IR 05000263/2005011
| ML053130251 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 10/13/2005 |
| From: | Dave Hills NRC/RGN-III/DRS/EB1 |
| To: | Conway J Nuclear Management Co |
| References | |
| IR-05-011 | |
| Download: ML053130251 (16) | |
Text
October 13, 2005
SUBJECT:
MONTICELLO NUCLEAR GENERATING PLANT NRC EVALUATION OF CHANGES, TESTS, OR EXPERIMENTS AND PERMANENT PLANT MODIFICATIONS BASELINE INSPECTION REPORT 05000263/2005011(DRS)
Dear Mr. Conway:
On September 16, 2005, the US Nuclear Regulatory Commission (NRC) completed a combined baseline inspection of the Evaluation of Changes, Tests, or Experiments and Permanent Plant Modifications at the Monticello Nuclear Generating Plant. The enclosed report documents the results of the inspection, which were discussed with you and others of your staff at the completion of the inspection on September 16, 2005.
The inspectors examined activities conducted under your license as they relate to safety and compliance with the Commissions rules and regulations and with the conditions of your license.
The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel.
Based on the results of the inspection, one NRC identified finding, which involved a violation of NRC requirements of very low safety significance, was identified. Because of the very low safety significance of the violation and the fact that the issue was entered into the licensees corrective action program the NRC is treating the finding as a Non-Cited Violation in accordance with Section VI.A.1 of the NRCs Enforcement Policy.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be 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).
Sincerely,
/RA/
David E. Hills, Chief Engineering Branch 1 Division of Reactor Safety Docket No. 50-263 License No. DPR-22 Enclosure:
Inspection Report 05000263/2005011(DRS)
cc w/encl:
J. Cowan, Executive Vice President and Chief Nuclear Officer Manager, Regulatory Affairs J. Rogoff, Vice President, Counsel, and Secretary Nuclear Asset Manager, Xcel Energy, Inc.
Commissioner, Minnesota Department of Health R. Nelson, President Minnesota Environmental Control Citizens Association (MECCA)
Commissioner, Minnesota Pollution Control Agency D. Gruber, Auditor/Treasurer, Wright County Government Center Commissioner, Minnesota Department of Commerce Manager - Environmental Protection Division Minnesota Attorney Generals Office
SUMMARY OF FINDINGS
IR 05000263/2005011(DRS); 09/12/2005 - 09/16/2005; Monticello Nuclear Generating Plant;
Evaluation of Changes, Tests, or Experiments (10 CFR 50.59).
The inspection covered a one-week announced baseline inspection on evaluations of changes, tests or experiments and permanent plant modifications. The inspection was conducted by four regional based engineering inspectors. One Green finding associated with a Non-Cited Violation was identified. The significance of most findings is indicated by their color (Green,
White, Yellow, Red) using Inspection Manual Chapter 0609, Significance Determination Process (SDP). Findings for which the SDP does not apply may be Green, or be assigned a severity level after NRC management review. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 3, dated July 2000.
A.
Inspector-Identified and Self-Revealed Findings
Cornerstone: Mitigating Systems
- Green.
A finding of very low safety significance was identified by the inspectors for a violation of 10 CFR 50, Appendix B, Criterion V. The licensee failed to establish and accomplish procedures that were appropriate to the circumstances to ensure that flood protection equipment would remain available during an internal flooding event in order to protect safety-related equipment. Specifically, the inspectors identified loose debris in the East Turbine Building (elevation 931') that had the potential to block drainage paths.
The licensee failed to implement procedures for controlling loose material that could have adversely impacted flood protection equipment and therefore safety-related motor control centers (MCCs) during an internal flooding event. In addition, the procedure that controlled loose material was not safety-related although the equipment that it affected was safety-related. The licensee entered the issue into their corrective action program to secure the loose material and to perform a cause evaluation.
The finding was more than minor because the failure to have adequate internal flood protection controls could have impacted the availability, reliability, and capability of the safety-related MCCs in flood-affected areas of the turbine building. In the event of a pipe break, loose material could have blocked water passage through floor drains or clearances under doors. The finding also affected the cross-cutting area of Problem Identification and Resolution because the failure to have adequate debris control procedures and instructions was previously identified by the NRC. The finding was of very low safety significance because the inspectors determined that some of the drainage paths would have remained available, and operators would have had time to prevent adverse affects to the redundant safety-related MCC. (Section 1R02)
Licensee-Identified Violations
No findings of significance were identified.
REPORT DETAILS
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity
1R02 Evaluations of Changes, Tests, or Experiments
.1 Review of 10 CFR 50.59 Evaluations and Screenings
a. Inspection Scope
From September 12 through 16, 2005, the inspectors reviewed six evaluations performed pursuant to 10 CFR 50.59. The inspectors confirmed that the evaluations were thorough and that prior NRC approval was obtained as appropriate. The inspectors also reviewed 13 screenings where licensee personnel had determined that a 10 CFR 50.59 evaluation was not necessary. In regard to the changes reviewed where no 10 CFR 50.59 evaluation was performed, the inspectors verified that the changes did not meet the threshold to require a 10 CFR 50.59 evaluation. The evaluations and screenings were chosen based on risk significance after considering samples from the different cornerstones and from permanent plant modifications, setpoint changes, procedure changes, conditions adverse to quality, and changes to the updated final safety analysis report. The list of documents reviewed by the inspectors is included as an attachment to this report.
The inspectors used, in part, Nuclear Energy Institute (NEI) 96-07, Guidelines for 10 CFR 50.59 Implementation, Revision 1, to determine acceptability of the completed evaluations and screenings. The NEI document was endorsed by the NRC in Regulatory Guide 1.187, Guidance for Implementation of 10 CFR 50.59, Changes, Tests, and Experiments, dated November 2000. The inspectors also consulted Part 9900 of the NRC Inspection Manual, 10 CFR Guidance for 10 CFR 50.59, Changes, Tests, and Experiments.
b. Findings
Introduction:
The inspectors identified a Non-Cited Violation (NCV) of 10 CFR 50, Appendix B, Criterion V having very low safety significance (Green) for the licensees failure to establish and accomplish adequate procedures to ensure that flood protection equipment would remain available during an internal flooding event in order to protect essential equipment.
Description:
During the review of a 10 CFR 50.59 evaluation, Evaluation No. 03-0002, Internal Flooding Modifications - Condenser Room Core Drill, the inspectors noted that the design change was cancelled. The proposed design change addressed a postulated scenario in which a seismic event could have caused a break in a non-seismically qualified 2.5" firewater pipe in the East Turbine Building (elevation 931').
The 10 CFR 50.59 evaluation for this design change stated that the floor drains on this elevation could have been plugged by loose materials, which would have resulted in the loss of safety-related Motor Control Center, MCC-143, which supplied emergency power to engineered safety systems. If the source of the flood had not been isolated, the water could have propagated under Doors 26 and 414 and down to the 911' elevation where it could have rendered the redundant safety-related MCC, MCC-133, inoperable.
The design change was to drill a hole in a wall separating a pit in the East Turbine Building (elevation 911') and the condenser room. This would have created a flow path for the water from the pit on the 911' elevation to the condenser room so that the water in the 911' elevation would not affect MCC-133. Licensee personnel informed the inspectors that this design change was cancelled because drilling a hole between two fire protection areas would have resulted in a breach of a fire barrier.
The inspectors asked licensee personnel how the flooding issue was resolved, and the response was that loose materials in the East Turbine Building (elevation 931') were controlled by the non-safety related procedure 4 AWI-04.02.01, Housekeeping. The purpose of controlling loose materials was to prevent the materials from plugging the floor drains in the event of an internal flood. The inspectors performed a walkdown of the East Turbine Building (elevation 931') and found that the following materials were not controlled per the licensees housekeeping procedure: loose paint chips on a wall, loose ductwork insulation, an unlatched rad protection cabinet with loose items inside (binders, tape), plastic or rubber foreign material exclusion signs on top of another cabinet, a loose phonebook, and a plastic floor duster. On September 14, 2005, licensee staff entered this issue into their corrective action program as CAP040752 and took immediate corrective actions to remove or secure the loose materials identified during the walkdown.
The licensees Updated Safety Analysis Report (USAR), Section 12.2.1.7.2, Internal Flooding, stated that an evaluation was performed for the possibility that flooding could prevent engineered safety systems from performing their emergency function following postulated accidents for lines not classified as high energy lines. The USAR also stated that there was adequate separation of redundant components of safeguards equipment (i.e., MCC-143 and MCC-133) so that no single failure of Non-Class I piping could prevent safe reactor shutdown or emergency core cooling, and redundant trains of engineered safeguards equipment were not coincidentally affected by flooding or spraying damage from postulated Non-Class I line failures.
The licensees calculation, CA-91-136, East Turbine Building Pipe Break Analysis, stated that a flood flow rate less than 928 gpm could be considered acceptable in the East Turbine Building (elevation 931') since this flow rate was within the capacity of the floor drain system and other drainage paths (e.g., under doors). The licensees calculation also stated that if the flood flow rate was more than the capacity of the drainage paths, then further evaluation would be required to determine if preventive action would be required based upon whether the flood could be detected and terminated ten minutes prior to the assumed failure of redundant essential equipment (MCC-142/143 and MCC-133). The drainage capacity was determined be 928 gpm based on the flow through the floor drains and under door clearances. The expected flow rate from the 2.5" firewater pipe was 872 gpm. Assuming that the loose materials that the inspectors identified were to block one or more of the drainage paths (for example, the flow under the hot shop door and/or the turbine building west corridor),then the drainage capacity potentially could have been less than the flow from the firewater pipe break. Because this condition met calculation CA-91-136's criteria for requiring further evaluation, licensee personnel informed the inspectors that a cause evaluation, CE013022, would be performed to evaluate the as-found condition of the East Turbine Building (elevation 931').
Analysis:
The inspectors determined that the failure to establish and accomplish procedures that were appropriate to the circumstances to ensure that flood protection equipment would remain available during an internal flooding event in order to protect safety-related equipment was a performance deficiency warranting a significance evaluation. The inspectors concluded that the finding was more than minor in accordance with Inspection Manual Chapter (IMC) 0612, Power Reactor Inspection Reports, Appendix B, Issue Disposition Screening, issued on May 19, 2005. The finding involved the attribute of protection against external factors (i.e., a seismic event causing an internal flooding hazard) and affected the mitigating systems objective of ensuring the availability of systems that respond to initiating events to prevent undesirable consequences. Because loose material had collected in the room and potentially could have had an adverse effect on the propagation of water through floor drains and door clearances during an internal flooding event, the housekeeping procedure did not ensure that safety-related equipment would be protected during an internal flooding event. If flood water had not been diverted through floor drains and door clearances, the water could have adversely affected two redundant divisions of safety-related 480Vac MCCs for Emergency Core Cooling System (ECCS) equipment.
The finding also affected the cross-cutting area of Problem Identification and Resolution because the licensee failed to take adequate corrective action when the NRC previously identified the same issue in the ECCS corner rooms in 2002 (Inspection Report 05000263/2002004). This issue is discussed in Section 4OA2 of this report.
The inspectors evaluated the finding using the SDP in accordance with IMC 0609, Significance Determination Process, dated May 19, 2005, because the finding was associated with the availability and reliability of a train of a mitigating system as discussed above. For the Phase 1 screening, the inspectors used the Seismic, Flooding, and Severe Weather Screening Criteria on page 5 of IMC 0609, Appendix A, 1 in order to answer Question 5 under the Mitigating Systems Cornerstone column. The inspectors determined that the finding involved the degradation of equipment or a function that was specifically designed to mitigate a flooding event.
Therefore, the inspectors answered yes to the first question of the screening criteria.
The inspectors determined that two or more trains of a multi-train safety system or function would not have been degraded during a seismic and internal flooding event based on the location of the firewater pipe and the loose materials. The East Turbine Building (elevation 931') contained 12 floor drains that were located throughout the room. The inspectors determined that some of the floor drains would not have been plugged by the loose material during an internal flooding event. Also, operator action could have been taken by opening the double doors to the Hot Shop to allow the flood waters to exit to the outside of the Turbine Building and by securing the source of water before MCC-133 was affected. The operators in the main control room would have received an alarm for a running fire pump if a break in the firewater pipe occurred.
Based on the licensee's calculation CA-91-136, licensee personnel estimated that it would have taken 109 minutes for the flood waters at the 911' elevation to rise to the level such that MCC-133 would have been adversely affected. The calculation also stated that operators could take actions to prevent damage to MCC-133 up to ten minutes before the time of the assumed damage to MCC-133. The inspectors determined that some of the drainage paths would have remained available, and although MCC-143 could have been rendered inoperable during an internal flooding event, the licensee would have had time (109 minutes - 10 minutes = 99 minutes) to prevent adverse affects to MCC-133. Therefore, the inspectors answered no to the second question of the screening criteria, and the finding screened to Green. The inspectors concluded the issue was of very low safety significance.
Enforcement:
The Division I and II essential 480Vac MCCs located on the 911' and 931' elevations of the East Turbine Building were safety-related and were subject to the requirements of 10 CFR 50, Appendix B. Criterion V of 10 CFR 50, Appendix B, stated, in part, that activities affecting quality shall be prescribed by documented procedures of a type appropriate to the circumstances and shall be accomplished in accordance with these procedures. Contrary to this requirement, the licensee failed to establish and implement safety-related procedures for controlling loose materials that could have adversely impacted flood protection equipment and therefore the safety-related MCCs during an internal flooding event. Licensee personnel entered this issue into their corrective action program as CAP040752 and established control of the loose material.
Because this violation was of very low safety significance and was entered into the corrective action program, this violation is being treated as an NCV, consistent with Section VI.A.1 of the NRC Enforcement Policy. (NCV 05000263/2005011-001)
1R17 Permanent Plant Modifications
a. Inspection Scope
From September 12 through 16, 2005, the inspectors reviewed six permanent plant modifications that had been installed in the plant during the last two years. The modifications were chosen based upon their effect on systems that had high probabilistic risk analysis (PRA) significance in the licensee's Individual Plant Evaluation (IPE) or high maintenance rule safety significance. The inspectors reviewed the modifications to verify that the completed design changes were in accordance with the specified design requirements and the licensing bases and to confirm that the changes did not affect any systems' safety function. Design and post-modification testing aspects were verified to ensure the functionality of the modification, its associated system, and any support systems. The inspectors also verified that the modifications performed did not place the plant in an increased risk configuration.
The inspectors also used applicable industry standards to evaluate acceptability of the modifications. The list of documents reviewed by the inspectors is included as an attachment to this report.
b. Findings
No findings of significance were identified.
OTHER ACTIVITIES (OA)
4OA2 Identification and Resolution of Problems
.1 Routine Review of Condition Reports
a. Inspection Scope
From September 12 through 16, 2005, the inspectors reviewed 21 Corrective Action Process documents (CAPs) that were written by licensee personnel to enter issues in the corrective action program. The inspectors reviewed these documents to verify an appropriate threshold for identifying issues and to evaluate the effectiveness of corrective actions related to permanent plant modifications and evaluations for changes, tests, or experiments issues. In addition, one CAP, written on issues identified during the inspection, was reviewed to verify adequate problem identification and incorporation of the problems into the corrective action system. The specific corrective action documents that were sampled and reviewed by the team are listed in the attachment to this report.
The finding described in Section 1R02 of this report was related to the cross-cutting area of problem identification and resolution. In 2002, the NRC previously identified the issue of not controlling loose debris in the ECCS corner rooms (Inspection Report 05000263/2002004). The licensees corrective action in response to the previously issued NCV of 10 CFR Appendix B, Criterion V was to update the housekeeping procedure to include loose material controls for several areas, including the East Turbine Building. This corrective action was inadequate because loose material had accumulated as a result of licensee personnel not implementing the corrective actions as described in the housekeeping procedure. Furthermore, although the activity of controlling loose material for internal flooding purposes affected equipment that was safety-related, the licensee did not establish safety-related procedures to implement this activity. Licensee personnel initiated CAP040752 and CE013022 to enter the issue into their corrective action program and perform a cause evaluation.
b. Findings
No findings of significance were identified.
OTHER ACTIVITIES
4OA6 Meetings
.1 Exit Meeting
The inspectors presented the inspection results to you and others of your staff, on September 16, 2005. Licensee personnel acknowledged the inspection results presented. Licensee personnel were asked to identify any documents, materials, or information provided during the inspection that were considered proprietary. No proprietary information was identified.
ATTACHMENT:
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee
- J. Conway, Site Vice President
- R. Baumer, Compliance Engineer
- J. Fields, Manager Regulatory Affairs
- J. Grubb, Engineering Director
- N. Haskell, Design Engineering Manager
- T. Hurrle, Configuration Management Supervisor
- R. Johnson, Closeout Analysis.
- B. Sawatzke, Plant Manager
- D. Neve, Regulatory Affairs Manager
- E. Weinkam, Regulatory Affairs Manager, Corporate
- A. Williams, Projects Manager
Nuclear Regulatory Commission
- D. Hills, Chief, Engineering Branch 1
- A.M. Stone, Chief, Engineering Branch 2
- S. Ray, Acting Senior Resident Inspector
ITEMS OPENED, CLOSED, AND DISCUSSED
Opened and Closed
- 05000263/2005011-01 NCV Failure to Protect Flood Protection Equipment (Section 1R02)
Discussed
None.