ML050190295
| ML050190295 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/10/2005 |
| From: | O'Connor T Constellation Energy Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMPIL 1912, TAC MC3272, TAC MC3273 | |
| Download: ML050190295 (23) | |
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Constellation Energy' Nine Mile Point Nuclear Station RO. Box 63 Lycoming, New York 13093 January 10, 2005 NMPIL 1912 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Nine Mile Point Units 1 and 2 Docket Nos. 50-220 and 50410 Facility Operating License Nos. DPR-63 and NPF-69 License Renewal Application - Responses to NRC Requests for Additional Information Regarding Aging Management of Electrical and Instrumentation and Control Systems (TAC Nos. MC3272 and MC3273)
Gentlemen:
By letter dated May 26, 2004, Nine Mile Point Nuclear Station, LLC (NMPNS) submitted an application to renew the operating licenses for Nine Mile Point Units I and 2.
In a letter dated December 10, 2004, the NRC requested additional information regarding aging management of electrical and instrumentation and control systems, as described in Section 3.6 of the License Renewal Application. The NMPNS responses to these requests for additional information are provided in Attachments 1 through 4. This letter contains no new regulatory commitments.
If you have any questions about this submittal, please contact Peter Mazzaferro, NMPNS License Renewal Project Manager, at (315) 349-1019.
Vytruy mo
'Connor Plant e eral Manager TJOIDEV/jm 4X(P17
Page 2 NMUP1L 1912 STATE OF NEW YORK
- TO WIT:
COUNTY OF OSWEGO I, Timothy J. O'Connor, being duly sworn, state that I am Nine Mile Point Plant General Manager, and that I am duly authorized to execute and file this supplemental information on behalf of Nine Mile Point Nuclear Station, LLC. To the best of my knowledge and belief, the statements contained in this submittal are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon inform ion provided by other Nine Mile Point employees and/or consultants. Such information h I/ een revie d in accordance with company practice and I believe it to be reliable.
Subscribed and sworn before me, a Notary Public in and for the State ew York and County of Oswego,this lo" dayof cArV 2005.
WITNESS my Hand and Notarial Seal:
SUSAN L. SABINE Notary Public "Notary Public, State of New Yorke Qualified in Oswego County
/
My Commission Expires:
Registration No. 01SA6031903 i/
05 Commission Expires 10-12-c;>j Date Attachments:
- 1. Responses to NRC Requests for Additional Information (RAI) Regarding Aging Management of Electrical and Instrumentation and Control Systems, as Described in Section 3.6 of the License Renewal Application
- 2. Revisions to LRA Tables 3.6.2.C-2, 3.6.2.C-3, and 3.6.2.C-4
- 3. Revisions to LRA Sections Al. 1.27 and A2. 1.27
- 4. Revisions to LRA Section B2.1.34 cc:
Mr. S. J. Collins, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector Mr. P. S. Tam, Senior Project Manager, NRR Mr. N. B. Le, License Renewal Project Manager, NRR Mr. J. P. Spath, NYSERDA
ATTACHMENT 1 Nine Mile Point Nuclear Station Responses to NRC Requests for Additional Information (RAT)
Rezardin2 Agin2 Mananement of Electrical and Instrumentation and Control Systems, as Described in Section 3.6 of the License Renewal Application This attachment provides Nine Mile Point Nuclear Station, LLC (NMPNS) responses to the requests for additional information contained in the NRC letter dated December 10, 2004, regarding aging management of electrical and instrumentation and control systems. Each NRC RAI is repeated, followed by the NMPNS response. Revisions to the License Renewal Application (LRA) are described where appropriate. The revisions are highlighted by shading unless otherwise noted.
RAI 3.6.2.C-l LRA Table 3.6.2. C-1 conveys that cables, connectors, splices, and terminal blocks are constnrcted of only various organic polymers. Table 3.6.2. C-l from the LR2A supplemental letter dated October 29, 2004, conveys that only the i,,szlatio,, of cables, connectors, splices, and terminal blocks are subject to an aging management review (AMR). Cables, connectors, splices, and terminal block connecting points are also constnrcted of conductive material that is also suibject to an AMR For cables, connectors, splices, and terminal block connecting points that may perform safety-relatedfunction as per 10 CFR 54.21 (a)(1) requirement, please identify all materialsfrom which they are constnrcted. Please also provide additional information regarding the applicable AMR resultsfor these identif ed materials.
Response
LRA Table 3.6.2.C-1 is intended to encompass the conductive and insulating materials for cables, connectors, splices, terminal blocks, and fuse holders at NMPNS. The revised table submitted in the NMPNS LRA supplemental letter NMP1L 1880 dated October 29, 2004, was in response to questions raised during the aging management programs audit and to illustrate consistency with NUREG-1801, Table VI.A. The Non-EQ Electrical Cables and Connections Program credited in LRA Table 3.6.2.C-1 is a new program that will be consistent, upon implementation, with NUREG-1801,Section XI.E1, "Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualifications Requirements." Included in this program is the inspection of the accessible portions of the conductive surfaces of the listed components as Page 1 of 12
well as the evaluation and resolution of degraded conditions. Therefore, while not explicitly listed, the conductive and insulating materials for cables, connectors, splices, and terminal blocks are subject to an aging management review, with the results identified in LRA Table 3.6.2.C-1 (as revised by the above-referenced NMPNS supplemental letter dated October 29, 2004).
The conductive materials for cables, connectors, splices, and terminal blocks that are within the scope of license renewal and subject to aging management review (AMR) include copper, tin-coated copper, copper-coated steel, copper-constantan, iron-constantan, and chromel-alumel.
For those components that are located in an adverse localized environment caused by radiation or heat, the aging effects requiring management are loss of electrical continuity due to radiation-induced oxidation or moisture intrusion. The credited aging management program is the Non-EQ Electrical Cables and Connections Program. These results are consistent with NUREG-1801, Table VI.A.
RAI 3.6.2.C-2 LRA Table 3.6 2 C-1 conveys that aging stressorsforfuse blocks are moisture, fatigue, ohmic heating, mechanical stress, vibration, thermal cycling, electrical transients, chemical contamination, oxidation, and corrosion. LRA Table 3.6 2. C-1 also conveys that these aging stressors, wshen operated in an air environment to which they are nformally exposed to, do not have a significant aging effect on the capability of copper, brass, steel, or alloy (the material from which fuse blocks are, in part, constructed) to provide electrical continuity. Additionally, the applicant indicates that the Fuse Holder Inspection Program is creditedfor identifying potential age-related degradationforfuse blocks. LRA Section B2. 1.35 also states that the Fruse Holder Inspection Program is limited toflse holders located outside of active devices that have aging effects requiring management. Based on the above, please provide information to justify the purpose and effectiveness of the Fuse Holder Inspection Program. Please also explain why the fuse block commodity that may performn safety-relatedfunction as per 10 CGFJ 54.21 (a)(1) does not require an AMR for managing its aging effects.
Response
The purpose of the Fuse Holder Inspection (EHI) Program is to manage the aging affects of the metallic clamps associated with fuse holders. The insulating material of the fuse holders is managed by the Non-EQ Electrical Cables and Connections Program described in LRA Section B2. 1.29. The reason for a separate program to manage the aging effects of the metallic clamps is that the aging stressors and detection methods are different. For the metallic clamps, the aging stressors include moisture, fatigue, ohmic heating, mechanical stress, vibration, thermal cycling, electrical transients, chemical contamination, oxidation, and corrosion. The detection method also needs to be different than that employed in the Non-EQ Electrical Cables and Connections Program since a visual inspection is not sufficient to detect the aging effects from the above stressors. Rather, the detection method will be a proven test for detecting deterioration of metallic clamps of the fuse holders, such as thermography, contact resistance testing, or other appropriate testing. The acceptance criteria utilized in the FHI Program will be commensurate with the specific test employed.
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The effectiveness of the FRI Program is realized based upon the identification of the appropriate aging effects, employment of suitable detection methods and corresponding acceptance criteria, and utilization of the corrective action program to evaluate and resolve unacceptable conditions.
The FIR Program will ensure that fuse holders will perform their intended function for the period of extended operation.
The FRI Program applies only to fuse holders that are not part of a larger assembly, but support safety-related and non-safety-related functions in which the failure of a fuse precludes a safety function from being accomplished. Fuse holders inside the enclosure of an active component, such as switchgear, power supplies, power inverters, battery chargers, and circuit boards, are considered to be piece parts of the larger assembly. Therefore, under 10 CFR 54.21, fuse holders that are parts of a larger assembly are considered outside the scope of license renewal. This definition of the scope of fuse holders to be managed by the FHI Program is consistent with the Staff's position described in the NRC letter dated March 10, 2003, titled "Interim Staff Guidance (ISG)-5 on the Identification and Treatment of Electrical Fuse Holders for License Renewal."
RAI 3.6.2.C-3 Table 3.62. C-1 of the LRA supplemental letter dated October 29, 2004, indicates that loss of electrical continuity and/or loss of intsulation resistance are significant aging effectsforfuse blocks. This table also indicates that there will be a loss of electrical continuity when copper, brass, steel, or alloy (the materialfrom whichfuse blocks are, in part, constructed) are subjected to an adverse localized environment caused by heat and radiation that is significantly more severe than the specified service conditionsforfuse blocks. It is not clear to the staff how the adverse localized environment will have a significant aging effect on copper, brass, steel, or alloy (the materialfrom whichfuse blocks, in part, are constructed). Please clarify NMP 's conclusion andprovide additional iyformation regarding aging management program for managing aging effects offuse blocks in the adverse localized environment so they can perform their intendedfunction as per 10 CFR 54.21 (a)(l).
Response
NMP has concluded that the metallic clamp of a fuse holder could experience a loss of electrical continuity if exposed to an adverse localized environment caused by heat or radiation. The aging stressors that could result in a loss of electrical continuity include: (1) thermal fatigue in the form of high resistance caused by ohmic heating, thermal cycling or electrical transients, and (2) mechanical fatigue caused by frequent manipulation of the fuse itself, vibration, chemical contamination, corrosion, or oxidation. These aging stressors are normally not significant since they are accounted for in the design of electrical circuits under the specified service conditions.
However, should an adverse localized environment be created due to unexpected operational conditions or other circumstances, the rate of aging can be appreciably increased. Therefore, NMPNS concluded that the metallic clamps of fuse holders could experience aging effects requiring management.
With respect to the program credited with managing the aging effects of the metallic clamps of fuse holders, NMPNS will implement a Fuse Holder Inspection (FMll) Program as described in Page 3 of 12
LRA Section B2.1.35. The FHI Program will employ testing methods that are sufficient to detect the aging stressors listed above. These test methods may include thermography, contact resistance testing, or other appropriate testing that may be proven at the time of implementation.
The testing will be conducted on a 10-year frequency, with the first tests performed prior to entering the period of extended operation. The 10-year frequency 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 frequency will provide two'data points during a 20-year period, which can be used to characterize the degradation rate. The acceptance criteria for the test will correspond to the test method employed. Any unacceptable conditions will be processed in accordance with the corrective action program for proper evaluation and resolution. The FII Program is a new program for NMP that will be implemented prior to the period of extended operation and will ensure that fuse holders will perform their intended function for the period of extended operation.
RAI 3.6.2.C-4 LRA Table 3. 0-1 defines adverse localized environment caused by heat or radiation to be a condition in a limited plant area that is significantly more severe than the specified service conditionsfor electrical equipment. The specified service conditionsfor electrical equipment are generally between 40TC and 90 O. GDC 4 of I0 CFR Part 50, Appendix A, and general industry practicesfor non-safety equipment require electrical equipment to be installed and operated wiithin its specified service conditions. The AMMR results presented in the LRA imply that some electrical equipment are located in some plant areas that are significantly more severe than the specified service conditionsfor electrical equipment. Please provide clarification for this discrepancy.
Response
The listing of an "adverse localized environment caused by heat or radiation" in LRA Table 3.0-1 is not intended to imply that NMIPNS has known plant areas that are more severe than those assumed in the original plant design. NMP I and NMP2 were designed such that electrical components are selected, installed, and operated within the specified service conditions. An adverse localized environment is a condition in a limited plant area that is significantly more severe than the specified service environment for the electrical equipment.
An adverse variation in environment is significant if it could appreciably increase the rate of aging of a component or have an immediate adverse effect on operability. While these environments should not exist, they may exist due to unforeseen operational conditions. As such, aging management programs will be implemented to look for signs of aging degradation and provide reasonable assurance that the intended functions of electrical cables and connections exposed to these adverse environments will be maintained consistent with the current licensing basis through the period of extended operation.
RAI 3.6.2.C-5 Aging management review, (AMR) resultspresented in LRA Table 3.6.2. C-2for non-segregated bits indicate that an environment consisting of air without significant moisture has no significant Page 4 of 12
aging effect on aluminum (the only identfied component partfrom which non-segregated bus is constructed). LRA Section B2.1.34 for the non-segregated bus inspection program describes that bus duct insulation material wiilt experience temperature rise due to energization which may cause age-related degradation during the extended period of operation. Table 3.6.2. C-2 indicates bits duct material to be only aluminum which does not require the effects of aging to be managed while LRA Section B2.1.34 indicates bus duct also includes insulation materialfor which an aging management program is required Please provide clarification for this discrepancy.
Response
NMPNS acknowledges that the LRA contained a discrepancy in that the non-segregated bus insulation material was included within the scope of the Non-Segregated Bus Inspection Program described in LRA Section B2. 1.34, but the corresponding aging management results were not included in LRA Table 3.6.2.C-2. The bus insulation is made of various organic polymers and is exposed to an Air environment. The corresponding aging effect is loss of insulation resistance, and the program to manage the aging effect is the Non-Segregated Bus Inspection Program.
LRA Revisions LRA Section 3.6.2.1.2 (page 3.6-4), under the "Materials" heading, is revised to add "Various Organic Polymers."
LRA Section 3.6.2.1.2 (page 3.6-4), under the "Aging Effect Requiring Management" heading, is revised to delete the existing sentence and replace it with the aging effect "Loss of Insulation Resistance."
LRA Section 3.6.2.1.2 (page 3.6-4), under the "Aging Management Programs" heading, is revised to delete the existing paragraph and replace it with "Non-Segregated Bus Inspection Program."
LRA Table 3.6.2.C-2 (page 3.6-11) is revised to incorporate the aging management results for the non-segregated bus insulation, as shown in Attachment 2.
RAI 3.6.2.C-6 Aging management review (AMR) results presented in LRIZ Table 3.6.2. C-2 for non-segregated/sivitchyard bus insulators indicate that an environment consisting of air without signifi cant moisture has no significant aging effect on cement, porcelain, and metal (the identified component partsfrom which insulators are constructed). LRA Section B2.1.34 conveys that the insulators used to insulate and support non-segregated bus will experience temperature rise due to bus energization which may cause age-related degradation (of cement, porcelain, and/or metal). Please provide clarificationfor this discrepancy.
As per 10 CFR 54.21(a)(1), if these insulators (used to insulate and support nonsegregated bus) experience temperature rise due to bus energization which may cause any signifi cant age-related Page 5 of 12
degradation during the period of extended operation, then these insulators will require an aging management program to manage their effects of aging. If these insulators (cement, porcelain, and/or metal to insulate and support non-segregated bus exposed to air environment) are within the scope of license renewal, please provide information regarding progranm(s) for managing their aging effects. If these insulators are not within the scope of license renewal, please provide information to justify their exclusion.
Additionally, please provide the expected temperature, radiation, wind, and precipitation of the subject air environment at NMP Nuclear Station to which insulators (used to insulate and support non-segregated bus) will be exposed during the period of extended operation.
Response
NMPNS acknowledges that there is an apparent discrepancy between LRA Section B2.1.34 and Table 3.6.2.C-2 regarding the aging management results for non-segregated bus insulators. The insulators are used to support and electrically insulate the non-segregated bus conductors. Since these components could experience a temperature rise due to bus energization, the aging effect of loss of insulation resistance will be added. The credited aging management program will continue to be the Non-Segregated Bus Inspection Program described in LRA Section B2.1.34.
With respect to the environmental parameters to which the non-segregated bus insulators are exposed, they are protected from outdoor weather by enclosures and are, therefore, not exposed to wind or rain. Radiation exposure is negligible due to their location in low dose areas of the station (i.e., less that 1 mrem/hour fields). The temperatures to which the insulators are exposed have not been directly measured; however, the design service temperature, including ohmic heating, is 105'C.
LRA Revisions LRA Section 3.6.2.1.2 (page 3.6-4), under the "Aging Effects Requiring Management" heading, is revised to delete the existing sentence and replace it with the aging effect "Loss of Insulation Resistance."
LRA Section 3.6.2.1.2 (page 3.6-4), under the "Aging Management Programs" heading, is revised to delete the existing paragraph and replace it with "Non-Segregated Bus Inspection Program."
LRA Table 3.6.2.C-2 (page 3.6-11) is revised to incorporate the aging management results for the non-segregated bus insulators, as shown in Attachment 2.
LRA Sections A1.1.27 and A2.1.27 are revised to incorporate the aging management results for the non-segregated bus insulators, as shown in Attachment 3.
LRA Section B2.1.34 is revised to incorporate the aging management results for the non-segregated bus insulators, as shown in Attachment 4.
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RAI 3.6.2.C-7 LRA Table 3.6.2.C-2 does not include results of the aging management review (AMR) of non-segregated and svitchyard bits connections. Please provide infornation to describe results of AMRfor electrical connections to non-segregated and switchyard buses at NMP.
Response
NMPNS acknowledges that the AMR results for the non-segregated and switchyard bus connections were not provided in LRA Table 3.6.2.C-2. The non-segregated bus connections are bolted connections made of aluminum and steel and are covered by the bus insulation. Even though these connections are normally inaccessible, they could experience an aging effect of loosening of bolted connections due to thermal cycling and ohmic heating. These connections will be managed by the Non-Segregated Bus Inspection Program, as described in LRA Section B2. 1.34. However, since they are normally inaccessible, they will only be tested when they are made accessible for other reasons (i.e., maintenance on the bus insulation or insulation removal to support other maintenance activities).
The switchyard connections are also bolted connections that require aging management. These components are made of aluminum and steel and exposed to an Air environment. They could experience an aging effect of loosening of bolted connections due to thermal cycling and ohmic heating. The NMP Preventive Maintenance Program is credited with managing the aging effects via the use of thermography to detect elevated temperatures. If elevated temperatures are detected, an evaluation is performed and corrective actions are implemented in accordance with the corrective action program.
The above described AMR results are being incorporated into the LRA, as indicated below.
LRA Revisions LRA Table 3.0-2 (page 3.0-11) is revised to add an Aging Effect of "Loosening of Bolted Connections" and corresponding Description of "A decrease in bolting tightness as applied to bolted electrical connections for the switchyard bus and transmission conductor connections."
LRA Section 3.6.2.1.2 (page 3.6-4), under the "Aging Effects Requiring Management" heading, is revised to delete the existing sentence and replace it with the aging effect "Loosening of Bolted Connections."
LRA Section 3.6.2.1.2 (page 3.6-4), under the "Aging Management Programs" heading, is revised to delete the existing paragraph and replace it with "Non-Segregated Bus Inspection Program" and "Preventive Maintenance Program."
LRA Table 3.6.2.C-2 (page 3.6-11) is revised to incorporate the aging management results for the non-segregated bus connectors and switchyard bus connectors, as shown in Attachment 2.
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LRA Sections Al. 1.27 and A2. i.27 are revised to incorporate the aging management results for the non-segregated bus connectors as shown in Attachment 3.
LRA Section B2. 1.34 is revised to incorporate the aging management results for the non-segregated bus connectors as shown in Attachment 4.
RAI 3.6.2.C-8 Based on information from the LIA, it is the staff's understanding that the aging effects of various organic polymers (the component partsfrom which containment electricalpenetrations are constructed) will be managed by the Non-EQ Electrical Cables and Connections Program at NAMP. Please confirmn if this understanding is correct and provide information, usingAAM]?
results for these various organic polymers, to explain how the Non-EQ Electrical Cables and Connections Program will be implemented and describe the effectiveness of this program in?
managing aging effectsfor the above-stated materialfor the period of extended operation.
Response
NMPNS confirms that the Staffs understanding is correct for the cable and connector subcomponents of the containment electrical penetrations. The Non-EQ Cable and Connections Program at NMPNS is credited with managing the aging effects of these subcomponents.
Should the various organic polymer portions of these subcomponents be exposed to adverse localized environments, they may experience a loss of insulation resistance due to embrittlement, cracking, melting, or discoloration. The Non-EQ Cable and Connections Program includes the electrical penetrations in the scope of components to be inspected. A representative sample of susceptible components will be inspected for signs of degradation on a 10-year frequency. If degradation is observed, an evaluation of the condition will be performed and corrective actions will be taken in accordance with the corrective action program. Based upon the attributes associated with this program, as described in NUREG-1 801,Section XI.E1, and as committed to in LRA Section B2. 1.29, there is reasonable assurance that the Non-EQ Cable and Connections Program will adequately manage the aging effects of the containment electrical penetrations to ensure their intended function will be maintained during the period of extended operation.
With respect to the seal subcomponents of the containment electrical penetrations, they are also constructed of various organic polymers. These subeomponents have a pressure boundary intended function and are managed by the ASME Section XI Inservice Inspection (Subsection IWE) and 10 CFR 50 Appendix J Programs, as described in LRA Sections B2.1.23 and B2.1.26, respectively. They may experience a loss of leak tightness aging effect due to deterioration of the materials. The inspection frequency for the ASME Section XI Inservice Inspection (Subsection IWE) Program is in accordance with the requirements of 10 CFR 50.55a and Subsection IWE of the ASME Code,Section XI. The 10 CFR 50 Appendix J Program testing is conducted on a two-year frequency to ensure that any leakage is identified and corrected prior to the loss of intended function.
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LRA Revisions LRA Section 3.6.2.1.3 (page 3.6-5), under the "Environment" heading, is revised to add the environment "Adverse localized environment caused by heat or radiation."
LRA Section 3.6.2.1.3 (page 3.6-5), under the "Aging Effects Requiring Management" heading, is revised to delete the existing sentence and replace it with the aging effects "Loss of Insulation Resistance" and "Loss of Leak Tightness."
LRA Section 3.6.2.1.3 (page 3.6-5), under the "Aging Management Programs" heading, is revised to delete the existing sentence and replace it with "Non-EQ Cables and Connections Program," "ASME Section XI Inservice Inspection (Subsection IWE) Program," and "10 CFR 50 Appendix J Program."
LRA Table 3.6.2.C-3 (page 3.6-12) is revised to incorporate the aging management results for containment electrical penetrations, as shown in Attachment 2.
RAI 3.6.2.C-9 LRA Table 3.6.2. C-4 does not inclhde the results of the aging management review (AMR) of transmission conductor connections. Please provide the AMR resultsfor transmission conductor coinnections at NMP.
Response
NMPNS acknowledges that the AMR results for transmission conductor connections were not included in LRA Table 3.6.2.C-4. These connections are generally bolted connections made of aluminum with steel bolts: They are exposed to an Air environment and could experience an aging effect of loosening of bolted connections due to thermal cycling and ohmic heating. The program credited for managing this aging effect is the Preventive Maintenance Program via the use of thermography to detect elevated temperatures at the bolted connections. If elevated temperatures are detected, an evaluation is performed and corrective actions implemented in accordance with the corrective action program.
LRA Revisions LRA Section 3.6.2.1.4 (page 3.6-6), under the "Aging Effects Requiring Management" heading, is revised to delete the existing sentence and replace it with the aging effect "Loosening of Bolted Connections."
LRA Section 3.6.2.1.4 (page 3.6-6), under the "Aging Management Programs" heading, is revised to delete the existing sentence and replace it with "Preventive Maintenance Program."
LRA Table 3.6.2.C-4 (page 3.6-13) is revised to add the aging management results for the transmission conductor connections, as shown in Attachment 2.
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RAI 3.6.2.C-10 Operating experience has shown that electrical buses in bits duct have failed dute to cracked insulation in the presence of moisture, debris buildup, and loosening of bits connecting bolts.
The aging management program (AMP) described in LRA Section B2. 1.34 coveys that buts duct insulation will be monitored/inspectedfor surface contamination. Monitoring/inspectionfor debris buildup and loosening of bits connecting bolts have not been addressed by the AMP.
Please explain why debris buildup and loosening of bus connecting bolts have not been included as part of the AMP.
Response
LRA Section B2.1.34, under the "Parameters Monitored/Inspected" heading, states that the program will visually inspect non-segregated bus duct internal components for surface anomalies, such as embrittlement, discoloration, cracking, chipping, or surface contamination, which could affect the life of the component. The use of the term "surface contamination" is intended to include "debris" type buildup on the phase buses that could potentially lead to the type of failures identified in NRC Information Notice (IN) 89-64.
The omission of the bolted connection inspection in LRA Section B2.1.34 was an oversight. The aging management review conducted by NMIP identified inspections of bolted connections as a program activity that is required. However, this activity was not stated in the LRA. The inspection of the bolted connections will be performed on a sample of accessible connections and will involve a torque test, resistance test, or other proven methods to ensure there is no degradation of electrical continuity. The inspection will be performed at least once every 10 years, with the initial inspection performed prior to the period of extended operation. This is an adequate period to identify failures of the bus ducts since experience has shown that aging degradation is a slow process. A 10-year inspection frequency will provide two data points during a 20-year period, which can be used to characterize the degradation rate.
LRA Revisions LRA Sections Al. 1.27 and A2. 1.27, "Non-Segregated Bus Inspection Program," and Section B2.1.34, "Non-Segregated Bus Inspection Program," are revised to incorporate the above described changes, as shown in Attachments 3 and 4, respectively.
RAI 3.6.2.C-1 1 The aging management program (AMP) described in LRA Section B2. 1.34 indicates that only accessible components of bits duct are inspected The AMP also states that the entire population of components is inspected Please provide information to describe how aging effects of inaccessible components are managed Page 10 of 12
l
Response
The NMPNS Non-Segregated Bus Inspection Program, as described in LRA Section B2. 1.34, is a new plant-specific program that is intended to manage the aging effects of the components comprising the in-scope non-segregated buses. While the majority of the components are accessible, some are not. In general, the inaccessible components are managed indirectly by monitoring the condition of the accessible components. When degradation is identified on accessible components, the evaluation will include whether similar conditions could exist on inaccessible components based upon factors such as material similarity, exposure to a similar environment for a similar duration, etc. If it is determined that inaccessible components could have a similar degraded condition, then action would be taken to address the condition. Forthe specific case of bolted connections that are inaccessible due to coverage by accessible insulation, the condition of the insulation could be related to the integrity of the bolted connection. For example, if an inaccessible bolted connection was becoming loose and generating more ohmic heat, then the insulation material covering the connection would show signs of degradation that would be observable. The evaluation of the cause for the insulation degradation would consider the bolted connection being loose. This could lead to testing the bolted connection for integrity of electrical connection. Therefore, the Non-Segregated Bus Inspection Program manages the aging of accessible and inaccessible components of the non-segregated buses that are within scope of license renewal.
RAT 3.6.2.C-12 The aging management program (AMP) described in LRA Section B2.1.34for bus duct states that the program is a condition monitoring program, which requires regular inspections of in-scope components and identification of degraded conditions that would affect the ability of the component to perform its intendedfunction. The AMP further states that the aging effects of bits duct at NMP ivill be detected through visual inspections at least once every 10 years.
The staff understands that the inspection will detect material suirface anomalies, which are precursors to aBy onset of insulation failure. Please provide additional iformation to clarify the following staff concerns:
- It is not clear why afrequenicy of ]Oyearsfor inspection is considered a regular inspection.
- Is this inspection frequtenicy adequate to preclude age-relatedfailtures of the conductor insulation?
- Is this inspection frequency adequate to prechide age relatedfailures ofthe bus instlation)?
Response
NMPNS provides the following responses to each of the bulleted RAI items, as follows:
(1) The statement regarding a "regular inspection" of the bus duct was not intended to correlate with the frequency of the inspections. The use of the term "regular" was intended to differentiate the inspection from a "special" one. As such, since the term has provided a source of misunderstanding, it will be deleted.
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(2) The inspection frequency of 10 years is considered adequate to preclude age-related failures of the conductor insulation since experience has shown that aging degradation is a slow process. The 10-year inspection interval will provide two data points during a 20-year period, which can be used to characterize the rate of degradation. The industry operating experience described in NRC IN 89-64 illustrates that bus insulation failures are mainly attributed to moisture or debris buildup. Since the bus duct is enclosed in a sealed, metal enclosure that contains a controlled environment (heated), there is reasonable assurance that further deterioration of the material due to moisture or debris will not occur between subsequent 10-year inspections.
(3) The inspection frequency of 10 years is considered adequate to preclude age-related failures of the bus insulation for the same reasons as described in (2) above.
LRA Revisions LRA Section B2. 1.34, "Non-Segregated Bus Inspection Program," is revised to incorporate the above-described changes, as shown in Attachment 4.
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ATTACHMENT 2 Nine Mile Point Nuclear Station Revisions to LRA Tables 3.6.2.C-2, 3.6.2.C-3, and 3.6.2.C-4 Page 1 of 4
Table 3.6.2.C-2 Electrical and l&C Systems Non-Segregated/Switchyard Bus - Summary of Aging Management Evaluation IneddAging Effect NUREG-lComponentType Intended Material Environment Requiring Aging Management 1801 Table I Notes Copnn ye Function Management Program Volume 2 Item Non-Segregated EC Aluminum Air None Non-Segregated Bus 1, 5 Bus
._._._._._Inspection Program No..Se'r ted EG Aluminum,Steel Air Loe ening qf Non-S..reg.tedBus
,us Conne or.
BRolted Ispectton program NonSegr w
e'g'ated E
Cement Air None None None Bus Insulators NFS Porcelain Air Lo-SS OfNonSegated Bus Metal Air None None None E!
MOa i
~,cOi s
....,,,,,~
A"'
Non-Se...........ted ElV~o$Ogno ArLo of N6n4e'regate Bus J
Switchyard Bus EC Aluminum Air None None None yaRds EC.
Atnpinum, Steel Ain Loosening"of reeie c
'Bont Maintranc, e_
CM~c t n r g a i_
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Table 3.6.2.C-3 Electrical and l&C Systems Containment Electrical Penetrations - Summary of Aging Management Evaluation' IneddAging Effect NUREG-Component Type uIntedeo Material Environment Requiring Aging Management 1801 Table I loe FucinManagement Program Volume 2 Item Noe Containment EC various Organic Adve'r tems's sf a n 0 0zN S.
s
... F Electrical Polymers Ioare ns 110000 bd-nnec0tfion
- lAA, 36.3 3 6 Penetrations nv,.ini....
Re.ss.ance
- Pogram, 1P3B Various Organic Air f Le k 10 eFR
- Appn dl i RB 4.,a 3*§ 8 6,
6 Polymers tess I rogra nS B..,
Inpcto u
tion JW
________..o.r...
' The structural steel portion of the primary containment electrical penetrations is evaluated in the NMP1 Primary Containment Structure (Table 3.5.2.A-1) and the NMP2 Primary Containment Structure (Table 3.5.2.B-1).
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Table 3.6.2.C-4 Electrical and l&C Systems Switchyard Components - Summary of Aging Management Evaluation IneddAging Effect NUREG-Component Type lIunctionde Material Environment Re ring lAging Management 1801 Table I Notes Copnn ye Function Matrilnnvrometmequrngrga Volume 2 Item Managemen ProgramItem High Voltage El Cement Air None None None Insulators NFS Porcelain Air None None None Metal Air None None None Transmission EC Aluminum Air None None None Conductors Conductor-Steel Reinforced on E Auminum, Steel
,Ait Loase ing of IJ Conduc'tie'to'n.
l
.tte Mar n e C o n e c ~ o o n n ~ i h
~
P r g r m_
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ATTACHMENT 3 Nine Mile Point Nuclear Station Revisions to LRA Sections A1.1.27 and A2.1.27 Revise the first paragraphs in LRA Sections A1.1.27 (page A1-12) and A2.1.27 (page A2-12) to delete the existing third sentence and replace it with the following:
Neetei L ciacknd u
reision
- ebis,
.tpe aM mosture; 4sua1-mspections othn bus Q
8SB.in~s::
vter 8i detect v SjB tI Zent caci, S
nltns; ss~g; liirtn, Xd@discbcriortio t
t...
em en
.S p.nf..C.tios,
Page I of 1
ATTACHMENT 4 Nine Mile Point Nuclear Station Revisions to LRA Section B2.1.34 Page 1 of 4
Revisions to LRA Section B2.1.34 The following is a complete copy of LRA Section B2. 1.34 (pages B-66 through B-68), with the changes described in the RAI responses shaded.
B2.1.34 NON-SEGREGATED BUS INSPECTION PROGRAM The Non-Segregated Bus Inspection Program is a new plant-specific program that will consist of the appropriate ten elements described in Appendix A of NUREG-800 (Reference 1). This program inspects components and materials internal to the non-segregated bus ducts that connect the reserve auxiliary transformers to the 4160V buses required for the recovery of offsite power to both units following a Station Blackout (SBO) event. This inspection program considers the technical information and guidance provided in References 20, 21, 22, and 23. This program will be implemented prior to the period of extended operation.
Aging Management Program Elements The key elements of aging management activities, which are used in the Non-Segregated Bus Inspection Program, are described below. The results of an evaluation of each key element against the appropriate ten elements described in Appendix A of NUREG-1800 are provided below.
Scope of Program Jh1p~~~~pi' ot~
dis~hi thJ~p flCee~se re~a1; non-segregated bus ducts that connect the reserve auxiliary transformers to the 4160V buses required for the recovery of offsite power to both units following an SBO event.
Preventive Actions
>&°..
~ ~
~
~
~
~
~
~
~
~
~
~
t't
.gi..t.,,,..
Aa.t,,i,,p Y Parameters Monitored/Inspected W
~
m gaYple pf (bus! joiht Vind enng
'Vices le
~heck'ed for r6 er trqueI I Ibobte...i 0%keb e~k1diisgih`
Xe5@~~ip nX~.,P r t.;
.;<S,.,
fiiftuse
- nicr6-6hxi tei~n~ ofe stffcin Nzrih ca
- :.ity>>f.~f:s.t tla
'~ -
fomiecton>Th roga $
\\tilI 1s hpec thehiteg3rnal po
>onspaccassiboe B$~t eirc~c~,,~cis~,OTregnder,Kduy,'uild Ad b
Page 2 of 4
Detection of Aging Effects ina)t anne In....tOf, Montorusing andtem anTreending(~sua~s riu~l~
Accepstance Cievea bFfothninfcZitianY AO-jea icense m
'eVgrSi IC) eaSdisfe&
Thisfis'aZAi i
Zd~qtif t
s....sA.
erjnsptionfspqpoe wi<.
-i6td Corctv Actionaceie h~aaio~t Monitoring acind Trendicmng e
sn h E
rcss h
ult suac Moitringra Toiand tRending wApniB ntob usedforec thi randSe "Exeptions to Refrence-3 Accueptnce Ch MN omtett h
orcieato riteriaof1 F50 Append~ix B (Refaerenceilita 3).s Theat duP Corcive Action dProgramtincludest th n
~didetftonl and correectioecni ofcodit~io nsi adverse to unalietyandte ietfcation as dteriat ion, tcorrection, anid iacitoionss to minimized recurrencfo sinfct codtonsidnactbl Corrcfirtive Actones Corctv ctos r ocmntduinyh DE rcs.TeQult suac Program Topical Report (Appendix B to Reference 12 andAn te c
Appendix B oReference w3). n Te dumen Cor thiv Sation progcea fionlds to the icdection and Crrction a
o ct adverse ton quatyon the identio cue doreterineAction, correctioens eiw and atosominisz recrfrmenc for significant conditions adverse.
to quliy Corrective ActionEfetvnsReiwanispromdfrsgicntodtos Page 3 of 4
adverse to quality and selected hardware related conditions adverse to quality. The Corrective Action Program includes, but is not limited to, safety-related, non-safety related and fire protection SSCs. Therefore, those SSCs required to be in-scope for License Renewal are addressed as part of the current Corrective Action Program.
Administrative Controls The Non-Segregated Bus Inspection Program will be implemented through documents that are subject to administrative controls. The administrative controls for NMPNS are discussed in the plant's Conduct of Operations description (Section XIII in Reference 12 and Chapter 13 in Reference 13) and the Quality Assurance Program Topical Report (Appendix B to Reference 12 and Appendix B to Reference 13).
Operating Experience The Non-Segregated Bus Inspection Program is a new program at NMPNS; therefore, no programmatic operating experience is available. As operating experience is obtained, lessons learned will be used to adjust this program as needed.
Exceptions to NUREG-1800 Program Elements Affected Monitoring and Trending Over a 20 year inspection period, some data may be available which will permit a subjective determination of degradation rates. However, proceduralized analytical trending will not be included in this activity because the parameters inspected are not readily quantifiable in an appropriate form.
Enhancements None Conclusion There is reasonable assurance that aging effects will be managed by the implementation of the Non-Segregated Bus Inspection Program such that SSCs WSLR will continue to perform their intended functions consistent with the current licensing basis for the period of extended operation.
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