U-602638, Forwards Revised Relief Request Re Performance of NDE of Welds & Components for First 120-month ISI Interval

Forwards Revised Relief Request Re Performance of NDE of Welds & Components for First 120-month ISI Interval

ML20129E127
Person / Time
Site:	Clinton
Issue date:	09/20/1996
From:	Lyon M ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L30-96(09-20)LP, L30-96(9-20)LP, U-602638, NUDOCS 9609300299
Download: ML20129E127 (5)

Text

1

= a~

'D J,

• Uhnois Power Company Chnton Power Statvan P.O. Box 678 t

Chnton. IL 61727 ,

Tel 217 935-8881 U-602638 L30 96(09'.' 20 )t p 8E.100c September 20, 1996 Docket No. 50-461 Document Control Desk 10CFR50.55a Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Revision of ASME Section XI Relief Reauest for Clinton Power Station

Dear Madam or Sir:

By letter dated June 5,1996 [ Illinois Power (IP) letter U-602566), IP submitted several requests for relief from the requirements of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,1980 Edition through  !

Winter 1981 Addenda, with regard to the performance of non-destructive examination of J welds and components for the first 120-month inservice inspection interval for Clinton Power Station (CPS). One of the relief requests, No. 4008, was a request to allow a reduction in the required surface examination area for certain welds associated with integral attachments on piping in the Main Steam and Reactor Recirculation system (Code Class 1, Category B-K-1, Item B10.10), and to permit use of ASME Section XI Code Case N-509 which would allow a sample of attachment welds to be examined in lieu of examining all of the welds for shock suppressor lugs attached to the bowls of the CPS "A" and "B" Reactor Recirculation pumps (Code Class 1, Category B-K-1, Item B10.20).

Currently, the NRC staffis completing its review of the relief requests submitted via IP letter U-602566, including Relief Request No. 4008. This relief request was recently discussed, in particular, via a telephone conference conducted on September 13, 1996. Based on that discussion, IP has determined that the relief request should be revised with respect to that part of the request addressing surface examination of the shock suppressor lug welds on the Reactor Recirculation pumps at CPS. Specifically, IP is removing all references within the relief request to ASME Section XI Code Case N-509. IP believes that surTicient justification can be provided to request relief from performing examinations of the shock suppressor lug welds for RR Pump B without requesting approval to utilize the Code Case. Further, discussion with the NRC staff has eg>

Q 1 \

9609300299 960920 PDR ADOCK 05000461

.q PDR 1

. U-602638 Page 2 confirmed that it is not appropriate to request use of Code Case N-509 for a specific type 3

or limited number of components because the , Code Case is intended to apply sample selection criteria to an overall examination schedule for Class 1,2 and 3 components, at a program level.

4 Revised Relief Request No. 4008 is accordingly attached. The relief request has i been revised as described above and to include additional information relative to 2 justification for the requested relief from examination of the RR Pump B lug welds. It is anticipated that this revision will facilitate the NRC staffs review and approval of Relief Request No. 4008 in the near future, consistent with IP's intent to receive approved relief

~,

in time to support the forthcoming refueling outage at CPS (scheduled to begin October 13, 1996).

Sincerely yours, Michael W. Ly Director-Licensing TBE/csm Attachment 4 cc: NRC Clinton Licensing Project Manager NRC Resident OfIice, V-690 Regional Administrator, Region III, USNRC Illinois Depanment of Nuclear Safety

Attachment to U-602638 Page 1 of 3 ILLINOIS POWER COMPANY Clinton Power Station ASME Section XI Relief Request RELIEF REQUEST 4008 (Revision 0)

Exanunation Category B-K-1, items B10.10 and B10.20 SYSTEM / COMPONENT (s) FOR WIIICII RELIEF (integral attachments for piping and pumps, respectistly),

IS RLQUESTED Code Class 1: (1) Piping Attachments / Lugs: Weld Numbers 1-MS-A 7PR-WA,1-MS-B-8-PR-WA,1-MS-C-8-PR-WA and 1-MS-D-7-PR-WA (for Main Steam system (MS) guide supports), and IRR-A-PR 1 WA (for Reactor Rectreulation system (RR) variable support); (2) Pump Attachments / Lugs: (Unnumbered) Welds for shock suppressor lugs attached to Reactor Recirculation Pump B bowl.

ASME Section XI,1980 Edition through Winter 1981 CODB REQUIREMENT Addenda, requires surface examination of welds for integral attachments during the first ten-> tar interval.

Relief for Item B10.10 is requested from performing a full CODE REQUIREMENF FROM WIIICif RELIEF IS surface examination of the identified welds for the MS and REQUESTED RR piping attachments / lugs as access to each of the examination areas is restricted dte to the associated cornponent suppons. For item B10.20, relief is requested from performing surface examination of any of the shock suppressor lug welds for RR Pump B.

For item B10.10: Performing the required surface BASIS FORRELIEF examination of the entire examination area for each of the welds associated with integral attachments or lugs on each of the main steam lin:s and on the RR Loop "A" suction line requires the removal / disassembly of four guide supports (one for each steam line) and one variable support (for the RR loop "A" suction line) in order to gain eccess to the required exanunation areas. For Item B 10.20: In order to perform the required surface examination of the shock suppressor lugs on Reactor Recirculation Pump B the entire insulation surrounding the pump bowl, which is located in a high radiation area, would hast to be remostd.

For Item B10.10: Perform a surface examination of each of ALTERNA1E EXAMINATIONS the weld areas to the maximum extent feasible without removal or disassembly of the associated component supports. Table I identifies the examination coverage feasible imed on examinations that have been completed to date and on what is projected to be done for the remaining welds to be examined in the next scheduled refueling outage. For item B10.20: Perform a surface examination of at least 50% of the total number of shock suppressor lug welds for RR pumps A and B.

For Item B10.10 - Main steam line attachments: Based on JUSTIFICATION FOR TIIE GRANTING OF the size, design and installation of the Main Steam guide RELIEF supports, disassembly and reassembly of these guide supports (one for each steam line) would be a complicated and tedious process, involving a diflicult procedure to implement. (A drawing of one of the main steamline guide supports is attached as Figure 1.) Further, although none of the guide supports were removed for any of the attachment weld examinations performed to date for the main steam lines, based on the presious disassembly of a similar guide support in another system, Illinois Power Company (IP) beliests that completion of the process would require replacing

1 l

• . Attachment to U-602638 Page 2 of 3 l

the Lubron plates for the supports, which are difficult to procure. The intent of the ASME Section XI examination is to I

prmide assurance of structural integrity rather than require disassembly and reassembly of properly functioning components / supports, possibly adversely affecting their operability. Disassembly of a properly functioning guide support j is thus notjudged to be prudent. In addition, due to the extensist effort required, disassembly and reassembly of the main  ;

steam line guide supports would likely extend the duration of the outage and result in unn~~=ry radiation exposure.

For item B10.10 Reactor recirculation piping attachment: The variable support for the associated Reactor Recirculation system pipe is a load-carrying support. In order to remme this support, a temporary support would be required to be installed. The variable support is located 13 feet above the floor elevation arx! is in a high radiation area. Several man-hours would hast to be expended to crect scaffolding, remme insulation, install a temporary support and transfer the piping load prior to remming the variable support. Further effort would then be required for system restoration. The total dose that would be incurred is estimated to be five (5) man-rem. Examining 65 percent of the weld area (to facilitate examination of the obstructed weld area for the attaciunent/ lug on the associated reactor recirculation line) should be suflicient to establish the integrity of the lug weld without significantly reducing the safety margin prmided by such verification.

For item B10.20 - Shock suppresser lugs on RR Pump B: IP has performed examination of all the welded attachments on RR Pump A (which is essentially identical to RR Pump B). 'Ihis is equivalent to 50% of the total number of welded attachments on both RR pumps (A and B). In order to perform the required surface enmination of the shock suppressor lugs on RR Pump B the entire insulation surrounding the pump bowl would hut to be renxwed and reinstalled after the examination. The total dose that would be incurred to perform this acthity is estimated to be 3 man-rem. Examining all of the welded attachments on RR Pump A, or 50% of the total number of attaciunent welds on both RR Pumps, will reduce the undue burden on IP (i.e., the cost in resources and man-tem) but still support the safety margin prmided by adequate verification and assurance of weld integrity for the RR pump shock suppressor lugs.

The requested reliefis for the first ten-year interval at CPS.

IMPLEMENTATION SCliEDULE l

J TABLEI CODE CATEGORY B-K-1 EXAMINATION COVERAGE l

I l

Estimated Percentage of Area Examined Due To Component Support (s)

Weld Number System Description Inte:ference IMS-A-7PR WA Main Steam 25 1MS-B-8PR WA Main Steam

• IMS C-8PR WA Main Steam 27 IMS-D-7PR-WA Main Steam 27 iRR-A-PR-1-WA Reactor Recirculation 65

• This item is scheduled for examination during the next refueling outage IP expects the percentage of area examined to be 25 to 27 percent.

, Attechment

. , , . to U-602638 Page 3 of 3 14 N

j r .. - .. N. , . - - -

Q.. - : . / ' .. . - _e ;

m g, I

/ wl  :

pI

< g;; AA.r DA r- 4 c L i i i i i -l D- f _J -f I g.

I_ .

g  :.

L "I 3 / ,  !/ .

. ;

! ! / -q 7  ! ! -l.>

lj%;k<___

j ,.

55

Y" ~.

$  !!j

..i 1.

l11 11 plI!!

d"! !s I

( c, -- .. / k ..-.. ).p l 8 'h_ ' '

gu h . .,

N $*f I $ 5 iO ..

8 - N, s

,,l ,

• I X

q:5 g-: -pg  :

S

, i lv.g = .- -.e-  :

w _

4 m .

,_ . l

~n q ,

q- _.. .-

j .. i  :

-[ -

F --

q.- -

. y-  ! ,

8

..'- w-

• -o_

e l

p s

.\ l e.t

'2h} ,,

9 -- g -- ,-

e -

m-:{-

i a.,/- k.

- , , .a  : .i s!' !t-~$

W I'_ I l up-

• (

E

~

\ '%.

. i

-#. i e y gd e t:

f- t

\=5

-+- );h_ht .&$ N) ,

f  !

Y q . -f t-  :