ML20073K390
| ML20073K390 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 09/30/1994 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9410110204 | |
| Download: ML20073K390 (7) | |
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.PECo Energy Cornpany Nuclear Group Headquarters 965 Chesterbrook Boulevard i
Wayne. PA 19087-5691 September 30,1994 Docket No. 50-353 License No. NPF-85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Subject:
Limerick Generating Station, Unit 2 Request Relief for First Ten Year Interval inservice Inspection Program Regarding Dry Welding Requirements Gentlemen Attached for review and approval is Relief Request No. RR 18 for the Limerick Generating Station (LGS), Unit 2, First Ten Year Interval inservice inspection (ISI) Program. Relief Request No.
c RR-18 requests relief from the requirements of Subsection lWA-4000 of Section XI of the.
American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code, 1986 Edition, which requires that repairs be performed in accordance with a program that
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delineates the essential requirements of the complete repair cycle. Welding operations, which is an essential part of the repair cycle, are to be perfomed in accordance with a Welding Procedure Specification (WPS) by qualified welders which have been qualified as required by.
Section XI of the ASME Code.Section XI, Subsection IWA-4000, of the ASME Code stipulates that welding operations are to be conducted in accordance with the original design Code (l.e.,
i ASME Code, Section 111,1971 Edition. and installation Code, Section lit,1974 Edition). These 1971 and 1974 Editions of the desigr, Codes stipulate that welding should not be performed on wet surfaces.
PECO Energy Company is requesting relief from the ASME Code requirements specifying that l
welding operations not be performed on wet surfaces. This relief is needed to support installation of Unit 2 plant system modification designed to increase the spent fuel storage capacity in the Spent Fael Pool. A portion of this modification involves cutting and rerouting a section of 12' piping, and as a consequence, two (2) additional welds will be necessary. Due to the location and piping configuration these welds must be performed underwater. Therefore, welding on a dry surface as required by the ASME Code would b6 considered a hardship. In.
lieu of performing the welding operations for these (2) welds in accordance with the ASME Code requirements, we propose to implement the requirements specified in Code Case N-516,
" Underwater Weiding,Section XI, Division 1," which establishes the criteria for welding '
underwater.
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t 9410110204 940930 (j
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September 30,1994 Page 2 J
This modification work is currently in progess and any welding must be deferred until reflef is.
-i grarted. The details and justification for relief are explained further in the attached Relief Request. We would appreciate your cooperation in providing an expeditious review of Relief Request No. RR-18, and request that the NRC Orant relief from the ASME Code requirements that welding only be performed on dry surfaces by October 15,1994.
If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours, e
G. A. Hunger, Jr.
Director - Ucensing Attachment i
cc:
T. T. Martin, Administrator, USNRC, Region I (w/ attachment)
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N. S. Perry, USNRC Senior Residert inspector, LGS (w/ attachment) i 4
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i Limerick Generating Station, Unit 2 First Ten-Year interval inservice Inspection Program RELIEF REQUEST NO. RR-18 e
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l Docket No. 50-353 Page 1 of 4 i
Umerick Generating Station, Unit 2 4
REUEF REQUEST NO. RR-18 i
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1.
IDENTIFICATION OF COMPONENTS 12" Class 3, Residual Heat Removal (RHR) piping (Line HCC-204), associated with i
Modification 6118.
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11.
CODE REQUIREMENTS FROM WHICH RELIEF IS REQUESTED ASME Code,Section XI,1986 Edition, lWA 4000 requires repair operations to be performed in i
accordance with a program delineating the essential requirements of the complete repair cycle.-
i Welding, an essential item in the repair cycle, is to be performed in accordance with a Welding Procedure Specification (WPS) by qualified welders which have been qualified by the Owner in accordance with the requirements of ASME Code,Section IX.
Additionally, ASME Code,Section XI,1986 Edition, Article IWA-4000 requires weiding to be j
conducted in accordance with the original design Code, ASME Code, Section 111,1971 Edition, and i
-installation Code, Section Ill,1974 Edition.
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I performed on wet siirfaces.
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Paragraph 144412 of the 1971 and 1974 construction Codes require that welding shall not be 5
j Relief is requested from these dry welding requirements.'
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BASIS FOR REUEF Modification 6118, (Unit 2 Spent Fuel Pool Rerack), requires the cutting and rerouting of 12" piping i
spool HCC-204-4-2, and as a consequence, welds W-1201 and W 1301 will be added. Becat,ise of j
the configuration and location of the particular applicable components, welding on a dry surface would be a hardship.
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The piping in question is In the Spent Fuel Pool and underwater. This specif!c request is mada for permission to use ASME Code,Section XI Code Case N-516 to satisfy the requirements for 1
underwater welding on this particular modification.
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l Docket No. 50-353 Page 2 of 4 l
Umerick Generating Station, Unit 2 l
RElJEF REQUEST NO. RR-18 l
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(Continued)
IV.
ALTERNATE PROVISIONS In lieu of welding in accordance with the requirements ASME Code,Section XI, Article IWA-4000, Limerick Generating Station requests approval to make two (2) welds in a Class 3 system of Unit 2 by welding under water in accordance with the requirements of Code Case N-516. The welds to be made are butt welds in austenitic stainless steel usir'3 austenitic stainless steel backing rings and welding material.
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o Repair or replacement of P-No.8 and P-No. 4X materials and associated welds may be performed underwater provkied the welding procedures and welders or welding operators are qualified in accordance with Section IX and the additional essential variables of para.
2.0 or 3.0, as applicable.
o Welding Procedure Specifications for wet underwater welding shall be qualified to the requirements of Section IX for groove welds. The following variables also apply:
(a)
Additional essential variables:
(1) a change in the method for underwater transport and storage of filler material (2) addition or deletion of waterproof or supplementary coatings for the filler metal or a change in the type of any waterproof or supplementary l
coatings; (3) a change in electrode diameter beycad the range used in qualification; (4) a change in depth beyond that qualified in accordance with Table 2.1-1 of Code Case N-516; (5) a change in the SFA specification AWS filler metal classification, or, if not conforming to an AWS filier metal classification, a change in the manufac-turer's trade name for the electrode or filler metal; (6) addition of welding positions other than those qualified.
(7) a change from upward to downward, or vice versa, in the progression specified for any pass of a vertical weld; (8) a change from the stringer bead technique to the weave bead technique, or vice versa, in the vertical position; (9) a change from ac to do, or vice versa; and, in dc welding, a change in polarity; (10) a change from wet backside to dry backside for backing thickness less than 1/4 in.
(b)
Additional nonessential vsrlables:
(1) an increase in time of electrode exposure to water; (2) a decrease in included angle, a decrease in root opening, or an increase in root face.
i Dock:t No. 50-353 Page 3 of 4 Litrerick Generating Station, Unit 2 RELIEF REQUEST NO. RR-18 l
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Welders and welding operators for wet underwater welding shall be quallfled in accordance j
with Section IX and the variables listed below. When a welder or welding operator has not welded with a process in a wet underwater environment for at least six months, the qualifications for that underwater process shall expire.
(a)
A change in the SFA specification AWS filler metal classification.
(b)
Addition or deletion of waterproof or supplementary coatings for the flifer metal or a change in the type of any waterproof or supplementary coatings.
(c)
A change from salt or borated water to fresh water.
(d)
Use of a larger diameter electrode than that used during performance qualification.
(e)
A change in depth beyond that qualified in accordance with Table 2.1-1.
(f)
Addition of welding positions other than those qualified in accordance with Table 2.1-2 of Code Case N-516.
(g)
A change in polarity or type of power source (e.g., rectifier, motor-generator, I
inverter).
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A change from stringer bead to weave technique.
(i)
A change in welder's view from beneath to above the water surface.
(j)
A decrease in the included angle, a decrease in root opening, or an increase in the root face.
o Each filler metal heat, lot, waterproof coating type, and supplementary coating type to be used in production shall be tested in accordance with the following requirements:
(a)
Using the production widing process, an all-weld-metal coupon in accordance with SFAS.4 will be prepared at a depth such that the depth of the production weld will be within the depth limitations of Table 2.1-1 of Code Case N-516.
(b)
The coupon shall be tested as follows:
(1) directly measure the fenite number for austenitic stainless steel,Section IX, QW-442 A-No. 8 filler metal; (2) perform a tension test on one all-weld-metal specimen.
(3) determine as<!eposited chemical composition in accordance with the applicable SFA specification.
(c)
Acceptance criteria:
(1) the ferrite number shall meet the requirements of the Construction Code; (2) the ultimate tensile strength shall meet the minimum tensile strength specifiert for either of the base metals to be joined; (3) the chemical composition shall meet the applicable SFA specification requirements for the as deposited chemical composition.
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Docktt No. 50-353 Page 4 of 4 l
Umerick Generating Station, Unit 2 l
REUEF REQUEST NO. RR-18 Hev.0 l
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o A confirmation weld shall be produced at the underwater location before production welding. This weld shall be used by the repair organization to confirm that the welding system is functioning property. If it is not practicable to perform the confirmation weld at the actual location (e.g., because of ALARA concerns), it shall be performed at j
another location under similar underwater conditions. The qualified welding procedure, as amended below, shall be used for the confirmation weld.
I (a) a confirmation weld shall be made with each welding system used in production; (b) for material less than 1/4 in thick, the confirmation weld shall simulate the production weld joint pressure differential and wet or dry backside conditions; (c) the confirmation weld shall be made in one of the positions to be used in productions; (d) the confirmation weld shall be at least 6 in. long or shall simulate the production weld length.
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o Procedure qualification at the underwater location may be substituted for the confirmation weld.
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When it is impractical to perform the examination required by this Division or the l
Construction Code because of the underwater environment, the following alternative requirements shall be met. Acceptance criteria shall be in accordance with the 1
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requirements of this Division or the Construction Code. The remote visual examinations i
in (a) and (b) below shall be demonstrated to have sufficient sensitivity to detect Indications rejectable by the surface examination acceptance criteria.
j (a)
The cavity, after defect removal, shall be visually examined remotely at a minimum of SX, in lieu of any required surface examination and evaluated using surface examination acceptance criteria.
(b)
The weld shall be visually examined remotely at a minimum of SX, in lieu of any j
required surface examination and evaluated using surface examination acceptance criteria.
(c)
The weld may be ultrasonically examined using a procedure qualified for the underwater environment in lieu of any other required volumetric examination.
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