05000263/LER-1917-001, Regarding Reactor Scram and Group II Isolation Due to 11 Reactor Feed Pump (RFP) Removal from Service with 12 RFP Isolated
| ML17164A171 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 06/13/2017 |
| From: | Gardner P Northern States Power Company, Minnesota, Xcel Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-MT-17-049 LER 17-001-00 | |
| Download: ML17164A171 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 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)(iv)(B), System Actuation |
| 2631917001R00 - NRC Website | |
text
2807 West County Road 75 Monticello, MN 55362 800.895.4999 xcelenergy.com June 13, 2017 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket No. 50-263 (l Xcel Energy*
RESPONSIBLE BY NATURE L-MT-17-049 10 CFR 50.73 Renewed Facility Operating License No. DPR-22 LER 2017-001-00 "Reactor Scram and Group II Isolation Due to 11 Reactor Feed Pump (RFP)
Removal from Service with 12 RFP Isolated" Enclosed is the Monticello Nuclear Generating Plant (MNGP) Licensee Event Report (LER) 2017-001-00, "Reactor Scram and Group II Isolation Due to 11 Reactor Feed Pump (RFP)
Removal from Service with 12 RFP Isolated." This condition is reportable to the NRC in accordance with 10 CFR 50.73(a)(2)(iv)(A), as an event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph 10 CFR 50. 73(a)(2)(iv)(B),
specifically the Reactor Protection and Primary Containment Isolation Systems.
Summary of Commitments This letter makes no new commitments and no revisions to existing commitments.
1~ St<irt.a,. p, 6'-""tfi--t/
Peter AI. Gar ner Site Vice sident, Monticello Nuclear Generating Plant Northern States Power Company-Minnesota Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Monticello Nuclear Generating Plant, USNRC Resident Inspector, Monticello Nuclear Generating Plant, USNRC
NRC FORM 366 (04-2017)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
- 1. FACILITY NAME Monticello Nuclear Generating Plant
- 2. DOCKET NUMBER 05000 -263
- 3. PAGE 1 OF 3
- 4. TITLE Reactor Scram and Group II Isolation Due to 11 Reactor Feed Pump (RFP) Removal from Service with 12 RFP Isolated
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.
MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 05000 FACILITY NAME DOCKET NUMBER 04 15 2017 2017 - 001
- - 0 06 13 2017 05000
- 9. OPERATING MODE 3
- 10. POWER LEVEL 000
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(C) 73.77(a)(1) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a)(2)(i) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 73.77(a)(2)(ii) 50.73(a)(2)(i)(C)
OTHER Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT TELEPHONE NUMER (Include Area Code)
Rick Loeffler, Senior Licensing Engineer 763-295-1247 CAUSE SYSTEM COMPONENT MANU-FACTURER REPORTABLE TO EPIX
CAUSE
SYSTEM COMPONENT MANU-FACTURER REPORTABLE TO EPIX
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED SUBMISSION DATE MONTH DAY YEAR YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
NO ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On April 15, 2017 at 0436 hours0.00505 days <br />0.121 hours <br />7.208995e-4 weeks <br />1.65898e-4 months <br />, the 11 Reactor Feedwater Pump (RFP) was removed from service and the discharge valve closed. With the discharge valve closed and 12 RFP previously isolated no flow path was lined-up for the Condensate pumps to supply water to the vessel. Reactor water level lowered resulting in valid Reactor Protection System (RPS) actuation and Primary Containment Group II Isolation signals. The 11 RFP discharge valve was reopened to reestablish a flowpath to restore level. The RPS and Group II isolation logic was reset when cleared. Two apparent causes were identified: 1) Failure to identify and address the unusual Feedwater System configuration prior to execution of the 11 RFP shutdown. 2) Guidance for shutdown of the RFP did not take into account the state of the other train when shutting down a RFP. The corrective actions were: 1) Revise plant startup and shutdown procedures to ensure abnormal equipment lineups are addressed to avoid unexpected interactions. 2) Revise the Feedwater System operation procedure to maintain a flow path when the opposite train Reactor Feed Pump is isolated NRC FORM 366 (04-2017)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
EVENT DESCRIPTION
On April 10, 2017, at approximately 1140 hours0.0132 days <br />0.317 hours <br />0.00188 weeks <br />4.3377e-4 months <br />, prior to the 2017 Refueling Outage (RFO), the 12 Reactor Feedwater Pump (RFP) [EIIS: P] was removed from service and isolated for maintenance. On April 15, 2017, at 0142 hours0.00164 days <br />0.0394 hours <br />2.347884e-4 weeks <br />5.4031e-5 months <br />, a manual reactor scram was inserted to shutdown the plant for the 2017 RFO.
On April 15, 2017 at 0436 hours0.00505 days <br />0.121 hours <br />7.208995e-4 weeks <br />1.65898e-4 months <br />, with the unit in Mode 3, the 11 RFP in the Feedwater System [SJ] was removed from service in accordance with plant shutdown procedures and the 11 RFP discharge valve (FW-68-1) [ISV] was closed. With the 11 RFP discharge valve closed and the 12 RFP previously isolated, there was no make-up flow path lined-up for the Condensate pumps to supply water to the reactor vessel [RPV]. Reactor water level lowered, and at approximately 0441 hours0.0051 days <br />0.123 hours <br />7.291667e-4 weeks <br />1.678005e-4 months <br />, resulted in a valid Reactor Protection System (RPS) [JD] actuation (scram) signal and a valid Primary Containment Group II Isolation [JM] signal when level decreased below +9 inches as indicated on the Safeguards level instrumentation. The 11 RFP discharge valve was reopened to reestablish a flowpath from the Condensate pumps restoring reactor water level. The RPS and Group II isolation logic was reset at 0452 and 0500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br />, respectively, as stated in the station log. An eight hour event notification was made pursuant to 10 CFR 50.72(b)(3)(iv)(A). All systems functioned as required.
EVENT ANALYSIS
This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A), Any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph 10 CFR 50.73(a)(2)(iv)(B). Specifically, the RPS and the Primary Containment Isolation System (PCIS) actuations. This event is not classified as a safety system functional failure.
CAUSE
Two apparent causes were identified:
- 1. Operators failed to identify and address the unusual Condensate and Feedwater System configuration prior to execution of the 11 RFP shutdown.
- 2. The guidance for shutdown of the RFP in the Condensate and Reactor Feedwater System operation procedure did not take into account the state of the other train when shutting down a RFP.
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
Page 3 of 3 (04-2017)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER Monticello Nuclear Generating Plant 05000-263 YEAR SEQUENTIAL NUMBER REV NO.
2017 - 001
- - 0
SAFETY SIGNIFICANCE
The safety objective of both the RPS and PCIS are to provide timely protection at the onset of conditions that could challenge the integrity of the fuel barrier and nuclear system process barriers. The RPS prevents the release of radioactive material from the fuel and nuclear system process barriers by terminating excessive temperature and pressure increases through the initiation of an automatic plant shutdown. The reactor was subcritical with all rods inserted at the time of the actuation. PCIS prevents release of radioactive materials by isolating the reactor vessel and closing containment where required. The RPS, PCIS, and plant safety systems functioned as designed and fuel and nuclear system process barriers remained intact.
Consequently, this event did not have an adverse impact on the health and safety of the public.
CORRECTIVE ACTIONS
The immediate corrective actions were:
- 1. An Operations Memo was issued to reinforce operator fundamentals and performance expectations, and Operations management personnel were assigned to monitor the Control Room during major plant maneuvers throughout the remainder of the outage.
The long-term corrective actions are:
- 1. Revise the plant startup and shutdown procedures to ensure abnormal equipment lineups are addressed such that unexpected procedural interactions are avoided.
- 2. Revise the Condensate and Reactor Feedwater System operation procedure to maintain a flow path when the opposite train Reactor Feed Pump is isolated.
PREVIOUS SIMILAR EVENTS
There were no previous similar licensee event reports in the past three years.
ADDITIONAL INFORMATION
The Institute of Electrical and Electronics Engineer codes for equipment are denoted by [XX].
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)