ML060950269
| ML060950269 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee  |
| 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 | |
| ML060950189 | List:
|
| References | |
| %dam200611, TAC MC9668 | |
| Download: ML060950269 (8) | |
Text
AUDIT WORKSHEET GALL REPORT AMP PLANT: ______________________________
LRA AMP: __________________________ REVIEWER: ______________________
GALL AMP: XI.E6, Electrical Cable Connections Not Subject to 10 CFR DATE: __________________________
50.49 Environmental Qualification Requirements Program Auditable GALL Criteria Documentation of Audit Finding Element Program A. Cable connections are used to connect cable conductors to Consistent with GALL AMP: Yes No Description other cables or electrical devices. Connections associated with Document(s) used to confirm Criteria:
cables within the scope of license renewal are part of this program. The most common types of connections used in nuclear power plants are splices (butt or bolted), crimp-type ring lugs, connectors, and terminal blocks. Most connections involve Comment:
insulating material and metallic parts. This aging management program for electrical cable connections (metallic parts) account for the following aging stressors: thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, and oxidation.
B. GALL XI.E1, Electrical Cables and Connections Not Subject Consistent with GALL AMP: Yes No to 10 CFR 50.49 Environmental Qualification Requirements, Document(s) used to confirm Criteria:
manages the aging of insulating material but not the metallic parts of the electrical connections. 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 Comment:
thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, and oxidation on the metallic parts of cable connections.
C. Circuits exposed to appreciable ohmic or ambient heating Consistent with GALL AMP: Yes No during operation may experience loosening related to repeated Document(s) used to confirm Criteria:
cycling of connected loads or of the ambient temperature XI.E6 Electrical Cable Connections Not Subject To 10 CFR 50.49 EQ Requirements 1
Program Auditable GALL Criteria Documentation of Audit Finding Element environment. Different materials used in various cable system components can produce situations where stresses existing between these components change with repeated thermal Comment:
cycling. For example, under loaded conditions, appreciable ohmic heating may raise the temperature of a compression termination and cable conductor well above the ambient temperature, thereby causing thermal expansion of both components. Different thermal expansion coefficients may alter mechanical stresses between the components so that the termination may tighten on the conductor. When the load or current is reduced, the affected components cool and contract.
Repeated cycling in this fashion can produce loosening of the termination under ambient conditions, and may lead to high electrical resistance joints or eventual separation to compression-type terminations. Threaded connectors, splices, and terminal blocks may loosen if subjected to significant thermally induced stress and cycling.
D. Cable connections within the scope of license renewal should Consistent with GALL AMP: Yes No be tested to provide an indication of the integrity of the cable Document(s) used to confirm Criteria:
connections. The specific type of test performed will be determined prior to the initial test, and is to be a proven test for detecting loose connections, such as thermography, contact resistance testing, or other appropriate testing justified in the Comment:
application. This program, as described, can be thought of as a sampling program. The following factors are considered for sampling: application (high, medium and low voltage), circuit loading, and location (high temperature, high humidity, vibration, etc.). The technical basis for the sample selections is documented. If an unacceptable condition or situation is identified in the selected sample, a determination is made as to whether the same condition or situation is applicable to other connections not tested.
E. SAND 96-0344, Aging Management Guidelines for Electrical Consistent with GALL AMP: Yes No Cable and Terminations, indicated loose terminations were Document(s) used to confirm Criteria:
XI.E6 Electrical Cable Connections Not Subject To 10 CFR 50.49 EQ Requirements 2
Program Auditable GALL Criteria Documentation of Audit Finding Element identified by several plants. 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 the connections are not subject to the Comment:
environmental qualification requirements of 10 CFR 50.49, an aging management program is required to manage the aging effects. This program will ensure that electrical cable connections will perform their intended function for the period of extended operation.
- 1. Scope of A. Connections associated with cables in scope of license Consistent with GALL AMP: Yes No Program renewal are part of this program, regardless of their association Document(s) used to confirm Criteria:
with active or passive components.
Comment
- 2. Preventive A. No actions are taken as part of this program to prevent or Consistent with GALL AMP: Yes No Actions mitigate aging degradation. Document(s) used to confirm Criteria:
Comment:
- 3. Parameters A. This program will focus on the metallic parts of the Consistent with GALL AMP: Yes No Monitored/ connection. The monitoring includes loosening of bolted Document(s) used to confirm Criteria:
Inspected connections due to thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, and oxidation. A representative sample of electrical cable connections is tested. The following factors are to be considered Comment:
for sampling: application (high, medium and low voltage), circuit loading, and location (high temperature, high humidity, vibration, etc.). The technical basis for the sample selected is to be documented.
XI.E6 Electrical Cable Connections Not Subject To 10 CFR 50.49 EQ Requirements 3
Program Auditable GALL Criteria Documentation of Audit Finding Element
- 4. Detection A. Electrical connections within the scope of license renewal will Consistent with GALL AMP: Yes No of Aging be tested at least once every 10 years. Testing may include Document(s) used to confirm Criteria:
Effects thermography, contact resistance testing, or other appropriate testing methods. This is an adequate period to preclude failures of the electrical connections since experience has shown that aging degradation is a slow process. A 10-year testing interval Comment:
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.
- 5. Monitoring A. Trending actions are not included as part of this program Consistent with GALL AMP: Yes No and Trending because the ability to trend test results is dependent on the Document(s) used to confirm Criteria:
specific type of test chosen. However, test results that are trendable provide additional information on the rate of degradation.
Comment:
- 6. A. The acceptance criteria for each test are defined by the Consistent with GALL AMP: Yes No Acceptance specific type of test performed and the specific type of cable Document(s) used to confirm Criteria:
Criteria connections tested.
Comment:
- 7. Corrective A. An engineering evaluation is performed when the test Consistent with GALL AMP: Yes No Actions acceptance criteria are not met in order to ensure that the Document(s) used to confirm Criteria:
intended functions of the cable connections 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 Comment:
concern, the potential root causes for not meeting the test acceptance criteria, the corrective action necessary, and the likelihood of recurrence. When an unacceptable condition or situation is identified, a determination is made on whether the same condition or situation is applicable to other in-scope cable XI.E6 Electrical Cable Connections Not Subject To 10 CFR 50.49 EQ Requirements 4
Program Auditable GALL Criteria Documentation of Audit Finding Element connections not tested. 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.
- 8. A. As discussed in the appendix to this report, the staff finds the Consistent with GALL AMP: Yes No Confirmation requirements of 10 CFR Part 50, Appendix B, acceptable to Document(s) used to confirm Criteria:
Process address the confirmation process.
Comment:
- 9. A. As discussed in the appendix to this report, the staff finds the Consistent with GALL AMP: Yes No Administrative requirements of 10 CFR Part 50, Appendix B, acceptable to Document(s) used to confirm Criteria:
Controls address the administrative controls.
Comment:
- 10. Operating A. Operating experience has shown that loosening of Consistent with GALL AMP: Yes No Experience connections and corrosion of connections are aging mechanisms Document(s) used to confirm Criteria:
that, if left unmanaged, could lead to a loss of electrical continuity and potential arcing or fire.
Comment:
XI.E6 Electrical Cable Connections Not Subject To 10 CFR 50.49 EQ Requirements 5
EXCEPTIONS Item Program Elements LRA Exception Description Basis for Accepting Exception Documents Reviewed Number (Identifier, Para.# and/or Page #)
1.
2.
ENHANCEMENTS Item Program Elements LRA Enhancement Description Basis for Accepting Enhancement Documents Reviewed Number (Identifier, Para.# and/or Page #)
1.
2.
DOCUMENT REVIEWED DURING AUDIT Document Number Identifier (number) Title Revision and/or Date 1.
2.
3.
4.
XI.E6 Electrical Cable Connections Not Subject To 10 CFR 50.49 EQ Requirements 6