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| issue date = 06/24/2008 | | issue date = 06/24/2008 | ||
| title = NRC Response to Virginia Electric and Power Company, North Anna Power Station Units 1 & 2 Letter Dated May 21, 2008, from D. G. Stoddard, Site Vice President to Victor M. Mccree, Deputy Regional Administrator for Operations | | title = NRC Response to Virginia Electric and Power Company, North Anna Power Station Units 1 & 2 Letter Dated May 21, 2008, from D. G. Stoddard, Site Vice President to Victor M. Mccree, Deputy Regional Administrator for Operations | ||
| author name = Wert L | | author name = Wert L | ||
| author affiliation = NRC/RGN-II/DRP | | author affiliation = NRC/RGN-II/DRP | ||
| addressee name = Christian D | | addressee name = Christian D | ||
| addressee affiliation = Virginia Electric & Power Co (VEPCO) | | addressee affiliation = Virginia Electric & Power Co (VEPCO) | ||
| docket = 05000338, 05000339 | | docket = 05000338, 05000339 | ||
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=Text= | =Text= | ||
{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II SAM NUNN ATLANTA FEDERAL CENTER | {{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II SAM NUNN ATLANTA FEDERAL CENTER 61 FORSYTH STREET, SW, SUITE 23T85 ATLANTA, GEORGIA 30303-8931 June 24, 2008 Mr. David A. Christian President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060 | ||
==SUBJECT:== | ==SUBJECT:== | ||
NRC RESPONSE TO VIRGINIA ELECTRIC AND POWER COMPANY, | NRC RESPONSE TO VIRGINIA ELECTRIC AND POWER COMPANY, NORTH ANNA POWER STATION UNITS 1 & 2 - LETTER DATED MAY 21, 2008, FROM D. G. STODDARD, SITE VICE PRESIDENT TO VICTOR M. | ||
MCCREE, DEPUTY REGIONAL ADMINISTRATOR FOR OPERATIONS | |||
==Dear Mr. Christian:== | ==Dear Mr. Christian:== | ||
I am writing in response to the letter dated May 21, 2008, in which North Anna Power Station documented Virginia Electric and Power | I am writing in response to the letter dated May 21, 2008, in which North Anna Power Station documented Virginia Electric and Power Companys disagreement with the assignment of cross-cutting aspects for violations of regulatory requirements in NRC Inspection Report 05000338, 339/2008002. In the letter, Mr. Stoddard did not dispute the violations of regulatory requirements, but disagreed with three of the cross-cutting aspect assignments. | ||
The letter from North Anna Power Station, stated that; During the re-exit meeting, several changes to the cross-cutting aspects and other modifications to the report were identified. | |||
The letter from North Anna Power Station, stated that; | Dominion did not have sufficient time to evaluate and respond to these changes prior to the Inspection Report being approved by NRC management. | ||
During NRC management review of the inspection report, in accordance with NRC policy, the resident inspectors were in contact with the North Anna Power Station licensing staff each time changes were made as conclusions changed. This was to ensure that changes were communicated in a timely fashion. These communications continued up until the report was finalized. | During NRC management review of the inspection report, in accordance with NRC policy, the resident inspectors were in contact with the North Anna Power Station licensing staff each time changes were made as conclusions changed. This was to ensure that changes were communicated in a timely fashion. These communications continued up until the report was finalized. | ||
The North Anna Power Station letter further stated that; | The North Anna Power Station letter further stated that; In these examples, the process of identifying cross-cutting aspects has been neither predictable nor objective and the end results appear to be subjective. The frequency of reclassification only reinforces the necessity for a common understanding with and agreement by the licensee before issuance to preclude a perception of managed overall outcomes. | ||
The process that was implemented by NRC Region II was from Inspection Manual Chapter (IMC) 0305, | The process that was implemented by NRC Region II was from Inspection Manual Chapter (IMC) 0305, Operating Reactor Assessment Program, dated 11/27/07. The pertinent applicable guidance (Section 06.07 a.1.) reads as follows: | ||
During the inspection activity, the finding (and any subsequent developments associated with the issue) must be reviewed by the inspector to identify the cause(s) associated with the cross-cutting areas, if any exists. The level of | |||
VEPCO 2 information available on the cause(s) for an issue is normally commensurate with the significance of the issue. For risk significant issues, licensees will typically perform a root cause evaluation. While for low risk issues, licensees will typically perform an apparent cause evaluation. Inspectors should identify the cross-cutting aspects of the finding, if any exists, using available causal information. | |||
The inspectors should identify the cause(s) that provides the most meaningful insight into the performance deficiency. | |||
In order to support the evaluation of findings with cross-cutting aspects, the inspectors should provide sufficient detail in the plant issues matrix and provide periodic updates as new information becomes available. | |||
Furthermore, IMC 0308, Attachment 3, Significance Determination Process Basis Document, dated October 16, 2006, specifies that the determination of cause does not need to be based on a rigorous root-cause evaluation (which might require a licensee months to complete), but rather on a reasonable assessment and judgment of the staff. | |||
The Reactor Oversight Process (ROP) is an independent assessment of the licensees performance. While consideration of a licensees position on a finding or cross-cutting aspect is an important part of the ROP, independence is maintained throughout the assessment process. | |||
As noted above, if a licensee provides additional information, the NRC will evaluate that additional information and technical basis for inclusion into the assessment process. | |||
For the specific three findings with cross-cutting aspects in question, the apparent cause performed by the North Anna staff determined what caused the conditions but provided little or no detailed causal factor information into why or how the findings occurred. In accordance with findings of very low safety significance, the inspectors gathered available causal information obtained from record reviews and interviews with personnel. Re-classifying the cross-cutting aspects reflected a conscientious effort by the Region II report reviewers, along with the resident inspectors, to assign the most appropriate cross-cutting aspects. Based upon the available information, the reason for the inadequate procedures or failure to follow procedures was not available and thus the assignment of these as being the cross-cutting aspects were deemed to be the most meaningful insight into the performance deficiency. Our review also noted that within the previous four quarters, cross-cutting aspects involving decision making and not maintaining design margins have been assigned to inspection findings associated with North Anna. | For the specific three findings with cross-cutting aspects in question, the apparent cause performed by the North Anna staff determined what caused the conditions but provided little or no detailed causal factor information into why or how the findings occurred. In accordance with findings of very low safety significance, the inspectors gathered available causal information obtained from record reviews and interviews with personnel. Re-classifying the cross-cutting aspects reflected a conscientious effort by the Region II report reviewers, along with the resident inspectors, to assign the most appropriate cross-cutting aspects. Based upon the available information, the reason for the inadequate procedures or failure to follow procedures was not available and thus the assignment of these as being the cross-cutting aspects were deemed to be the most meaningful insight into the performance deficiency. Our review also noted that within the previous four quarters, cross-cutting aspects involving decision making and not maintaining design margins have been assigned to inspection findings associated with North Anna. | ||
The NRC has carefully reviewed the documentation provided to support Virginia Electric and Power | The NRC has carefully reviewed the documentation provided to support Virginia Electric and Power Companys positions. Based upon our review, which included NRC personnel external to Region II and not involved in the development of Inspection Report 05000338, 339/2008002, we have concluded, for the reasons outlined in the attached enclosure, that the three cross-cutting aspects were appropriately classified and documented in Inspection Report 05000338, 339/2008002. The attached enclosure includes the referenced non-cited violations and associated cross-cutting aspects, the basis provided in the North Anna letter for disagreement with the assigned cross-cutting-aspects, and the NRCs evaluation. | ||
In accordance with 10 CFR 2.390 of the | VEPCO 3 In addition, during a telephone conversation between Mr. Stoddard and Mr. McCree on May 5, 2008, Mr. Stoddard expressed concern that 100 percent of findings for the North Anna Power Station were assigned cross-cutting aspects. By definition, a performance deficiency must be within the licensees ability to prevent and consequently the majority of findings are assigned cross-cutting aspects. The primary exception is that a cross-cutting aspect must also represent current licensee performance. The inspection program assigned to the resident inspectors typically involves validation of current licensee actions or emergent issues, and usually involves current licensee performance. For contrast, design verification inspections may involve findings which occurred under processes and procedures which have undergone substantial changes and hence would not reflect the current performance of those processes and procedures. Our review indicated that all the findings issued for North Anna Units 1 and 2 for the previous four quarters have been associated with current processes. | ||
The NRC is committed to objective and accurate assessments of licensee performance. As such, we will continue our efforts to assign cross-cutting aspects by identified causes that provide the most meaningful insights into each performance deficiency. | |||
In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its enclosure will be made available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room). | |||
Please contact me at (404) 562-4500 with any questions you may have regarding this letter. | Please contact me at (404) 562-4500 with any questions you may have regarding this letter. | ||
Sincerely, | Sincerely, | ||
/RA/ | |||
Docket Nos.: 50-338, 50-339 License Nos.: NPF-4, NPF-7 | Leonard D. Wert, Jr., Director Division of Reactor Projects Docket Nos.: 50-338, 50-339 License Nos.: NPF-4, NPF-7 | ||
==Enclosure:== | ==Enclosure:== | ||
As stated | As stated cc w/encl. (See page 4) | ||
cc w/encl. | OFFICE RII:DRP RII:DRP RII:DRP SIGNATURE /RA/ /RA/ /RA/ | ||
NAME LGarner JMoorman EGuthrie DATE 6/ /2008 6/ /2008 6/ /2008 6/ /2008 6/ /2008 6/ /2008 6/ /2008 E-MAIL COPY? YES NO YES NO YES NO YES NO YES NO YES NO YES NO VEPCO 4 cc w/encl: | |||
Chris L. Funderburk Eugene S. Grecheck Director, Nuclear Licensing & Operations Vice President, Nuclear Development Support Dominion Resources Services, Inc. | |||
Virginia Electric and Power Company Electronic Mail Distribution Electronic Mail Distribution Leslie N. Hartz Eric Hendrixson Vice President, Nuclear Support Services Director, Nuclear Safety and Licensing Dominion Resources Services, Inc. | |||
Virginia Electric and Power Company 5000 Dominion Boulevard Electronic Mail Distribution Glen Allen, VA 23061 Daniel G. Stoddard Michael M. Cline Site Vice President Director Virginia Electric and Power Company Virginia Department of Emergency Services Electronic Mail Distribution Management Electronic Mail Distribution Mark D. Sartain Director Nuclear Safety and Licensing Virginia Electric & Power Company Electronic Mail Distribution Executive Vice President Old Dominion Electric Cooperative Electronic Mail Distribution Lillian M. Cuoco, Esq. | |||
Senior Counsel Dominion Resources Services, Inc. | |||
Electronic Mail Distribution Attorney General Supreme Court Building 900 East Main Street Richmond, VA 23219 Senior Resident Inspector Virginia Electric and Power Company North Anna Power Station U.S. NRC P.O. Box 490 Mineral, VA 23117 County Administrator Louisa County P.O. Box 160 Louisa, VA 23093 | |||
VEPCO 5 Letter to David A. Christian from Leonard D. Wert, Jr. dated June 24, 2008 | |||
==SUBJECT:== | |||
NRC RESPONSE TO VIRGINIA ELECTRIC AND POWER COMPANY, NORTH ANNA POWER STATION UNITS 1 & 2 - LETTER DATED MAY 21, 2008, FROM D. G. STODDARD, SITE VICE PRESIDENT TO VICTOR M. | |||
MCCREE, DEPUTY REGIONAL ADMINISTRATOR FOR OPERATIONS Distribution w/encl: | |||
C. Evans, RII L. Slack, RII OE Mail RIDSNRRDIRS PUBLIC S. P. Lingam, NRR R. Jervey, NRR | |||
NRC RESPONSE TO VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 & 2 LETTER DATED MAY 21, 2008, FROM D. G. STODDARD, SITE VICE PRESIDENT TO VICTOR M. MCCREE, DEPUTY REGIONAL ADMINISTRATOR FOR OPERATIONS 1-RC-P-1A Oil Collection System Referenced Non-Cited Violation NCV (05000339/2008002-01), Failure to Adequately Install an Oil Collection System on a Reactor Coolant Pump Motor) (Section 1R05) | |||
Green. The inspectors identified a non-cited violation of the North Anna Power Plant Facility Renewed Operating Licensee NPF-7, Condition D, Fire Protection Program, which involved a failure to adequately install a section of the oil collection system on the Unit 2 A reactor coolant pump motor. The licensee entered this issue into their corrective action program and took prompt action to repair the problem. | |||
The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of protection against external factors such as fire. This finding had a credible impact on safety because the inadequate installation of the oil collection system presented a degradation of a fire confinement component which has a fire prevention function of not allowing an oil leak to reach hot surfaces. | |||
The finding was of very low safety significance or Green because of the low degradation rating of the fire confinement category related to the oil collection system. The cause of this finding involved the cross-cutting area of human performance, the component of resources and the aspect of complete, accurate and up-to-date procedures, H.2(c), because the procedure was not adequate to ensure all bolting material was correctly installed. | |||
Licensee Response to Cross-Cutting Aspects Assigned: Dominion does not dispute the NCV (non-cited violation), but believes that no cross-cutting aspect should be assigned due to the indeterminate nature of the cause of the event. Specifically, assigning an aspect when, neither the aspect nor component of the cross-cutting area can be factually established, is an arbitrary application of the process. If an aspect must be assigned, the cross-cutting aspect that is more likely applicable is Procedural Compliance, even though that cant be proven either. | |||
The basis for our observation is provided below. | |||
Maintenance procedures were revised in 2000 based on Plant Issue N-1999-2404-R1, Missing Fasteners on RCP (reactor coolant pump) Pump/Motor Oil Collection System. Electrical Maintenance Procedure 0-ECM-1405-02 included the requirement to ensure all mounting bolts and cap screws for the oil collection system are in place. The requirement is included within a step that is performed during an upper bearing insulation check. | |||
In February 2008, 0-ECM-1435-02 was used to disconnect the Unit 2 A RCP motor. Based on information received from craft personnel, the RCP oil collection system was not removed. | |||
Craft personnel disconnected the power for the oil lift pump through a small opening in the oil collection canning. The steps to perform the upper bearing insulation check were not applicable. | |||
Enclosure | |||
2 A review of the work order history for the Unit 2 A RCP for 2008 was performed. None of the work orders would have removed the RCP oil collection system. Therefore, the exact cause is unknown. Although we agree that proper placement of all mounting bolts and cap screws for the oil collection system would be enhanced by moving the requirement from the conditional step in 0-ECM-1404-02 to a stand alone step, the enhancement potential of a procedure is not a definitive basis to establish casual effect or assign a cross-cutting aspect. | |||
NRC Evaluation: | |||
During the inspection period, the inspectors evaluated the causal information provided by the licensee via verbal feedback and a corrective action report deficiency statement. No causal factor determination or root cause evaluation was conducted by the licensee during the inspection report period. | |||
The inspectors determined that procedure, 0-ECM-1405-02, Reactor Coolant Pump Motor General Disconnect, Revision 19, governed electrical maintenance activities for the RCP motor oil collection system enclosure of concern. This procedure had previously been revised by Plant Issue N-1999-2404 R1 to include an action for ensuring that fasteners in the oil collection system were installed. The 1999 issue was missing fasteners that presented a seismic concern (no mention of a fire protection concern). This Plant Issue revised six procedures of which 0-ECM-1405-02 was one. However, the inspectors noted that the procedure was revised with the bolting verification step inside a conditional step, whereas, procedure 0-MCM-0110-02, associated with the lower oil collection system, was revised to be in a non-conditional step. | |||
Allowing this step to be N/A because it was conditional in nature, did not meet the intent of the revision. This conclusion was confirmed by discussions with licensee staff. The inspectors concluded that the procedure, as written, was correctly performed, e.g. the conditional steps containing the bolting verification was properly marked as N/A. Furthermore, through the review of the procedure, its revision history, and corrective action documents, and personnel interviews, the inspectors independently determined the causal factors related to this issue. | |||
The inspectors were unable to determine why the oil collection system was improperly installed. | |||
However, the steps in the procedure were intended to serve as a final barrier to prevent operation with a degraded oil confinement system. Not having the instruction as a stand alone step was considered as an important insight into licensees performance. The inadequate procedure was a causal factor to the performance deficiency and the failure to comply with regulatory requirements. Based upon available information, the inspectors determined that the causal factor, which provided the most meaningful insight into the performance deficiency, was an inadequate procedure. Thus, the most significant contributor to the performance deficiency was determined to be the cross-cutting area of human performance, the component of resources and the aspect of complete, accurate and up-to-date procedures, H.2(c), because the procedure was not adequate to ensure all bolting material was correctly installed as originally intended by the licensees corrective action program. | |||
Containment Sump Gap Measurement Referenced Non-Cited Violation NCV (05000339/2008002-04), Inadequate Design Control Involving Unit 2 Containment Sump Strainer Gaps (Section 1R20.2) | |||
Green. A Green NRC-identified non-cited violation of 10 CFR 50, Appendix B, Criterion III, Design Control, was identified for inadequate design control measures to assure that the | |||
3 measurement technique used to verify the gaps between Unit 2 containment sump strainer modules were within the design particle retention size and the acceptance criteria for spacing between modules. The licensee entered the condition into their corrective action program and inspected all the gaps and either corrected or evaluated any gaps which exceeded the installation procedure acceptance criteria. This issue had previously been addressed on Unit 1. | |||
The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of design control. The finding was of very low safety significance or Green because it did not result in an actual loss of safety function. The cause of this finding involved the cross-cutting area of human performance, the component of resources and the aspect of complete and accurate procedures and work packages H.2(c), because the licensee failed to establish an adequate method to verify that the installed configuration of the containment sump strainer met the design specification. | The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of design control. The finding was of very low safety significance or Green because it did not result in an actual loss of safety function. The cause of this finding involved the cross-cutting area of human performance, the component of resources and the aspect of complete and accurate procedures and work packages H.2(c), because the licensee failed to establish an adequate method to verify that the installed configuration of the containment sump strainer met the design specification. | ||
Licensee Response to Cross-Cutting Aspects Assigned | Licensee Response to Cross-Cutting Aspects Assigned: Dominion does not dispute the NCV, but believes the cross-cutting aspect that is more applicable to the issue is Human Performance/Decision Making/Conservative Assumptions. The basis for our observation is provided below. | ||
: | North Anna used the go-no-go flat feeler gauges to measure the gap of the sump strainer seal strip during installation of the GSI-191 sump strainers at the recommendation of AECL. | ||
North Anna used the go-no-go flat feeler gauges to measure the gap of the sump strainer seal strip during installation of the GSI-191 sump strainers at the recommendation of AECL. Although, this method of measurement turned out not to be adequate, the procedure was developed as a direct application of the design and use of the go-no-go flat feeler gauge was included at the recommendation of the designer. | Although, this method of measurement turned out not to be adequate, the procedure was developed as a direct application of the design and use of the go-no-go flat feeler gauge was included at the recommendation of the designer. | ||
The inadequacy of the designers recommendation and Dominions acceptance of that recommendation is a failure in decision making and applying conservative assumptions rather than an inherent deficiency in procedure development. Rather than changing procedures as a corrective action, Engineering is reviewing an alternate design for sealing the sump strainer and methods for measuring any gaps to ensure the design margin continues to be met. | |||
The inadequacy of the | NRC Evaluation: | ||
NRC Evaluation | |||
: | |||
The NRC applies the conservative decision making cross-cutting aspect to broader applications which involve conscious decisions involving safety rather than a technical inadequacy. | The NRC applies the conservative decision making cross-cutting aspect to broader applications which involve conscious decisions involving safety rather than a technical inadequacy. | ||
Therefore, the NRC does not consider this scenario applicable to the cross-cutting aspect proposed by the licensee. | Therefore, the NRC does not consider this scenario applicable to the cross-cutting aspect proposed by the licensee. | ||
The inspectors concluded that | The inspectors concluded that licensees procedure allowed the use of a flawed measurement technique for design verification of the gaps between Unit 2 containment sump strainer modules to determine if they were within the design particle retention size and the acceptance criteria for spacing between modules. The licensee agreed with this conclusion based on the generated corrective action assignments. | ||
During the inspection period, the inspectors independently determined the causal factors related to this issue through review of the procedure, its revision history, and corrective action documents, and personnel interviews. No causal factors were determined by the licensee | During the inspection period, the inspectors independently determined the causal factors related to this issue through review of the procedure, its revision history, and corrective action documents, and personnel interviews. No causal factors were determined by the licensee | ||
4 during the inspection period. The inspectors were not able to determine why the vendor specified an improper measurement device; or the cause or basis of the quality assurance process associated with the screen installation failing to detect the unacceptable gaps. The inspectors concluded that the most reasonable proximate cause for the performance deficiency was inadequate work instructions. This was determined to be a significant contribution to the performance deficiency. Hence the most significant contributor was determined to be the cross-cutting area of human performance, the component of resources and the aspect of complete and accurate procedures and work packages H.2(c). | |||
2-FW-P-2 TDAFW Trip Linkage Measurement Referenced Non-Cited Violation NCV (05000339/2008002-05), Spurious Turbine Driven Auxiliary Feedwater Pump Trip Due to Failure to Adequately Implement Procedure (Section 4OA2.2) | |||
Green. The inspectors identified a non-cited violation of Technical Specification 5.4.1a for a failure to adequately implement maintenance procedure requirements for the turbine driven auxiliary feedwater pump (TDAFWP) which, consequently, led to a spurious trip of the TDAFWP, following a reactor trip, on December 25, 2007. The licensee's corrective actions included repair of the affected TDAFWP components and procedure revisions to ensure accurate dimensional checks. | Green. The inspectors identified a non-cited violation of Technical Specification 5.4.1a for a failure to adequately implement maintenance procedure requirements for the turbine driven auxiliary feedwater pump (TDAFWP) which, consequently, led to a spurious trip of the TDAFWP, following a reactor trip, on December 25, 2007. The licensee's corrective actions included repair of the affected TDAFWP components and procedure revisions to ensure accurate dimensional checks. | ||
The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of equipment reliability. The finding was of low safety significance or Green based upon both the motor driven auxiliary feedwater pumps being available and the subsequent manual restart of the TDAFWP. The cause of the finding was related to the cross-cutting area of human performance, the component of work practices and the aspect involving procedure compliance, H.4(b), because the licensee failed to adequately implement a maintenance procedure step to identify unacceptable component dimensions. (Section 4OA2.2) | The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of equipment reliability. | ||
Licensee Response to Cross-Cutting Aspects Assigned | The finding was of low safety significance or Green based upon both the motor driven auxiliary feedwater pumps being available and the subsequent manual restart of the TDAFWP. The cause of the finding was related to the cross-cutting area of human performance, the component of work practices and the aspect involving procedure compliance, H.4(b), because the licensee failed to adequately implement a maintenance procedure step to identify unacceptable component dimensions. (Section 4OA2.2) | ||
: | Licensee Response to Cross-Cutting Aspects Assigned: Dominion does not dispute the NCV, but believes the cross-cutting aspect is more directly applicable to the issue is Human Performance/Resources/Proper Maintenance. The basis for our observation is provided below. | ||
Following the over speed trip of the TDAFW pump, the tappet nut to head lever engagement was measured to be 0,020 inches. This is outside the critical dimension specified in maintenance procedure 2-MPM-0102-01. | Following the over speed trip of the TDAFW pump, the tappet nut to head lever engagement was measured to be 0,020 inches. This is outside the critical dimension specified in maintenance procedure 2-MPM-0102-01. | ||
2-MPM-0102-01 specifies that the correct engagement for the tappet nut to head lever for the trip linkage is 0.030 to 0.060 inches. This critical dimension is consistent with the vendor manual and the EPRI documentation. Neither of these documents or 2-MPM-0102-01 specifies the method of measuring the critical dimension. The method for measuring the proper engagement of the tappet nut to head lever was provided by a vendor representative. The method used was taking an imprint on a piece of paper and then measuring the imprint. | 2-MPM-0102-01 specifies that the correct engagement for the tappet nut to head lever for the trip linkage is 0.030 to 0.060 inches. This critical dimension is consistent with the vendor manual and the EPRI documentation. Neither of these documents or 2-MPM-0102-01 specifies the method of measuring the critical dimension. The method for measuring the proper engagement of the tappet nut to head lever was provided by a vendor representative. The method used was taking an imprint on a piece of paper and then measuring the imprint. | ||
There was some degree of looseness in the tappet nut assembly due to wear, which was subsequently corrected during the forced outage from the reactor trip. This looseness could | There was some degree of looseness in the tappet nut assembly due to wear, which was subsequently corrected during the forced outage from the reactor trip. This looseness could | ||
5 have resulted in some variability between measurements. In evaluating the condition, we conclude that it is possible that the engagement was within tolerance the last time it was checked, regardless of the measurement method used. | |||
As part of the RCE (root cause evaluation), it was identified that there was industry experience from a St. Lucie TDAFW pump over speed trip. The vendor representative at St. Lucie recommended using a dial caliper to measure the critical dimension because the dial caliper is a more accurate measurement method. | |||
With the maintenance procedure, 2-MPM-01 02-01, specifying the correct engagement for the trip linkage and implementing the recommended measurement method of the vendor representative, it was believed that the proper maintenance practices were being implemented to ensure operability of the TDAFW pump. 2-MPM-0102-01 was complied with. Only with the recent receipt of industry experience from St Lucie has a more accurate method been identified as recommended to determine engagement of the tappet nut to head lever within critical dimensions. Accordingly, we believe the cross-cutting aspect that is more directly applicable is Proper Maintenance. | With the maintenance procedure, 2-MPM-01 02-01, specifying the correct engagement for the trip linkage and implementing the recommended measurement method of the vendor representative, it was believed that the proper maintenance practices were being implemented to ensure operability of the TDAFW pump. 2-MPM-0102-01 was complied with. Only with the recent receipt of industry experience from St Lucie has a more accurate method been identified as recommended to determine engagement of the tappet nut to head lever within critical dimensions. Accordingly, we believe the cross-cutting aspect that is more directly applicable is Proper Maintenance. | ||
NRC Evaluation | NRC Evaluation: | ||
Causal information provided to the inspectors by the licensee, during the inspection report period, included verbal feedback and a root cause evaluation document. The inspectors independently determined the causal factors related to this issue through review of the procedure, its revision history, and corrective action documents, and personnel interviews. The inspectors reviewed the licensees maintenance training program to determine the maintenance practices employed by the technicians to perform tasks utilizing the correct instrumentation based on the necessary accuracy. The inspectors found that "North Anna and Surry Power Stations, Power Station Electrician/Mechanic Development Program (Nuclear), Self-Study Module 1.6, Tools", Section 4, "Coarse Measurement Tools," Part A, "Types of Measurement," | |||
and "Basic Shop Math," Section on "Measurement," and topics of "Accuracy vs. Precision," and "Tolerance," established practices concerning accuracy of measurements. Because of the specified engagement of .030 to .060 inches, the measurement technique and equipment utilized during the Fall 2007 refueling outage did not meet the established practices. The inspectors determined that, considering the training provided, procedure 2-MPM-0102-01 provided sufficient information to perform the tappet measurement correctly. | |||
The licensee uses procedure VPAP-0801 to govern control of vendors. The inspectors concluded that the licensee failed to adhere to these requirements because they failed to ensure the vendor complied with the basic maintenance training standards relating to the measurement accuracy. Therefore, there were two failures of procedure adherence, VPAP-0801 and 2-MPM-0102-01 with the noncompliance of 2-MPM-0102-01 as the most immediate cause of the performance deficiency. | The licensee uses procedure VPAP-0801 to govern control of vendors. The inspectors concluded that the licensee failed to adhere to these requirements because they failed to ensure the vendor complied with the basic maintenance training standards relating to the measurement accuracy. Therefore, there were two failures of procedure adherence, VPAP-0801 and 2-MPM-0102-01 with the noncompliance of 2-MPM-0102-01 as the most immediate cause of the performance deficiency. | ||
The inspectors did agree that the exact cause for the as-found out-of-tolerance was not known. | |||
However, through review of the facts surrounding the failure, the inspectors discarded wear as a credible cause, since the tappet adjustment had been performed within the previous four months. Furthermore, the inspectors observed that a more precise measuring technique, as specified in your skill-of-craft training, would most likely have detected excessive looseness or | |||
6 an incorrect adjustment of the tappet assembly. Thus, the inspectors reasonably concluded that the imprecise measuring technique was a significant contributor to the tappet assembly being left such that it resulted in the TDAFW pump trip on December 25, 2007. Accordingly, because your procedures and practices were not followed, the causal factor associated with procedure compliance was considered to be the most significant contributor to the performance deficiency. | |||
Therefore, the most meaningful insight into the performance deficiency as related to current performance was determined to be the cross-cutting area of human performance, the component of work practices, and the aspect involving procedure compliance, H.4(b), because the licensee failed to adequately implement a maintenance procedure step to identify unacceptable component dimensions.}} |
Latest revision as of 01:37, 13 March 2020
ML081760595 | |
Person / Time | |
---|---|
Site: | North Anna ![]() |
Issue date: | 06/24/2008 |
From: | Wert L Division Reactor Projects II |
To: | Christian D Virginia Electric & Power Co (VEPCO) |
References | |
IR-08-002 | |
Download: ML081760595 (12) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II SAM NUNN ATLANTA FEDERAL CENTER 61 FORSYTH STREET, SW, SUITE 23T85 ATLANTA, GEORGIA 30303-8931 June 24, 2008 Mr. David A. Christian President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060
SUBJECT:
NRC RESPONSE TO VIRGINIA ELECTRIC AND POWER COMPANY, NORTH ANNA POWER STATION UNITS 1 & 2 - LETTER DATED MAY 21, 2008, FROM D. G. STODDARD, SITE VICE PRESIDENT TO VICTOR M.
MCCREE, DEPUTY REGIONAL ADMINISTRATOR FOR OPERATIONS
Dear Mr. Christian:
I am writing in response to the letter dated May 21, 2008, in which North Anna Power Station documented Virginia Electric and Power Companys disagreement with the assignment of cross-cutting aspects for violations of regulatory requirements in NRC Inspection Report 05000338, 339/2008002. In the letter, Mr. Stoddard did not dispute the violations of regulatory requirements, but disagreed with three of the cross-cutting aspect assignments.
The letter from North Anna Power Station, stated that; During the re-exit meeting, several changes to the cross-cutting aspects and other modifications to the report were identified.
Dominion did not have sufficient time to evaluate and respond to these changes prior to the Inspection Report being approved by NRC management.
During NRC management review of the inspection report, in accordance with NRC policy, the resident inspectors were in contact with the North Anna Power Station licensing staff each time changes were made as conclusions changed. This was to ensure that changes were communicated in a timely fashion. These communications continued up until the report was finalized.
The North Anna Power Station letter further stated that; In these examples, the process of identifying cross-cutting aspects has been neither predictable nor objective and the end results appear to be subjective. The frequency of reclassification only reinforces the necessity for a common understanding with and agreement by the licensee before issuance to preclude a perception of managed overall outcomes.
The process that was implemented by NRC Region II was from Inspection Manual Chapter (IMC) 0305, Operating Reactor Assessment Program, dated 11/27/07. The pertinent applicable guidance (Section 06.07 a.1.) reads as follows:
During the inspection activity, the finding (and any subsequent developments associated with the issue) must be reviewed by the inspector to identify the cause(s) associated with the cross-cutting areas, if any exists. The level of
VEPCO 2 information available on the cause(s) for an issue is normally commensurate with the significance of the issue. For risk significant issues, licensees will typically perform a root cause evaluation. While for low risk issues, licensees will typically perform an apparent cause evaluation. Inspectors should identify the cross-cutting aspects of the finding, if any exists, using available causal information.
The inspectors should identify the cause(s) that provides the most meaningful insight into the performance deficiency.
In order to support the evaluation of findings with cross-cutting aspects, the inspectors should provide sufficient detail in the plant issues matrix and provide periodic updates as new information becomes available.
Furthermore, IMC 0308, Attachment 3, Significance Determination Process Basis Document, dated October 16, 2006, specifies that the determination of cause does not need to be based on a rigorous root-cause evaluation (which might require a licensee months to complete), but rather on a reasonable assessment and judgment of the staff.
The Reactor Oversight Process (ROP) is an independent assessment of the licensees performance. While consideration of a licensees position on a finding or cross-cutting aspect is an important part of the ROP, independence is maintained throughout the assessment process.
As noted above, if a licensee provides additional information, the NRC will evaluate that additional information and technical basis for inclusion into the assessment process.
For the specific three findings with cross-cutting aspects in question, the apparent cause performed by the North Anna staff determined what caused the conditions but provided little or no detailed causal factor information into why or how the findings occurred. In accordance with findings of very low safety significance, the inspectors gathered available causal information obtained from record reviews and interviews with personnel. Re-classifying the cross-cutting aspects reflected a conscientious effort by the Region II report reviewers, along with the resident inspectors, to assign the most appropriate cross-cutting aspects. Based upon the available information, the reason for the inadequate procedures or failure to follow procedures was not available and thus the assignment of these as being the cross-cutting aspects were deemed to be the most meaningful insight into the performance deficiency. Our review also noted that within the previous four quarters, cross-cutting aspects involving decision making and not maintaining design margins have been assigned to inspection findings associated with North Anna.
The NRC has carefully reviewed the documentation provided to support Virginia Electric and Power Companys positions. Based upon our review, which included NRC personnel external to Region II and not involved in the development of Inspection Report 05000338, 339/2008002, we have concluded, for the reasons outlined in the attached enclosure, that the three cross-cutting aspects were appropriately classified and documented in Inspection Report 05000338, 339/2008002. The attached enclosure includes the referenced non-cited violations and associated cross-cutting aspects, the basis provided in the North Anna letter for disagreement with the assigned cross-cutting-aspects, and the NRCs evaluation.
VEPCO 3 In addition, during a telephone conversation between Mr. Stoddard and Mr. McCree on May 5, 2008, Mr. Stoddard expressed concern that 100 percent of findings for the North Anna Power Station were assigned cross-cutting aspects. By definition, a performance deficiency must be within the licensees ability to prevent and consequently the majority of findings are assigned cross-cutting aspects. The primary exception is that a cross-cutting aspect must also represent current licensee performance. The inspection program assigned to the resident inspectors typically involves validation of current licensee actions or emergent issues, and usually involves current licensee performance. For contrast, design verification inspections may involve findings which occurred under processes and procedures which have undergone substantial changes and hence would not reflect the current performance of those processes and procedures. Our review indicated that all the findings issued for North Anna Units 1 and 2 for the previous four quarters have been associated with current processes.
The NRC is committed to objective and accurate assessments of licensee performance. As such, we will continue our efforts to assign cross-cutting aspects by identified causes that provide the most meaningful insights into each performance deficiency.
In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its enclosure will be made available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Please contact me at (404) 562-4500 with any questions you may have regarding this letter.
Sincerely,
/RA/
Leonard D. Wert, Jr., Director Division of Reactor Projects Docket Nos.: 50-338, 50-339 License Nos.: NPF-4, NPF-7
Enclosure:
As stated cc w/encl. (See page 4)
OFFICE RII:DRP RII:DRP RII:DRP SIGNATURE /RA/ /RA/ /RA/
NAME LGarner JMoorman EGuthrie DATE 6/ /2008 6/ /2008 6/ /2008 6/ /2008 6/ /2008 6/ /2008 6/ /2008 E-MAIL COPY? YES NO YES NO YES NO YES NO YES NO YES NO YES NO VEPCO 4 cc w/encl:
Chris L. Funderburk Eugene S. Grecheck Director, Nuclear Licensing & Operations Vice President, Nuclear Development Support Dominion Resources Services, Inc.
Virginia Electric and Power Company Electronic Mail Distribution Electronic Mail Distribution Leslie N. Hartz Eric Hendrixson Vice President, Nuclear Support Services Director, Nuclear Safety and Licensing Dominion Resources Services, Inc.
Virginia Electric and Power Company 5000 Dominion Boulevard Electronic Mail Distribution Glen Allen, VA 23061 Daniel G. Stoddard Michael M. Cline Site Vice President Director Virginia Electric and Power Company Virginia Department of Emergency Services Electronic Mail Distribution Management Electronic Mail Distribution Mark D. Sartain Director Nuclear Safety and Licensing Virginia Electric & Power Company Electronic Mail Distribution Executive Vice President Old Dominion Electric Cooperative Electronic Mail Distribution Lillian M. Cuoco, Esq.
Senior Counsel Dominion Resources Services, Inc.
Electronic Mail Distribution Attorney General Supreme Court Building 900 East Main Street Richmond, VA 23219 Senior Resident Inspector Virginia Electric and Power Company North Anna Power Station U.S. NRC P.O. Box 490 Mineral, VA 23117 County Administrator Louisa County P.O. Box 160 Louisa, VA 23093
VEPCO 5 Letter to David A. Christian from Leonard D. Wert, Jr. dated June 24, 2008
SUBJECT:
NRC RESPONSE TO VIRGINIA ELECTRIC AND POWER COMPANY, NORTH ANNA POWER STATION UNITS 1 & 2 - LETTER DATED MAY 21, 2008, FROM D. G. STODDARD, SITE VICE PRESIDENT TO VICTOR M.
MCCREE, DEPUTY REGIONAL ADMINISTRATOR FOR OPERATIONS Distribution w/encl:
C. Evans, RII L. Slack, RII OE Mail RIDSNRRDIRS PUBLIC S. P. Lingam, NRR R. Jervey, NRR
NRC RESPONSE TO VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 & 2 LETTER DATED MAY 21, 2008, FROM D. G. STODDARD, SITE VICE PRESIDENT TO VICTOR M. MCCREE, DEPUTY REGIONAL ADMINISTRATOR FOR OPERATIONS 1-RC-P-1A Oil Collection System Referenced Non-Cited Violation NCV (05000339/2008002-01), Failure to Adequately Install an Oil Collection System on a Reactor Coolant Pump Motor) (Section 1R05)
Green. The inspectors identified a non-cited violation of the North Anna Power Plant Facility Renewed Operating Licensee NPF-7, Condition D, Fire Protection Program, which involved a failure to adequately install a section of the oil collection system on the Unit 2 A reactor coolant pump motor. The licensee entered this issue into their corrective action program and took prompt action to repair the problem.
The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of protection against external factors such as fire. This finding had a credible impact on safety because the inadequate installation of the oil collection system presented a degradation of a fire confinement component which has a fire prevention function of not allowing an oil leak to reach hot surfaces.
The finding was of very low safety significance or Green because of the low degradation rating of the fire confinement category related to the oil collection system. The cause of this finding involved the cross-cutting area of human performance, the component of resources and the aspect of complete, accurate and up-to-date procedures, H.2(c), because the procedure was not adequate to ensure all bolting material was correctly installed.
Licensee Response to Cross-Cutting Aspects Assigned: Dominion does not dispute the NCV (non-cited violation), but believes that no cross-cutting aspect should be assigned due to the indeterminate nature of the cause of the event. Specifically, assigning an aspect when, neither the aspect nor component of the cross-cutting area can be factually established, is an arbitrary application of the process. If an aspect must be assigned, the cross-cutting aspect that is more likely applicable is Procedural Compliance, even though that cant be proven either.
The basis for our observation is provided below.
Maintenance procedures were revised in 2000 based on Plant Issue N-1999-2404-R1, Missing Fasteners on RCP (reactor coolant pump) Pump/Motor Oil Collection System. Electrical Maintenance Procedure 0-ECM-1405-02 included the requirement to ensure all mounting bolts and cap screws for the oil collection system are in place. The requirement is included within a step that is performed during an upper bearing insulation check.
In February 2008, 0-ECM-1435-02 was used to disconnect the Unit 2 A RCP motor. Based on information received from craft personnel, the RCP oil collection system was not removed.
Craft personnel disconnected the power for the oil lift pump through a small opening in the oil collection canning. The steps to perform the upper bearing insulation check were not applicable.
Enclosure
2 A review of the work order history for the Unit 2 A RCP for 2008 was performed. None of the work orders would have removed the RCP oil collection system. Therefore, the exact cause is unknown. Although we agree that proper placement of all mounting bolts and cap screws for the oil collection system would be enhanced by moving the requirement from the conditional step in 0-ECM-1404-02 to a stand alone step, the enhancement potential of a procedure is not a definitive basis to establish casual effect or assign a cross-cutting aspect.
NRC Evaluation:
During the inspection period, the inspectors evaluated the causal information provided by the licensee via verbal feedback and a corrective action report deficiency statement. No causal factor determination or root cause evaluation was conducted by the licensee during the inspection report period.
The inspectors determined that procedure, 0-ECM-1405-02, Reactor Coolant Pump Motor General Disconnect, Revision 19, governed electrical maintenance activities for the RCP motor oil collection system enclosure of concern. This procedure had previously been revised by Plant Issue N-1999-2404 R1 to include an action for ensuring that fasteners in the oil collection system were installed. The 1999 issue was missing fasteners that presented a seismic concern (no mention of a fire protection concern). This Plant Issue revised six procedures of which 0-ECM-1405-02 was one. However, the inspectors noted that the procedure was revised with the bolting verification step inside a conditional step, whereas, procedure 0-MCM-0110-02, associated with the lower oil collection system, was revised to be in a non-conditional step.
Allowing this step to be N/A because it was conditional in nature, did not meet the intent of the revision. This conclusion was confirmed by discussions with licensee staff. The inspectors concluded that the procedure, as written, was correctly performed, e.g. the conditional steps containing the bolting verification was properly marked as N/A. Furthermore, through the review of the procedure, its revision history, and corrective action documents, and personnel interviews, the inspectors independently determined the causal factors related to this issue.
The inspectors were unable to determine why the oil collection system was improperly installed.
However, the steps in the procedure were intended to serve as a final barrier to prevent operation with a degraded oil confinement system. Not having the instruction as a stand alone step was considered as an important insight into licensees performance. The inadequate procedure was a causal factor to the performance deficiency and the failure to comply with regulatory requirements. Based upon available information, the inspectors determined that the causal factor, which provided the most meaningful insight into the performance deficiency, was an inadequate procedure. Thus, the most significant contributor to the performance deficiency was determined to be the cross-cutting area of human performance, the component of resources and the aspect of complete, accurate and up-to-date procedures, H.2(c), because the procedure was not adequate to ensure all bolting material was correctly installed as originally intended by the licensees corrective action program.
Containment Sump Gap Measurement Referenced Non-Cited Violation NCV (05000339/2008002-04), Inadequate Design Control Involving Unit 2 Containment Sump Strainer Gaps (Section 1R20.2)
Green. A Green NRC-identified non-cited violation of 10 CFR 50, Appendix B, Criterion III, Design Control, was identified for inadequate design control measures to assure that the
3 measurement technique used to verify the gaps between Unit 2 containment sump strainer modules were within the design particle retention size and the acceptance criteria for spacing between modules. The licensee entered the condition into their corrective action program and inspected all the gaps and either corrected or evaluated any gaps which exceeded the installation procedure acceptance criteria. This issue had previously been addressed on Unit 1.
The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of design control. The finding was of very low safety significance or Green because it did not result in an actual loss of safety function. The cause of this finding involved the cross-cutting area of human performance, the component of resources and the aspect of complete and accurate procedures and work packages H.2(c), because the licensee failed to establish an adequate method to verify that the installed configuration of the containment sump strainer met the design specification.
Licensee Response to Cross-Cutting Aspects Assigned: Dominion does not dispute the NCV, but believes the cross-cutting aspect that is more applicable to the issue is Human Performance/Decision Making/Conservative Assumptions. The basis for our observation is provided below.
North Anna used the go-no-go flat feeler gauges to measure the gap of the sump strainer seal strip during installation of the GSI-191 sump strainers at the recommendation of AECL.
Although, this method of measurement turned out not to be adequate, the procedure was developed as a direct application of the design and use of the go-no-go flat feeler gauge was included at the recommendation of the designer.
The inadequacy of the designers recommendation and Dominions acceptance of that recommendation is a failure in decision making and applying conservative assumptions rather than an inherent deficiency in procedure development. Rather than changing procedures as a corrective action, Engineering is reviewing an alternate design for sealing the sump strainer and methods for measuring any gaps to ensure the design margin continues to be met.
NRC Evaluation:
The NRC applies the conservative decision making cross-cutting aspect to broader applications which involve conscious decisions involving safety rather than a technical inadequacy.
Therefore, the NRC does not consider this scenario applicable to the cross-cutting aspect proposed by the licensee.
The inspectors concluded that licensees procedure allowed the use of a flawed measurement technique for design verification of the gaps between Unit 2 containment sump strainer modules to determine if they were within the design particle retention size and the acceptance criteria for spacing between modules. The licensee agreed with this conclusion based on the generated corrective action assignments.
During the inspection period, the inspectors independently determined the causal factors related to this issue through review of the procedure, its revision history, and corrective action documents, and personnel interviews. No causal factors were determined by the licensee
4 during the inspection period. The inspectors were not able to determine why the vendor specified an improper measurement device; or the cause or basis of the quality assurance process associated with the screen installation failing to detect the unacceptable gaps. The inspectors concluded that the most reasonable proximate cause for the performance deficiency was inadequate work instructions. This was determined to be a significant contribution to the performance deficiency. Hence the most significant contributor was determined to be the cross-cutting area of human performance, the component of resources and the aspect of complete and accurate procedures and work packages H.2(c).
2-FW-P-2 TDAFW Trip Linkage Measurement Referenced Non-Cited Violation NCV (05000339/2008002-05), Spurious Turbine Driven Auxiliary Feedwater Pump Trip Due to Failure to Adequately Implement Procedure (Section 4OA2.2)
Green. The inspectors identified a non-cited violation of Technical Specification 5.4.1a for a failure to adequately implement maintenance procedure requirements for the turbine driven auxiliary feedwater pump (TDAFWP) which, consequently, led to a spurious trip of the TDAFWP, following a reactor trip, on December 25, 2007. The licensee's corrective actions included repair of the affected TDAFWP components and procedure revisions to ensure accurate dimensional checks.
The finding was more than minor because it impacted the mitigating systems cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences, and the related attribute of equipment reliability.
The finding was of low safety significance or Green based upon both the motor driven auxiliary feedwater pumps being available and the subsequent manual restart of the TDAFWP. The cause of the finding was related to the cross-cutting area of human performance, the component of work practices and the aspect involving procedure compliance, H.4(b), because the licensee failed to adequately implement a maintenance procedure step to identify unacceptable component dimensions. (Section 4OA2.2)
Licensee Response to Cross-Cutting Aspects Assigned: Dominion does not dispute the NCV, but believes the cross-cutting aspect is more directly applicable to the issue is Human Performance/Resources/Proper Maintenance. The basis for our observation is provided below.
Following the over speed trip of the TDAFW pump, the tappet nut to head lever engagement was measured to be 0,020 inches. This is outside the critical dimension specified in maintenance procedure 2-MPM-0102-01.
2-MPM-0102-01 specifies that the correct engagement for the tappet nut to head lever for the trip linkage is 0.030 to 0.060 inches. This critical dimension is consistent with the vendor manual and the EPRI documentation. Neither of these documents or 2-MPM-0102-01 specifies the method of measuring the critical dimension. The method for measuring the proper engagement of the tappet nut to head lever was provided by a vendor representative. The method used was taking an imprint on a piece of paper and then measuring the imprint.
There was some degree of looseness in the tappet nut assembly due to wear, which was subsequently corrected during the forced outage from the reactor trip. This looseness could
5 have resulted in some variability between measurements. In evaluating the condition, we conclude that it is possible that the engagement was within tolerance the last time it was checked, regardless of the measurement method used.
As part of the RCE (root cause evaluation), it was identified that there was industry experience from a St. Lucie TDAFW pump over speed trip. The vendor representative at St. Lucie recommended using a dial caliper to measure the critical dimension because the dial caliper is a more accurate measurement method.
With the maintenance procedure, 2-MPM-01 02-01, specifying the correct engagement for the trip linkage and implementing the recommended measurement method of the vendor representative, it was believed that the proper maintenance practices were being implemented to ensure operability of the TDAFW pump. 2-MPM-0102-01 was complied with. Only with the recent receipt of industry experience from St Lucie has a more accurate method been identified as recommended to determine engagement of the tappet nut to head lever within critical dimensions. Accordingly, we believe the cross-cutting aspect that is more directly applicable is Proper Maintenance.
NRC Evaluation:
Causal information provided to the inspectors by the licensee, during the inspection report period, included verbal feedback and a root cause evaluation document. The inspectors independently determined the causal factors related to this issue through review of the procedure, its revision history, and corrective action documents, and personnel interviews. The inspectors reviewed the licensees maintenance training program to determine the maintenance practices employed by the technicians to perform tasks utilizing the correct instrumentation based on the necessary accuracy. The inspectors found that "North Anna and Surry Power Stations, Power Station Electrician/Mechanic Development Program (Nuclear), Self-Study Module 1.6, Tools", Section 4, "Coarse Measurement Tools," Part A, "Types of Measurement,"
and "Basic Shop Math," Section on "Measurement," and topics of "Accuracy vs. Precision," and "Tolerance," established practices concerning accuracy of measurements. Because of the specified engagement of .030 to .060 inches, the measurement technique and equipment utilized during the Fall 2007 refueling outage did not meet the established practices. The inspectors determined that, considering the training provided, procedure 2-MPM-0102-01 provided sufficient information to perform the tappet measurement correctly.
The licensee uses procedure VPAP-0801 to govern control of vendors. The inspectors concluded that the licensee failed to adhere to these requirements because they failed to ensure the vendor complied with the basic maintenance training standards relating to the measurement accuracy. Therefore, there were two failures of procedure adherence, VPAP-0801 and 2-MPM-0102-01 with the noncompliance of 2-MPM-0102-01 as the most immediate cause of the performance deficiency.
The inspectors did agree that the exact cause for the as-found out-of-tolerance was not known.
However, through review of the facts surrounding the failure, the inspectors discarded wear as a credible cause, since the tappet adjustment had been performed within the previous four months. Furthermore, the inspectors observed that a more precise measuring technique, as specified in your skill-of-craft training, would most likely have detected excessive looseness or
6 an incorrect adjustment of the tappet assembly. Thus, the inspectors reasonably concluded that the imprecise measuring technique was a significant contributor to the tappet assembly being left such that it resulted in the TDAFW pump trip on December 25, 2007. Accordingly, because your procedures and practices were not followed, the causal factor associated with procedure compliance was considered to be the most significant contributor to the performance deficiency.
Therefore, the most meaningful insight into the performance deficiency as related to current performance was determined to be the cross-cutting area of human performance, the component of work practices, and the aspect involving procedure compliance, H.4(b), because the licensee failed to adequately implement a maintenance procedure step to identify unacceptable component dimensions.