-1 or j C-C. Additionally, a VT-2 visual examination around the annulus of the penetration will 4

be performed in conjunction with the system pressure tests required by ASME Section i t XI,- Category B-P or C-H. 1 APPLICABLE TIME PERIOD Relief is requested for the second ten-year inspection interval of the Inservice i

inspection program for LaSalle Units 1 and 2.

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Redsion 0

. RELIEF REQUEST NUMBER: CR-17  !

(Page 3 of 6) -

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Table CR-17-01 I

UNIT 1 INTEGRALLY WELDED ATTACHMENTS l

CLASS ATTACHMENT / PROCESS PIPE FLUED HEAD ID l PENETRATION ID OD 1 M-7 20" 32.25" 1 M-8 12.75" 19.75" 1 M-9 12.75* 19.75" l 1 M-10 12.75" 19.75" 1 M-11 12.75" 19.75" 1 M-12 12.75" 19.75" 1 M-13 ,

12.75" 19.75" 1 M-14 12.75" 19.75" 1 M-2:! 3.5" 20.75" ,

1 M-25 6.625" 11.50" 1 M-30 6.625" 19.50" 1 M-34 1.9" 8.75" 2 1RB-157 18" 23" 2 1 RB-17 8.625" 15.25" 2 1 RB-77 18" 25.25 2 M-68 24" 30.75" ,

2 M-69 24" 30.75" 2 M-70 24" 30.75" 2 M-71 24" 30.75" 2 M-72 24" 30.75" 2 M-79 16" 20" l 2 M-84 16" 18" l 1

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Revision 0

, RELIEF Rs_ QUEST NUMBER: CR-17 (Page 4 of 6)

Table CR-17-02 UNIT 2 INTEGRALLY WELDED ATTACHMENTS CLASS ATTACHMENT / PROCESS PIPE FLUED HEAD ID PENETRATION ID OD 1 M-7 20" 32.25" 1 M-8 12.75" 19.75" 1 M-9 12.75" 19.75" 1 M-10 12.75" 19.75" 1 M-11 12.75" 19.75" 1 M-12 12.75" 19.75" 1 , M-13 12.75" 19.75" 1 M-14 12.75" 15.75" 1 M-22 3.5" 20.75" 1 M-29 6.625" 11.50" 1 M-30 6.625" 19.50" 1 M-34 1.9"" 8.75" 2 2RB-210 18" 23" 2 2RBS1 8.625" 15.25" 2 2RB-97 18" 25.25 2 M-68 24" 30.75" 2 M-69 24" 30.75" 2 M-70 24" 30.75" 2 M-71 24" 30.75" 2 M-72 24" 30.75" 2 M-79 16" 20" 2 M-84 16" 18" i

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Revision 0 RELIEF REQUEST NUMBER: CR-17 (Page 5 of 6)

Figure CR- 17-01 I

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l Revision 0

. RELIEF REQUEST NUMBER: CR-18 (Page 1 of 4)

COMPONENT IDENTIFICATION Code Class: 1

References:

IWB-2500, Table IWB-2500-1, Figure IWB-2500-13 Examination Category: B-H ltem Number B8.10

Description:

Examination of Reactor Vessel Support Skirt to Reactor ,

Vessel Bottom Head Weld Component Number Unit 1 - IVS-1 Unit 2 - IIVS-1 CODE REQUIREMENT Section XI, Table IWB-2500-1, Examination B-H, item B8.10 requires a surface examination of the weld and adjacent base metal as defined by Figure IWB-2500-13.

BASIS FOR RELIEF l

Pursuant to 10 CFR 50.55a(a)(3)(i), relief is requested on the basis that the proposed alternatives would provide an acceptable level of quality and safety.

The reactor vessel bottom head was constructed with a weld build-up around the circumference of the head that was designed as the attachment point for the reactor vessel support skirt. This weld build-up was machined and heat treated along with the l reactor vessel.

The support skirt is attached to the weld build-up by means of a full penetration butt  ;

weld. As can be seen in Figure CR-18-01 and -02, the design of this weld is such that the code required surface examination on surface area C-D of Figure IWB-2500-13 is limited by the short blend radius (1" R for Unit 1,3" R for Unit 2) and the steep angle formed by the bottom head support skirt that limits access to surface area C-D.

Additionally, inspection personnel would be exposed to high radiation field when conducting the code required surface examination on surface area C-D. The estimate radiation exposure can be up to 2.4 person-rem for an inspection team of two (2) persons based on radiation field of 600 mR/ hour for 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> examination time. It is further estimated that an additional 3 person-rem would be incurred by craft support personnel to prepare area C-D for the code required surface examination. The radiation field on the outside of the support skirt is approximately 25 mR/ hour.

Based on dimensions provided on fabrication drawings, a best effort ultrasonic examination using a combination of various angle beams, such as 0*,30', and/or 45*,

can be performed from the outside surface of the support skirt. This volumetric examination is expected to detect service induced flaws initiated from most of surface area C-D. The performance of this volumetric examination in conjunction with the performance of the Code required surface examination on surface area A-B will provide adequate assurance of the structuralintegrity of the subject weld.

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1 Revision 0 RELIEF REQUEST NUMBER: CR-18 (Page 2 of 4)

BASIS FOR RELIEF (Cont'd)

For these reasons, LaSalle Station requests relief from the ASME Section XI, surface examination of surface area C-D of Figure IWB-2500-13.

PROPOSED ALTERNATE EXAMINATION As an alternate examination to the Code required surface examination of surface area C-D, LaSalle Station will perform a best effort ultrasonic examination of the C-D region from the outside surface of the support skirt. The volumetric examination frequency will .

be in accordance with that required by Category B-H, item B8.10.

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The Code required surface examination of the surface area A-B will be performed in  !

accordance with the requirements of Category B-H, item B8.10.

APPLICABLE TIME PERIOD 1

Relief is requested for the second ten-year inspection interval of the Inservice i inspection program for LaSalle Units 1 and 2.

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l RELIEF REQUEST NUMBER CR-18 (Page 3 of 4)

Figure CR-18-01 REACTOR VESSEL SUPPORT SKIRT ATTACHMENT WELD UNIT 1 i i

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RELIEF REQUEST NUMBER CR-18 (Page 4 of 4)

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