05000263/LER-2007-005, For Monticello Regarding Discovery of Appendix R - Non-Compliant Manual Actions During Review of NFPA 805
| ML072530296 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/30/2007 |
| From: | O'Connor T Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-MT-07-061 LER 07-005-00 | |
| Download: ML072530296 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(B) |
| 2632007005R00 - NRC Website | |
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NuC Committed to Nuclear Excellence*
Monticello Nuclear Generating Plant Operated by Nuclear Management Company, LLC August 30, 2007 L-MT-07-061 10 CFR Part 50.73 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Monticello Nuclear Generating Plant Docket No. 50-263 License No. DPR-22 LER 2007-005, "Discovery of Appendix R - Non-compliant Manual Actions during Review of NFPA 805" A Licensee Event Report (LER) for this occurrence is attached.
This letter contains no new commitments and no revisions to existing commitments.
/*-4 77 c9 Timothy J. O'Connor Site Vice President, Monticello Nuclear Generating Plant Nuclear Management Company, LLC Enclosure cc:
Administrator, Region III, USNRC Project Manager, Monticello, USNRC Resident Inspector, Monticello, USNRC 2807 West County Road 75
- Monticello, Minnesota 55362-9637 Telephone: 763-295-5151 e Fax: 763-295-1454
NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 3150-0104 EXPIRES 6-30-2007 (6-2004)
COMMISSION
, the NRC may not conduct or sponsor, and a digits/characters for each block) person is not required to respond to, the information collection.
FACILITY NAME (1)
DOCKET NUMBER (2)
PAGE (3)
Monticello Nuclear Generating Plant 05000263 1 of 4 TITLE (4)
Discovery of Appendix R - Non-compliant Manual Actions during Review of NFPA 805 EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
MO DAY YEAR YEAR SEQUENTIAL REV MO DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO 05000 FACILITY NAME DOCKET NUMBER 07 12 2007 2007 005 00 08 30 2007 05000 OPERATING 1
THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) (11)
MODE (9) 20.2201 (b) 20.2203(a)(3)(ii)
X 50.73(a)(2)(ii)(B) 50.73(a)(2)(ix)(A)
POWER 100 20.2201 (dl 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(x)
LEVEL (10) 20.2203(a)(1) 50.36(c)(1)(i)(A) 50.73(a)(2)(iv)(A) 73.71 (a)(4) 20.2203(a)(2)(i) 50.36(c)(1 )(ii)(A) 50.73(a)(2)(v)(A) 73.71 (a)(5) 20.2203(a)(2)(ii) 50.36(c)(2) 50.73(a)(2)(v)(B)
OTHER Specify in Abstract below or 20.2203(a)(2)(iii) 50.46(a)(3)(ii) 50.73(a)(2)(v)(C) in NRC Form 366A 20.2203(a)(2)(iv) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 20.2203(a)(2)(v) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(C) 50.73(a)(2)(viii)(A) 20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(B)
LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NUMBER (Include Area Code)
Ron Baumer j 763-295-1357 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX SUPPLEMENTAL REPORT EXPECTED (14)
EXPECTED MONTH DAY YEAR SUBMISSION YES (If yes, complete EXPECTED SUBMISSION DATE).
X NO DATE (15)U ABSTRACT During performance of NFPA-805, Transition Project Task SUP-I, 'Manual Action Compliance,' it was determined that manual operator actions credited in IX/1 2-A Lower 4KV Room and XlI/14-A Upper 4KV Room to achieve and maintain Appendix R hot safe shutdown are non-compliant. The manual actions provide supplemental ventilation to the.4KV rooms in order to assure continued operability of vital switchgear. These manual actions are specified in an Appendix R Section III.G.1/G.2 fire area; however, they do not meet the criteria for allowable manual actions specified in RIS 2006-10, 'Regulatory Expectations with Appendix R paragraph II.G.2 Operator Manual Actions.'
The cause of the event was prior to the issuance of RIS 2006-10, MNGP considered the manual actions to provide supplemental ventilation to the 4KV rooms acceptable. The RIS defined actions that the industry had considered acceptable, as non-compliant with Appendix R requirements and as a result MNGP's manual actions to provide supplemental ventilation to the 4KV rooms are not acceptable. The corrective action for this event is to evaluate the non-compliant manual actions as acceptable due to detailed fire modeling and/or risk assessment or to correct the non-compliant manual actions.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6)
PAGE (3)
SEQUENTIAL REVISION Monticello Nuclear Generating Plant 05000263 YEAR NUMBER NUMBER 2 of 4 2007 005 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
Description
During performance of NFPA-805, Transition Project Task SUP-l, 'Manual Action Compliance,' it was determined that manual operator actions credited in IX/1 2-A Lower 4KV Room [EA] and XlI/14-A Upper 4KV Room to achieve and maintain Appendix R hot safe shutdown are non-compliant. The manual actions provide supplemental ventilation to the 4KV rooms in order to assure continued operability of vital switchgear [SWGR]. The switchgear provides power to equipment needed to achieve and maintain hot safe shutdown. These manual actions are specified in an Appendix R Section Ill.G.1/G.2 fire area; however, they do not meet the criteria for allowable manual actions specified in RIS 2006-10, 'Regulatory Expectations with Appendix R paragraph II.G.2 Operator Manual Actions.' No system actuations occurred as part of this event. The ventilation system [VK] for the 4KV rooms is original plant design. This condition has existed since implementation of Appendix R.
The discovery of these manual actions was reported as an unanalyzed condition as defined by 10 CFR 50.72(b)(3)(ii)(B) and has been entered into the site's corrective action program. The compensatory measure for these areas is to perform the existing specified manual actions.
Event Analysis
A fire induced loss of off site power, coincident with ambient temperature of 107 0F or greater, may require supplemental ventilation for the upper and lower 4KV rooms within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> in order to ensure Appendix R safe shutdown capability. The requirement for supplemental cooling was identified in 1991 when the Monticello Nuclear Generating Plant (MNGP) performed testing to determine the impact of extremely hot environmental conditions on plant equipment.
Recent issuance of RIS 2006-10, "Regulatory Expectations with Appendix R Paragraph II.G.2 Operator Manual Actions" provided clarification of the regulatory expectations associated with the use of operator manual actions in II.G.1 and Ill.G.2 fire areas. This RIS defines actions that the industry had considered acceptable, as non-compliant with Appendix R requirements.
The manual actions necessary to provide temporary ventilation to the 4KV rooms are non-compliant actions as indicated by RIS 2006-10.
Because of the above, the event is reportable via a Licensee Event Report under 10 CFR 50.73(a)(2)(ii)(B) - an event or condition that resulted in an unanalyzed condition that significantly degraded plant safety.
The event is not classified as a safety system functional failure.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6 PAGE (3)
I SEQUENTIAL REVISION Monticello Nuclear Generating Plant 05000263 YEAR NUMBER NUMBER 3 of 4" 2007 005 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
Safety Significance
MNGP maintains administrative controls for the introduction of combustible materials and ignition sources to limit the probability of a fire. The 4KV rooms are provided with fire detection and temperature monitoring equipment. The manual actions, while non-compliant with RIS 2006-10, are proceduralized and provide assurance that hot safe shutdown can be achieved and maintained. Based on the administrative controls, fire detection, temperature monitoring, and the reasonable manual actions to supplement ventilation, the safety significance is considered low.
The safety significance of this event was reviewed by the Probabilistic Risk Assessment (PRA) department. The review considered the risk associated with the potential failure of a manual action that is currently credited to allow prolonged 4KV switchgear operation in the event of a fire that results in a loss of offsite power. This manual action involves the provision of temporary ventilation capability to the 4KV rooms to assure continued availability of vital switchgear.
The importance of credit given to manual actions intended to support critical switchgear operation in the event of a fire can be determined by considering the limited conditions under which failure of performance of these manual actions would result in fuel failure and potential subsequent offsite radiological release. These conditions must include all of the following:
" The occurrence of a fire initiator that results in a plant transient. This fire must be of sufficient magnitude and in a location that would result in an automatic reactor trip or conditions that would prompt the operations staff to manually shut down the reactor.
The fire must cause a complete loss of normal offsite power, including both the 1 R and 2R transformer supplies to bus 14, or must fail the power supply or equipment required to support cooling to the 4KV switchgear rooms. This equipment would include V-CH-27, V-MZ-1, V-EF-9, bus 14, LC-102, MCC-121, LC-108, or P105. The fire can not result in a station blackout as such an event would preclude the need for cooling in the 4KV switchgear rooms.
The fire event must occur at a time where ambient temperatures in the 4KV switchgear areas are unusually high (in excess of 107 IF).
Operations staff must fail to implement the proceduralized process that establishes temporary cooling to the 4KV switchgear room(s). Critical switchgear room temperatures above 104 IF will result in a control room alarm (Computer alarms V4K500 and V4K501). It is estimated that the operators will have at least 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to establish supplementary ventilation in the 4KV rooms.
" Equipment and procedures intended to provide long term core cooling in the event of a station blackout (SBO) must fail. RCIC manual operation or fire system injection to theU.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6)
PAGE (3)
SEQUENTIAL REVISION Monticello Nuclear Generating Plant 05000263 YEAR NUMBER NUMBER 4 of 4 2007 005 00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) reactor are proceduralized methods to provide makeup to the reactor in a long term SBO event.
In conclusion, the safety significance is considered to be low.
Cause
Prior to the issuance of RIS 2006-10, MNGP considered the manual actions to provide supplemental ventilation to the 4KV rooms acceptable. The RIS defined actions that the industry had considered acceptable, as non-compliant with Appendix R requirements and as a result MNGP's manual actions to provide supplemental ventilation to the 4KV rooms are not acceptable.
Corrective Action
The non-compliant manual actions have been documented in the MNGP corrective action program. Remediation of these conditions will be coincident with MNGP's transition to the risk informed, performance-based, fire protection approaches contained in NFPA 805. The NFPA 805 transition will either evaluate the non-compliant manual actions as acceptable due to detailed fire modeling and/or risk assessment or the non-compliant manual actions will be corrected via physical changes to the plant.
Failed Component Identification None
Previous Similar Events
A review of station events found no events that were considered to be related to this event.