ML20080B255
| ML20080B255 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 11/22/1994 |
| From: | Benes G COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9411300204 | |
| Download: ML20080B255 (3) | |
Text
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November 22,1994 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555
Subject:
LaSalle County Nuclear Power Station Units 1 and 2 Inservice Inspection Program Submittal of Relief Request RI-31 NRC Docket Nos. 50-373 and 50-374 LaSalle County Station performs pressure tests in accordance with ASME Section XI,1980 Edition, Winter 1980 addenda. ASME Section XI, IWD-5223 requires Class 3 systems be subjected to elevated pressure hydrostatic tests _
Relief Request RI-31 requests to change this to functional or in-service tests.
Relief Request RI-31 is based on the ASME/ National Board approval of Code Case N-498-1, " Alternative Rules for 10-Year System Hydrostatic Testing for Class 1,2, and 3 Systems,Section XI Division 1, Approved May 11, 1994" Relief Request RI-31 is applicable to both LaSalle Units 1 and 2, and it is requested that the relief extend through the remainder of the first 10 year Inspection Interval.
Comed requests approval of this relief request as soon as possible to support the upcoming Unit 2 sixth refueling outage which is scheduled to begin on February 17,1995.
Please contact this ofIice should further information be required.
Very truly yours,
&SBed Ga G. Benes Nuclear Licensing Administrator Attachment ec:
J. B. Martin, Regional Administrator - RIII P G. Brochman, Senior Resident Inspector - NRC, LaSalle W. D. Reckley, Project Manager, NRR OfTice Of Nuclear Facility Safety - IDNS t
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RELIEF REQUEST NUMBER: RI-31 COMPONENT IDENTIFICATION Code Class:
3 Referer.ce:
Table IWD-2500-1, and IWD-5223(a)
Examination Category:
D-A, D-B, and D3.10 Item Numbers:
D.1.10, D2.10, and D3.10
==
Description:==
Alternate Testing of Class 3 Systems In Lieu of Ten-Year Hydrostatic Pressure Testing Component Numbers:
Various CODE ILEOUIREMENT ASME Section XI, Table IWD-2500-1 requires Class 3 pressure retaining components be exposed to VT-2 examinations while the systems are subjected to elevated pressure hydrostatic tests, at or near the end of each inspection interval.
ASME Section X.I, IWD 5223(a) states that the system hydrostatic pressure shall be at least 1.10 times the system pressure (Psv) for systems with a design temperature of 200 'F or less. It also states that the system pressure (Psv) shall be the lowest pressure setting among the number of safety or relief valves provided for over-pressure protection within the boundary to be tested or design pressure (Pd) if over-pressure protection is not provided.
IMSIS FOILRELIEF Elevated pressure 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 lineups in order to properly fill, vent and isolate the components requiring testing.
Relief valves with set-points lower than the hydrostatic test pressure must be gagged or removed and have blind flanges installed. This process requires draining and refilling the system.
Valves that are not normally used for isolation (e.g.,normally open pump discharge valves) are eften required to provide pressure isolation for an elevated pressure hydrostatic test. These valves frequently require time consuming seat maintenance in order to allow for pressurization.
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l The radiation exposure required to perform a hydrostatic pressure test is high (in comparison to an operational pressure test) due to the large amount of time required to prepare the system for testing.(i.e. installing relief valve gags, installing spool pieces, installing blind flanges,
- performing appropriate valve lineups, etc) i The difficulties encountered in performing a hydrostatic pressure test are l
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 the ten-year hydrostatic tests.
.I Little benefit is gained from the added challenge to the piping system provided by-an elevated pressure hydrostatic test (when compared to an operational pressure test). This becomes more obvious when one considers that, the piping stress l
experienced during a hydrostatic test does not include significant stresses associated with the thermal growth and dynamic loading associated with design basis events.
These arguments are also supported by the ASME/ National Board approval of Code Case N-498-1 " Alternative Rules for 10-Year System Hydrostatic Testing for l
Class 1,2, and 3 Systems,Section XI Division 1, Approved May 11,1994". This relief request is based on that code case approval.
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-Based on the above, LaSalle County Station requests relief from the ASME 1
Section XI requirements for performing the ten-year elevated pressure hydrostatic tests on class 3 systems.
t PROPOSED ALTERNATE EXAMINATIOR l
i A VT-2 examination will be performed during either a system functional test or during a system inservice test, in accordance with the requirements ofIWA--
5213(b) and (c) respectively, at or near the end of the inspection interval.
I APPLICABLE TIME PERIOD Reliefis requested for the first ten-year interval of the System Pressure Testing l
Program at LaSalle county Station Unit 1 and 2.
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