ML20083C010
| ML20083C010 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 05/04/1995 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9505150067 | |
| Download: ML20083C010 (7) | |
Text
Station Support Department o:
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PECO ENERGY 71Jaar:L,,
965 Chesterbrook Boulevard Wayne, PA 19087 4 691 May 4,1995 Docket Nos. 50452 50-353 License Nos. NPF 39 NPF-85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Subject:
Limerick Generating Station, Units 1 and 2 Revised Relief Requests for First Ten Year interval inservice inspection Programs i
Gentlemen:
Attached for review and approval are two (2) revised Relief Requests (i.e, Relief Request Nos.
RR-22 and RR 16) for the Limerick Generating Station (LGS), Units 1 and 2, First Ten Year interval inservice Inspection (ISI) Programs. These Relief Requests are being submitted to request relief from the requirements stipulated in Section XI of the American Society of Mechanical Engineers (ASME) Boller and Pressure Vessel (B&PV) Code,1996 Edition, regarding pressure tests for various Class 1,2, and 3 systems and pressure retaining components, which include 'Iping, pumps, and valves. Relief Request No. RR-22, Revision 1, applies to the LGS Unit 1 ISi, rogram (i.e., Specification NE-42), while Relief Request No. RR-16, Revision 1, pertains to the LGS Unit 2 ISI Program (i.e.. Specification NE-27). A brief description of each revised Relief Request is provided below.
Unit 1 Relief Reauest t
Relief Request No. RR-22, Revision 1 I
This Relief Request requests relief from the ASME Code requirements specified in Section XI, Subsection IWA-4400, which requires that an elevated pressure hydrostatic test be performed in accordance with the requirements of IWA-5000, following repairs by welding, or the Installation of replacement items by welding, on the pressure retaining boundary of Class 1,2, and 3 components. In lieu of performing the ASME Section XI pressure test, nondestructive examinations will be performed in conjunction with visual examinations (i.e., VT-2) and system pressure tests.
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unt 2 Remet _ Request i
Rollef Request No. RR 16 Revision 1 l
l This Rollef Request is identical to Relief Request No. RR-22 described above for Unit 1, which requests resist from the ASME Code requirements specNied in '
l Section XI, subeection IWA-4400, concoming elevated pressure hydrostatic testing in accordance with the requirements IWA-5000, after repairs by welding, j
or the installation of replacement items by welding, on the pressure retaining boundary of Class 1,2, and 3 components. This Relief Request also contains j
' the same altemale testing p,c/A. as described above for Relief Request No.
RR-22.
Revision 0 to Relief Request Nos.' RR-22 (Unit 1) and RR 16 (Unit 2) were originally submitted to~
i the NRC by letter dated September 27,1994, and are currently pending NRC review and approval. These Relief Requests have been revised to remove the specific plant system i
' references identified in Section I, " identification of Components," of each Relief Request. The..
basis for eliminating this information is that these Relief Requests should apply to aN Class 1,2, and 3 pressure retaining components subject to hydrostatic testing as required by lWA-4400 and
. lWA-5000, and not just those systems identified in Revision 0 of each Relief Request. Therefore,.
j Revision 1 to Relief Request Nos. RR-22 and RR-16 supersede those previously submitted by our letter dated September 27,1994, which are currently under NRC review.
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The specific detals and justification for relief are provided in the attached revised Relief Requests. This information was not changed from that previously submitted. We originally j
requested that the NRC review and approve these Relief Requests for the LGS, Units 1 and 2, ISI
-l Programs, by June 30,1995. We would appreciate the NRC's cooperation by reviewing these i
revised Relief Requests and granting necessary approvals by the same date.
If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours, G. A. Hunger, Jr.ge. a. A S.
Director. Licensing Attachments cc:
T. T. Martin, Administrator, USNRC, Region 1 (w/ attachments)
N. S. Perry, USNRC Senior Resident inspector, LGS (w/ attachments) e i
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i Limerick Generating Station, Unit 1 First Ten-Year Interval inservice Inspection Program RELIEF REQUEST NO. RR-22, Revision 1 i
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LGS, Unit 1 Docket No. 50-352 ISI Program Page 1 of 2 REUEF REQUEST NO. RR-22 Revision 1 1.
IDENTIFICATION OF COMPONENTS
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All Class 1,2, and 3 Pressure Retaining Components subject to Hydrostatic Testing per IWA-4400 and IWA-5000.
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CODE REQUIREMENTS FROM WHICH REUEF IS REQUESTED ASME Code,Section XI,1906 Edition, IWA-4400 requires an elevated pressure hydrostatic test to be performed after repairs by welding, or the installation of replacement items by welding, on the pressure retalning boundary of Class 1,2, and 3 components.
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BASIS FOR REUEF i
Elevated pressure hydrostatic tests are difficult to perform and often represent a true hardship. Some of the difficulties associated with elevated pressure testing include the following:
Hydrostatic testing often requires complicated or abnormal valve line-ups in -
order to propedy vent, fill, and Isolate the component requiring testing.
Relief valves with setpoints lower than the hydrostatic test pressure must be gagged, or removed and blind flanged. The removal and flanging process requires the draining and refilling of the system.
Valves that are not normally used for isolation (normally open pump discharge valves), require time consuming seat maintenance in order to aliow for pressurization.
The radiation exposure required to perform a hydrostatic pressure test is high due to the large amount of time required to prepare the system for testing (install relief valve gags, perform appropriate valve line-ups, etc.).
The difficulties encountered in performing a hydrostatic pressure test are prohibitive when weighed against the benefits. Industry experience shows that most through wall leakage is detected during system operation as opposed to during elevated pressure tests such as 10-year hydrostatic tests.
Little benefit is gained from the added challenge to the piping system provided by an elevated pressure test, when compared to an operational test, especially wtm one considers that the piping stress experienced during a hydrostatic test does not include the significant stresses associated with the thermal growth and dynamic loading associated with design basis.
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.. LGS, Unt 1 Docket No. 50-352 ISI Program 1.
Page 2 d 2 RELIEF REQUEST NO. RR-2*
Revision 1 (Continued)
IV.
ALTERNATE PROVISIONS As an altemate to the existing ASME Code,Section XI requirements, LGS 1 proposes the following NDE shall be performed in accordance wkh the methods and acceptance criteria d the applicable Subsection d the Construction Code (e.g. ASME Section Ill).
i When #wiikig repairs by welding, or the installation d replacement i
kems by welding, on the pressure retaining boundary of Class 3 components, NDE shall be performed in accordance with the methods and acceptance criteria d the Construction Code (e.g. ASME Section Ill), in addition, when an examination is used in accordance with the.
Construction Code for a butt joint, an additional examination (Magnetic Particle or Liquid Penetrant) (MT/PT)) chall be performed on the root pass layer. This provision does not apply to Class 1 and 2 coinpor,esits, i
since examinations will be performed in accordance with Code requirements.
- i Prior to or immediately upon retum to service, a visual examination (VT 2) shall.
be performed in conjunction with a system leakage test (functional or inservice),
in accordance with paragraph IWA-5000, with no hold times.
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Umerick Generating Station, Unit 2 First Ten-Year interval Inservice inspection Program j
s RELIEF REQUEST NO. RR-16, Revision 1 ~
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LGS, Unit 2 Docket No. 50-353 ISI Program Page 1 of 2 l
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REUEF REQUEST NO. RR Revision 1
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IDENTIFICATION OF COMPONENTS l
All Class' 1,2, and 3 Pressure Retaining Components subject to *@rostatic Testing por j
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CODE REQUIREMENTS FROM WHICH REUEF IS REQUESTED
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ASME Code,Section XI,1986 Edition, IWA 4400 requires an elevated pressure j
hydrostatic test to be performed after repairs by welding, or the installation d i
replacement items by welding, on the pressure retaining boundary of Class 1,2, and 3 l
components j
1 111.
BASIS FOR REUEF Elevated pressure hydrostatic tests are difficult to perform and often represent a true hardship. Some of the difficulties associated with elevated pressure testing include the following j
Hydrostatic testing often requires complicated or abnormal valve line-ups in order to properly vent, flu, and isolate the component requiring testing.
Relief valves with setpoints lower than the hydrostatic test pressure must be gagged, or removed and blind flanged. The removal and flanging process requires the draining and refiling of the system.
i Valves that are not normany used for isolation (normally open pump discharge j
valves) These valves require time contuming seat maintenance in order to allow for pressurization.
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The radiation exposure exposure required to perform a hydrostatic pressure test is high due to the large amount of time required to prepare the system for i
testing (install relief valve gags, perform appropralte valve line-ups, etc.).
i The difficulties encountered in performing a hydrostatic pressure test are prohibitive j
when weighed against the benefits. Industry experience shows that most through waN leakage is detected during system operation as opposed to during elevated pressure tests such as 10-year hydrostatic tests.
Little benefit is gained from the added challenge to the piping system 'provided by an elevated pressure test, when compared to an operational test, especiauy when one l
considers that the piping stress experienced during a hydrostatic test does not include j
the significant stresses associated with the thermal growth and dynamic loading j
associated with design basis.
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LGS, Unit 2 Docket No. 50-353 ISI Program Page 2 of 2 REUEF REQUEST NO. RR-16 Revision 1 (Continued)
IV.
ALTERNATE PROVISIONS As an alternate to the existing ASME Code,Section XI requirements, LGS 2 proposes the following NDE shall be performed in accordance with the methods and acceptance crteria of the applicable Subsection d the Construction Code (e.g. ASME Section Ill).
When p Twining repairs by welding, or the installation of replacement hems by welding, on the pressure retaining boundary of Class 3 components, NDE shall be performed in accordance with the methods and acceptance criteria of the Construction Code (e.g. ASME Section
!!!). In addition, when an examination is used in accordance with the Construction Code for a butt joint, an additional examination (Liquid Penetrant or Magnetic Particle (PT/MT)) shall be perisined on the root pass layer. This provision does not apply to Class 1 and 2 components, since examinations will be performed in accordance with Code requirements.
Prior to or immediately upon retum to service, a visual examination (VT-2) shall be performed in conjunction with a system leakage test (functional or Inservice),
in accordance with paragraph IWA-5000, with no hold times.
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