05000315/LER-2020-001, Containment Closure Requirements Not Met During Refueling Operations
| ML20353A109 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 12/09/2020 |
| From: | Lies Q Indiana Michigan Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| AEP-NRC-2020-75 LER 2020-001-00 | |
| Download: ML20353A109 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3152020001R00 - NRC Website | |
text
AnlWl'CoolH>Y BOUNDLESS ENERGY" December 9, 2020 Docket No.: 50-315 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Donald C. Cook Nuclear Plant Unit 1 LICENSEE EVENT REPORT 315/2020-001-00 lndlana Michigan Power Cook Nuclear Plant One Cook Place Br1dgman, Ml 49106 md1anamicl11ganpower com AEP-NRC-2020-75 10 CFR 50.73 Unit 1 Containment Closure Requirements Not Met During Refueling Operations In accordance with 10 CFR 50. 73, Licensee Event Report (LER) System, Indiana Michigan Power Company, the licensee for Donald C. Cook Nuclear Plant Unit 1, is submitting as an enclosure to this letter the following report:
LER 315/2020-001-00: Unit 1 Containment Closure Requirements Not Met During Refueling Operations There are no commitments contained in this submittal.
Should you have any questions, please contact Mr. Michael K. Scarpello, Regulatory Affairs Director, at (269) 466-2649.
Sincerely, l~)G Site Vice President MBE/mll
Enclosure:
Licensee Event Report 315/2020-001-00: Unit 1 Containment Closure Requirements Not Met During Refueling Operations
U. S. Nuclear Regulatory Commission Page 2 c:
R. J. Ancona - MPSC EGLE - RMD/RPS J. B. Giessner - NRC Region Ill D. L. Hille - AEP Ft. Wayne NRC Resident Inspector R. M. Sistevaris - AEP Ft. Wayne S. P. Wall-NRC, Washington D.C.
A. J. Williamson -AEP Ft. Wayne AEP-NRC-2020-75
Enclosure to AEP-NRC-2020-75 Licensee Event Report 315/2020-001-00: Unit 1 Containment Closure Requirements Not Met During Refueling Operations
Abstract
On October 12, 2020, at 23:56, Operations was notified that the Unit 1 Containment 612 Elevation Personnel Airlock Assembly equalization valves had been removed by Maintenance personnel on October 2, 2020, and were not reinstalled until approximately 20:00 on October 12, 2020. While the valves were removed, the movement of irradiated fuel assemblies within Containment to support the Unit 1 Cycle 30 core reload occurred between October 4, 2020, at 16: 16 and October 6, 2020, at 14:44.
During this time when there was movement of irradiated fuel assemblies within Containment, a Containment Penetration (equalization valves) that provided direct access from the Containment atmosphere to the outside atmosphere was not closed by a manual or automatic isolation valve, blind flange, or equivalent as required by Technical Specification (TS) Limiting Condition for Operation (LCO) 3.9.3. TS LCO 3.9.3, Condition A, requires that the movement of irradiated fuel assemblies within Containment be suspended immediately when one or more Containment Penetrations are not in a required status. This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as an Operation or Condition Prohibited by TS because TS LCO 3.9.3, Condition A was not met from October 4, 2020, at 16:16 to October 6, 2020, at 14:44.
The cause of the event has been preliminarily determined to be lack of procedural guidance. Planned corrective actions include incorporating additional guidance into Operations procedures for Refueling Integrity and Containment Isolation.
EVENT DESCRIPTION
On October 12, 2020, at 23:56, Operations was notifie_d that the Unit 1 Containment [NH] 612 Elevation Personnel Airlock Assembly [AL] equalization valves M had been removed by Mechanical Maintenance (MTM) personnel on October 2, 2020,
_ and were not reinstalled until approximately 20:00 on October 12, 2020. At the time of discovery, Unit 1 was in Mode 5 with Containment Operability not required until -entry into Mode 4.
The equalization valves were removed by MTM on nlghtshift on October 2, 2020, as part of a scheduled work activity to perfonn the majority of the Containment 612 Elevation Personnel Airlock preventative maintenance (PM) activities associated with as-left Airlock Local Leak Rate Testing (Barrel Test). During performance of the PM activities, the decision was made to replace the equalization valve assemblies. Questions arose regarding the replacement of hardware associated with the valves and work was stopped. On October 3, 2020, the decision was made to reschedule the Airlock Barrel Test and associated support activities until after the completion of core reload activities. On October 4, 20W at 10.55, a Unit 1 Control Room Log entry documented that 1-0HP-4030-127-041, Refueling Integrity, Data Sheet 2, Containment Equipment Hatch and Personnel Airlock, was satisfactorily completed. This data sheet is required to be perfomied prior to movement of irradiated fuel within Containment to verify the stahis of penetrations associated with the Equipment Hatch and Airlock Assemblies, including the 612 Elevation Personnel Airlock Assembly, but does not include guidance to verify the status of the equalization valves.,
The movement of irradiated fuel assemblies Within Containment to support the Unit 1 Cycle 30 -core reload occurred between October 4, 2020, at 16:16 and October 6, 2020, at 14:44. During this time when there was movement of irradiated fuel assemblies within Containment, a Containment Penetration (equalization valves) that provided direct access from the Containment atmosphere to the outside atmosphere was not closed by a manual or automatic isolation valve, blind flange, or equivalent as required by Technical Speciflcatlon (TS) Limiting Condition for Operation (LCO) 3.9.3. TS LCO 3.9.3, Condition A, requires that the movement of irradiated fuel assemblies within Containment be suspended immediately when one or more Contai_nment Penetrations are not in a required status.
This event is reportable in accordance with 10 CFR 50. 73(a)(2)(1)(B) as an Operation or Condition Prohibited by TS because TS LCO 3.9.3, Condition A was not met from October 4, 2020, at 16:16 to October 6, 2020, at 14:44.
CAUSE OF THE EVENT
The cause of the event has been preliminarily determined to be lack of procedural guidance for verifying containment closure capability of the equalization valves in Operations procedures. An In depth Apparent Cause Evaluation (IACE) is rn progress at the time of this submittal. If any Jnfonnation regarding the ca1,.1se or corrective actions differs significantly from what is documented In this Licensee Event Report (LER), a supplement will be submitted after the conclusion of the IACE.
CORRECTIVE ACTIONS
At the time of discovery, the equalization valves had been re-installed and no additional prompt corrective actions were required.
Planned Corrective Actions to address the lack of procedural guidance include:
- 1.
Revising procedures 1-0HP-4030-127-041 and 2-OHP-4030-227-041, Refueling Integrity, to Include verification ofthe equalizing valves being installed and Intact
- 2.
Revising procedures 1-OHP-4030-114-010 and 2-0HP-4030-214-010, Containment Isolation, to include verification of the eaualizinQ valves beinQ installed and intact.
NRC FORM 386A (08-2020)
ASSESSMENT OF SAFETY CONSEQUENCES
NUCLEAR SAFETY 2020
- 001 00 There was no actual nuclear safety hazard resulting from the movement of fuel while Unit 1 Containment Closure Capability was not maintained.
INDUSTRIAL SAFETY There was no actual or potential industrial safety hazard resulting from the movement of fuel while Unit 1 Containment Closure Capability was not maintained.
RADIOLOGICAL SAFETY A function of Containment during refueling activities is to mitigate the radiological release and exposure to control room occupants and to the public.
Nuclear Safety Analysis personnel evaluated the condition of the Containment Airlock equalization valves being removed during the movement of Irradiated fuel to determine the impact on the Updated Final Safety Analysis Report (UFSAR) safety analysis. The Fuel Handling Accident (FHA) is the only Chapter 14 design basis accident that is both applicable during refueling activities and potentially impacted by the condition of the equalization valves. The FHA is discussed In UFSAR Section 14.2.1.5, Containment Building Accident, and Section 14.2.1.6, Radiological Consequence Analysis.
The Containment Isolation requirements described in UFSAR Section 14.2.1.5 were not met with the equalization valves removed during fuel movement. UFSAR Section 14.2.1.6 states that the radiological analysis meets the Regulatory Guide 1.183 and 10 CFR 50.67 criteria and that FHA radiological analysis does not credit Containment Isolation.
With Containment being incapable of isolation, mitigation of radiological release would be-impacted. However, the corresponding key radiological Regulatory Guide 1.183 and 10 CFR 50.67 acceptance criteria required by the UFSAR were not impacted. It was determined that the condition did not Impact the analytical consequences described in the UFSAR safety analysis and the required Regulatory Gulde 1.183 and 10 CFR 50.67 radiological criteria would have neither been exceeded nor had margin reduced if a FHA event had occ1,1rred during the time the equalization valves were removed.
PREVIOUS SIMILAR EVENTS
A review of LERs for the past five years found no events associated with the Containment Airlocks or the inability to establish Containment closure.
NRC FORM 368A (08-2020)