ML17249A123

LER 17-003-00 for Oyster Creek Regarding Automatic Scram While Subcritical Due to Low Reactor Level

ML17249A123
Person / Time
Site:	Oyster Creek
Issue date:	08/31/2017
From:	Gillin M F Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-17-053 LER 17-003-00
Download: ML17249A123 (4)

Text

f Exelon Generation RA-17-053 August 31, 2017 U.S. Nuclear Regulatory Commission Attn: Document Control Desk or 0-881 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Oyster Creek Nuclear Generating Station Renewed Facility Operating License No. DPR-16 NRG Docket No. 50-219 Oyster Creek Route 9 South P.O. Box388 Forked River, NJ 08731 10 CFR 50.73

Subject:

Licensee Event Report (LER) 2017-003-00, "Automatic Scram while Subcritical due to Low Reactor Level." Enclosed is LER 2017-003-00 reporting the automatic reactor scram while subcritical due to low reactor water level, which occurred on July 3, 2017. This event did not affect the health and safety of the public or plant personnel. This event did not result in a safety system functional failure. There are no regulatory commitments made in this LER submittal. ' Should you have any questions concerning this report, please contact Gary Flesher, Regulatory Assurance Manager, at (609) 971-4232. Respectfully, Michael F. Gillin Plant Manager Oyster Creek Nuclear Generating Station

Enclosure:

NRG Form 366, LER 2017-003-00 cc: Administrator, NRG Region I NRC Senior Resident Inspector -Oyster Creek Nuclear Generating Station NRC Project Manager -Oyster Creek Nuclear Generating Station NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06-2016) Estimated burden per response to comply with this mandatory collection request 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. t>-'t.'RR£C(lt, Reported lessons learned are incorporated into the licensing process and fed back to industry. +;:, \ LICENSEE EVENT REPORT (LER) Send comments regarding burden estimate to the FOIA, Privacy and Information Collections ... l Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail (See Page 2 for required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory ......... Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a (See NUREG-1022, R.3 for instruction and guidance for completing this form means used to impose an information collection does not display a currently valid OMB control httQ://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3l) number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection. 1. FACILITY NAME 2. DOCKET NUMBER 3. PAGE Oyster Creek Nuclear Generating Station 05000219 1 OF 3 4. TITLE Automatic Scram while Subcriticai due to low Reactor level 5. EVENT DATE 6. LEA NUMBER 7. REPORT DATE 8. OTHER FACILITIES INVOLVED I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO. MONTH DAY YEAR N/A 05000 FACILITY NAME DOCKET NUMBER 07 03 2017 2017 -003 -00 08 31 2017 N/A 05000 9. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) D 20.2201 (b) D 20.2203(a)(3)(i) D 50.73(a)(2)(ii)(A) D 50. 73(a)(2)(viii)(A) N D 20.2201 (d) D 20.2203(a)(3)(ii) D 50. 73(a)(2)(ii)(B) D 50.73(a)(2)(viii)(B) D 20.2203(a)(1) D 20.2203(a)(4) D 5o.73(a)(2)(iii) D 50.73(a)(2)(ix)(A) D 20.2203(a)(2)(i) D 50.36(c)(1)(i)(A) 1:8:1 50. 73(a)(2)(iv)(A) D 50.73(a)(2)(x) 10. POWER LEVEL D 20.2203(a)(2)(iil D 50.36(c)(1)(ii)(A) D 50.73(a)(2)(v)(A) D 73.11(a)(4l D 20.2203(a)(2)(iiil D 5o.36(c)(2) D 50.73(a)(2)(v)(B) D 73.11(a)(5l D 20.2203(a)(2)(1v) D oo.4a(a)(3)(n> D 50.73(a)(2)(v)(C)

• D 1a.n(a)(1) 00 D 20.2203(a)(2)(v) D 50.73(a)(2)(i)(A) D 50.73(a)(2)(v)(D) D 73.n(a)(2)(i) D 20.2203(a)(2)(vi) D 50.73(a)(2)(i)(B) D 50.73(a)(2)(vii) D 73.n(a)(2)(ii) D 50. 73(a)(2)(i)(C) D OTHER Specify in Abstract below or in NRG Form 366A 12. LICENSEE CONTACT FOR THIS LEA LICENSEE CONTACT rELEPHONE NUMBER (Include Area Code) Gary Flesher, Regulatory Assurance Manager {609) 971-4232 13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT CAUSE SYSTEM COMPONENT MANU-REPORTABLE I'. CAUSE SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX A N/A N/A N/A N N/A N/A N/A N/A N/A 14. SUPPLEMENTAL REPORT EXPECTED 15.EXPECTED MONTH DAY YEAR DYES (If yes, complete 15. EXPECTED SUBMISSION DATE) 1:8:1 NO SUBMISSION DATE N/A N/A N/A ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) On July 3, 2017 at approximately 10:30 hours with the reactor subcritical after a manual scram, an automatic reactor scram occurred due to low Reactor Pressure Vessel (RPV) water level. Prior to this event, Main Control Room (MGR) Operators established reactor water letdown, reset the manual scram and were placing RPV water level control in automatic using a Low Flow Feedwater Regulator Valve (LFRV). Reactor pressure control was automatically being maintained with turbine bypass valves. A low reactor water level occurred when a bypass valve opened as expected to lower reactor pressure. Operations personnel had reset the scram signal without fully evaluating other plant conditions. Upon resetting the scram with reactor water level not yet stabilized, an automatic scram was received on low reactor water level. The automatic scram initiation signal occurred with the plant in a shutdown NRC FORM 366 (06-2016)

NRC FORM 366A (06*2016)) U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 LICENSEE EVENT REPORT (LER) CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr10221r3D Estimated burden per response to comply with this mandatory collection request 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently vaiid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection. 1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER Oyster Creek Nuclear Generating Station NARRATIVE Plant Conditions Prior To Event Event Date: Unit 1 Mode: July 3, 2017 Hot Shutdown Description of Event YEAR 05000219 2017 -Event Time: 10:30 hours ET Power Level: 0% SEQUENTIAL NUMBER 003 REV NO. -00 On July 3, 2017 at approximately 10:30 hours a subcritical automatic reactor scram was received while stabilizing plant parameters after a manual scram. The automatic scram was due to low RPV water level. Prior to this, MCR operators established reactor water letdown, reset the manual scram and were placing RPV water level control in automatic using a LFRV. Reactor pressure control was automatically being maintained with turbine bypass valves. A low reactor water level occurred when a bypass valve opened as expected to lower reactor pressure. Operators reset the scram signal without fully evaluating other plant conditions. By resetting the scram signal with water level not yet stabilized, an automatic scram was received on low reactor water level. Operator fundamentals and human performance tools were not properly utilized prior to resetting the scram. Operations personnel did not ensure plant parameters of pressure and level were stable prior to resetting the scram. An expected pressure transient resulted in an automatic scram due to RPV level dropping below the scram setpoint. Cause of Event MCR Operators did not confer with the Unit Supervisor their intended actions nor did they provide an update to other control room personnel prior to resetting the scram. Operations personnel did not perform a thorough review of all system conditions prior to peer checking the scram reset. Additionally, the procedure did not provide details of conditions to verify prior to resetting the scram. Analysis of the Event The personnel involved did not display distinct thought to understand the impact that the action would have with reactor water level control in its current state. The operators should have taken the time to understand that resetting the scram at that time was not the correct action. The operators were not fully engaged and did not think about the consequences of resetting the scram prior to reactor water level stabilization. Their behavior represents a gap as described in SOER 10-2, Engaged, Thinking Organizations. Assessment of Safety Consequences Following the automatic scram actuation all systems responded as expected; therefore, this event is of low safety significance. NRC FORM 366A (06-2016) Page _2_ of _3_

NRC FORM 366A (06-2016)) U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 LICENSEE EVENT REPORT (LER) CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nureqs/staff/sr1022lr31) Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and led back to industry. Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection. 1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER YEAR Oyster Creek Nuclear Generating Station 05000219 2017 -NARRATIVE Corrective Actions SEQUENTIAL NUMBER 003 REV NO. 00 1) The station revised the Abnormal Operating Procedures for MCR operators to verify plant conditions are stable prior to resetting the scram signal. 2) Reinforcement of the requirements and proper use of operator human performance fundamental tools through training and evaluations. 3) Reinforcement of teamwork in MCR operations during training scenarios. Previous Occurrences LER 2013-005-00 was submitted when Oyster Creek Nuclear Generating Station, while shut down, experienced an automatic reactor scram when operators placed the Mode Switch from Refuel to Shutdown. The actuation was a result of jumpers not installed as required by procedure to prevent a full scram for this Mode Switch change. Component Data Component N/A NRC FORM 366A (06-2016) IEEE 805 System ID N/A IEEE 803A Component N/A Page_3_ of _3_