ML060950262

GALL AMP: XI.E5, Fuse Holder (Audit Worksheet GALL Report AMP)

ML060950262
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	03/22/2006
From:	Morgan M NRC/NRR/ADRO/DLR/RLRC
To:	Office of Nuclear Reactor Regulation
morgan M NRR/NRC/DLR/RLRC, 415-2232
Shared Package
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References
%dam200611, TAC MC9668
Download: ML060950262 (5)

Text

XI.E5 Fuse Holders 1

AUDIT WORKSHEET GALL REPORT AMP PLANT: ______________________________

LRA AMP: __________________________

REVIEWER: ______________________

GALL AMP: XI.E5, Fuse Holders DATE: __________________________

Program Element Auditable GALL Criteria Documentation of Audit Finding Program Description A. Fuse holders (fuse blocks) are classified as a specialized type of terminal block because of the similarity in fuse holder design and construction to that of a terminal block. Fuse holders are typically constructed of blocks of rigid insulating material, such as phenolic resins. Metallic clamps (clips) are attached to the blocks to hold each end of the fuse. The clamps, which are typically made of copper, can be spring-loaded clips that allow the fuse ferrules or blades to slip in, or they can be bolt lugs, to which the fuse ends are bolted.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

B. GALL XI.E1, Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, will manage the aging of insulating material but not the metallic clamps of the fuse holders. The aging management program for fuse holders (metallic clamps) needs to account for the following aging stressors, if applicable: fatigue, mechanical stress, vibration, chemical contamination, and corrosion. GALL XI.E1 is based on only a visual inspection of accessible cables and connections. Visual inspection is not sufficient to detect the aging effects from fatigue, mechanical stress, vibration, or corrosion on the metallic clamps of the fuse holder.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

C. Fuse holders that are within the scope of license renewal should be tested to provide an indication of the condition of the metallic clamps of the fuse holders. The specific type of test performed will be determined prior to the initial test, and is to be Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

XI.E5 Fuse Holders 2

Program Element Auditable GALL Criteria Documentation of Audit Finding a proven test for detecting deterioration of metallic clamps of the fuse holders, such as thermography, contact resistance testing, or other appropriate testing justified in the application.

Comment:

D. As stated in NUREG-1760, Aging Assessment of Safety-Related Fuses Used in Low and Medium-Voltage Applications in Nuclear Power Plants, fuse holders experience a number of age-related failures. The major concern is that failures of a deteriorated cable system (cables, connections including fuse holders, and penetrations) might be induced during accident conditions. Since they are not subject to the environmental qualification requirements of 10 CFR 50.49, an aging management program is required to manage the aging effects.

This program will ensure that fuse holders will perform their intended function for the period of extended operation.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

1. Scope of Program A. This program applies to fuse holders located outside of active devices and are considered susceptible to aging effects. Fuse holders inside an active device (e.g., switchgears, power supplies, power inverters, battery chargers, and circuit boards) are not within the scope of this program.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment

2. Preventive Actions A. No actions are taken as part of this program to prevent or mitigate aging degradation.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

3. Parameters Monitored/

Inspected A. This program will focus on the metallic clamp portion of the fuse holder. The monitoring includes thermal fatigue in the form of high resistance caused by ohmic heating, thermal cycling or electrical transients, mechanical fatigue caused by frequent removal/replacement of the fuse or vibration, chemical contamination, corrosion, and oxidation.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

XI.E5 Fuse Holders 3

Program Element Auditable GALL Criteria Documentation of Audit Finding

4. Detection of Aging Effects A. Fuse holders within the scope of license renewal will be tested at least once every 10 years. Testing may include thermography, contact resistance testing, or other appropriate testing methods. This is an adequate period to preclude failures of the fuse holders since experience has shown that aging degradation is a slow process. A 10-year testing interval will provide two data points during a 20-year period, which can be used to characterize the degradation rate. The first tests for license renewal are to be completed before the period of extended operation.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

5. Monitoring and Trending A. Trending actions are not included as part of this program because the ability to trend test results is dependent on the specific type of test chosen. However, results that are trendable provide additional information on the rate of degradation.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

6. Acceptance Criteria A. The acceptance criteria for each test are defined by the specific type of test performed and the specific type of fuse holder tested.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

7. Corrective Actions A. An engineering evaluation is performed when the test acceptance criteria are not met in order to ensure that the intended functions of the fuse holders can be maintained consistent with the current licensing basis. Such an evaluation is to consider the significance of the test results, the operability of the component, the reportability of the event, the extent of the concern, the potential root causes for not meeting the test acceptance criteria, the corrective action necessary, and the likelihood of recurrence. As discussed in the appendix to this report, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

XI.E5 Fuse Holders 4

Program Element Auditable GALL Criteria Documentation of Audit Finding

8.

Confirmation Process A. As discussed in the appendix to this report, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

9.

Administrative Controls A. As discussed in the appendix to this report, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

10. Operating Experience A. Operating experience has shown that loosening of fuse holders and corrosion of fuse clips are aging mechanisms that, if left unmanaged, can lead to a loss of electrical continuity function.

Consistent with GALL AMP:

Yes No Document(s) used to confirm Criteria:

Comment:

XI.E5 Fuse Holders 5

EXCEPTIONS Item Number Program Elements LRA Exception Description Basis for Accepting Exception Documents Reviewed (Identifier, Para.# and/or Page #)

1.

2.

ENHANCEMENTS Item Number Program Elements LRA Enhancement Description Basis for Accepting Enhancement Documents Reviewed (Identifier, Para.# and/or Page #)

1.

2.

DOCUMENT REVIEWED DURING AUDIT Document Number Identifier (number)

Title Revision and/or Date

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3.

4.

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