ML20073H438
| ML20073H438 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 09/27/1994 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9410050245 | |
| Download: ML20073H438 (11) | |
Text
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station support Dep rtment 10CFR50.55a(g)(5)(iii) 4 PECO ENERGY
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a 965 Chesterbrook Boulevard Wayne. PA 19087 5691 1
i September 27,1994 Docket Nos. 50452 50453
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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 Relief Requests for First Ten Year Interval inservice Inspection Programs for Performance of System Pressure Tests Gentlemen Attached for review and approval are three (3) Relief Requests 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) Bouer and Pressure Vessel (B&PV)
Code,1986 Edition, regarding pressure tests for various Class 1,2, and 3 systems and pressure retalning components, which include olping, pumps, and valves. Two (2) of the three (3) Relief Requests apply to the LGS Unit 1 IS! Program (i.e., Specification NE-42), whue the third Relief Request pertains to the LGS Unit 2 ISI Program (i.e., Specification NE-27). A brief description of each Relief Request is provided below.
Unit 1 Relief Requests Relief Request No. RR-12, Revision 1 This Relief Request requests the use of Code Case N-498-1, " Alternate Rules for 10-Year Hydrostatic Pressure Testing for Class 1,2, and 3 Systems," which been approved by ASME, but has not yet been endorsed by the NRC.
Relief Request No. RR-22 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 j
pressure tests.
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r September 27,1994 Page 2 Unit 2 Relief Request Relief Request No. RR-16 This Relief Request is identical to Relief Request No. RR-22 described above for Unit 1, which requests relief from the ASME Code requirements specified in Section XI, Subsection IWA-4400, concoming elevated pressure hydrostatic testing in accordance with the requirements IWA-5000, after repairs by welding, 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 the same altamate testing provisions as described above for Relief Request No.
RR-22.
The specific detals and justification for relief are provided in the attached Relief Requests. We are requesting that the NRC review the attached Relief Requests for the LGS, Units 1 and 2, ISI Programs, and grant the necessary relief by Jurm 30,1995.
If you have any questions or require additional Information, please do not hesitate to contact us.
Very truly yours, ha.
,p.
G. A. Hunger, Jr.
Director - Licensing Attachments cc:
T. T. Martin, Administrator, USNRC, Region I (w/ attachments)
N. S. Perry, USNRC Senior Resident inspector, LGS (w/ attachments)
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i Limerick Generating Station, Unit 1 First Ten-Year interval inservice inspection Program RELIEF REQUEST NO. RR-12, Rev.1 l
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Docket No. 50-352 Page 1 of 2 Limerick Generating Station, Unit 1 REUEF REQUEST NO. RR-12 Revision 1 i
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SCOPE This relief request is applicable to those ASME Code Case (s) adopted for use in this ISI Program which have not been specificaHy endorsed for use by the USNRC in Regulatory Guide 1.147.
i 11.
DISCUSSION i
Code Cases are periodically published by the ASME for the purpose of either clarifying the intent of Code rules or for providing rules and regulations for circumstances which are not currently i
covered by existing Code rules but need to be addressed in a timely manner. Use of these notwnandatory Code Cases for inservice inspection is subject to USNRC acceptance of the Code Case (s); Regulatory Guide 1.147 lists those Codes Cases that have been reviewed by the NRC and are generally acceptable for implementation in an ISI Program. Other Code Cases may be used provided specific authorization is requested pursuant to 10CFR50.55a.
The purpose of this relief request is to request authorization of the adoption of specific Code Cases for implementation in the LGS 1 ISI Program.
111.
CODE CASE (S) REQUIRING AUTHORIZATION j
The following Code Case requires specific authorization for use in the LGS 1 ISI Program:
A.
N-496-1; Attemate Rules for 10-Year Hydrostatic Pressure Testing for Class 1,2, and 3 Systems.
Adoption of this Code Case will elimirwe the need for the performance of the Class 1,2, and 3 end of First interval (EOI) Hydrostatic Test, as required by ASME Boiler and Pressure Vessel (B&PV) Code,Section XI, thereby, reducing the amount of personnel radiation exposure received during the performance of the Class 1,2, and 3 hydrostatic test.
IV.
ALTERNATE PROVISIONS The altemative rules of the Code Case in lit above shall be implemented in the LGS 1 1S1 Program for the First inservice inspection interval.
As an allemative, a Class 1 system leakage test shall be conducted at or near the end of the inspection interval. The boundary subject to test pressurization during the system leakage test shaN extend to aN Class 1 pressure retaining components within the system boundary. In addition, a Class 2 and 3 system pressure test wul be conducted at or near the end of the interval. The boundary subject to test pressurization during the system pressure test wHl extend to all Class 2 and 3 compci, eats required to operate or support the safety system function up to and including the first normally closed valve, including a safety or relief valve or valve capable of automatic closure when
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the safety function is required.
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Docker No. 50-352 Page 2 d 2 REUEF REQUEST NO. RR-12 Revision 1 (Continued)
V.
BASIS FOR RELIEF l
The Code Casa diasmaari in Section 111 above represents technically acceptable altt:rnative rules to ASME Section XI Code requirememts. The fact that this Code Case has not boon adorsed by the NRC and referenced in Regulatory Guide 1.147 in no way detracts from its technical adequacy since the major reason for its omission is the timing d its publication with respect to the most recent revision d the Regulatory Guide. That is, the subject Code Case is relatively recent and it is expected that it will be accepted in a subsequent revision of the Regulatory Guide.
Adoption d this altamative rule provides an acceptable level d quality and safety sind does not compromise the adequacy d the LGS 1 ISI Program in meeting the intent d ASME Section XI.
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l Limerick Generating Station, Unit 1 First Ten-Year interval inservice inspection Program RELIEF REQUEST NO. RR-22 l
Docket No. 50-352 I
Page 1 of 2 Umerick Generating Station, Unit 1 REUEF REQUEST NO. RR-22 Revision 0 1.
IDENTIFICATION OF COMPONENTS All Class 1,2, and 3 Pressure Retaining Components subject to Hydrostatic Testing per IWA Service Water (ESW), Feedwater (FW), High Pressure Coola Removal Service Water (RHRSW), Reactor Recirculation (RR), Reactor Pressure Vessel Reactor Core isolation Cooling (RCIC), Reactor Water Clean Up (RWCU), and Residual Hea Removal (RHR).
II.
CODE REOUIREMENTS FROM WHICH RELIEF IS REQUESTED ASME Code,Section XI,1986 Edition, IWA-4400 requires an elevated pressure hydrostatic te be performed in accordance with IWA-5000 after repairs by welding, or the installation of replacement items by welding, on the pressure retalning boundary of Class 1,2, and 3 comp Ill.
BASIS FOR RELIEF Some of the difficulties associated with elevated pressure te Hydrostatic testing often requires complicated or abnormal va!ve line-ups in order to properly vent, fill, and isolate the component requiring testing.
Rollef valves with setpoints lower than the hydrostatic test pressure must be gagged, e
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 val e
require time consuming seat maintenance in order to allow for pressurization.
The radiation exposure required to perform a hydrostatic pressure test is high due to the e
large araount of time required to prepare the system for testing (install relief valve ga perform appropriate valve line-ups, etc.).
The difficuttles encountered in performing a hydrostatic pressure test are prohibitive w i
against the benefits. Industry experience shows that most through wallleakage is detecte system operation as opposed to during elevated pressure tests such as 10-year hydrostatic tests.
l Uttle benefit is gained from the added challenge to the piping system provided by an eleva pressure test, when compared to an operational test, especially when one considers that the stress experienced during a hydrostatic test does not include the significant stresses associate the thermal growth and dynamic loading associated with design basis.
1 Docket No. 50-352 Page 2 of 2 RELIEF REQUEST NO. RR-22 Revision 0 (Continued)
I IV.
ALTERNATE PROVISIONS I
As an alternate to the existing ASME Code,Section XI requirements, LGS 1 proposes the following:
NDE shall be performed in accordance with the methods and acceptance criteria of the apolicable Subsection of the Construction Code (e.g. ASME Section lil).
o When performing repairs by welding, or the installation of replacement items by welding, on the pressure retaining boundary of Class 1,2, and 3 components, NDE shall be performed in accordance with the methods and acceptance criteria of the Construction Code (e.g. ASME Section I!!). In addition, when an examiration is used in accordance with the Construction Code for a butt joint, an additional examination (Magnetic Particle or Liquid Penetrant, MT/PT) shall be performed 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.
e Prior to or immediately upon return 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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O Limerick Generating Station, Unit 2 First Ten-Year Interval inservice inspection Program RELIEF REQUEST NO. RR-16 l
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Docket No. 50-353 Page 1 of 2 Limerick Generating Station, Unit 2 RELIEF REQUEST NO. RR-16 Revision 0 i.
IDENTIFICATION OF COMPONENTS All Class 1,2, and 3 Pressure Retaining Components subject to Hydrostatic Testing per IWA-4400 1
and IWA-5000. This Relief Request applies to the following systems: Mala Steam (MS), Emergency Service Water (ESW), Feedwater (FW), High Pressure Coolant injection (HPCI), Residual Heat Removal Service Water (RHRSW), Reactor Recirculation (RR), Reactor Pressure Vessel (RPV) Drain, Reactor Core isolation Cooling (RCIC), Reactor Water Clean Up (RWCU), and Residual Heat Removal (RHR).
II.
CODE REQUIREMENTS FROM WHICH REllEF IS REQUESTED ASME Code,Section XI,1986 Edition, lWA-4400 requires an elevated pressure hydrostatic test to be performed in accordance with IWA-5000 after repairs by welding, or the installation of replacement items by welding, on the pressure retaining boundary of Class 1,2, and 3 components.
111.
BASIS FOR RELIEF Elevated pressure hydrostatic tests are difficult to perform and often represent a true hardship.
Some of the difficuttles associated with elevated pressure testing include the following:
f Hydrostatic testing often requires complicated or abnormal valve line-ups in order to e
properly vent, fill, and isolate the component requiring testing.
e 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)
These valves reculre tLmo consuming seat maintenance in order to allow for pressurization.
e The radiatica exposure required to perform a hydrostatic pressure test is high due to the large c~.ount of time required to prepare the system for testing (install relief vafve 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, especia!!y when one considers that the piping stress expwienced 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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.c Docket No. 50-353 Page 2 of 2 RELIEF REQUEST NO. RR-16 Revision 0 (Continued)
IV.
ALTERNATE PROVISIONS As an alternate to the existing ASME Code,Section XI requirements, LGS 2 proposes the following:
e NDE shall be performed in accordance with the methods and acceptance criteria of the applicable Subsection of the Construction Code (e.g. ASME Section 111).
When performing repairs by welding, or the installation of replacement items by welding, on the pressure retalning boundary of Class 3 components, NOE shall be performed in accordance with the methods and acceptance criteria of the Construction Code (e.g. ASME Section 111). In addition, when an examination is used in accordance with the Construction Code for a butt joint, an additional examination (Magnetic Particle or Uquid Penetrant, MT/PT) shall be performed 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.
e Prior to or immediately upon return 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.