L-18-108, Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-Conformance Identified in Response to Regulatory Issue Summary 2015-06, Tornado Missile..

Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-Conformance Identified in Response to Regulatory Issue Summary 2015-06, Tornado Missile..

ML18102A103
Person / Time
Site:	Davis Besse
Issue date:	04/12/2018
From:	Bezilla M FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-18-108
Download: ML18102A103 (13)

Text

FENOC'

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FirstEnergy Nuclear Operating Company 5501 North State Route 2 Oak Harbor, Ohio 43449 Mark 8. Bezilla Vice President, Nuclear April 12, 2018 L-18-108 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Davis-Besse Nuclear Power Station, Unit 1 Docket Number 50-346, License Number NPF-3 10 CFR 50.72 Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-Conformance Identified in Response to Regulatory Issue Summary 2015-06, "Tornado Missile Protection"

REFERENCES:

1. Nuclear Regulatory Commission (NRC) Regulatory Issues Summary 2015-06, Tornado Missile Protection, dated June 10, 2015 (ADAMS Accession Number ML15020A419)

2. NRC Memorandum, Enforcement Guidance Memorandum 15-002, Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance, dated June 10, 2015 (ADAMS Accession Number ML15111A269)

3. NRC Memorandum, Enforcement Guidance Memorandum 15-002, Revision 1: Enforcement Discretion for Tornado-Generated Missile Protection Non-Compliance, dated February 7, 2017 (ADAMS Accession Number ML16355A286)

4. NRC Interim Staff Guidance DSS-ISG-2016-01, Clarification of Licensee Actions in Receipt of Enforcement Discretion Per Enforcement Guidance Memorandum EGM 15-002, "Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance," Revision 1, dated November 2017 (ADAMS Accession Number ML17128A344)

In Reference 1, the NRC issued Regulatory Issues Summary (RIS) 2015-06, "Tornado Missile Protection," to, in part, remind licensees of the need to conform with a plant's current, site-specific licensing basis for tornado-generated missile protection.

419-321-7676

Davis-Besse Nuclear Power Station, Unit 1 L-18-108 Page 2 In Reference 2, the NRC provided in Enforcement Guidance Memorandum (EGM) 2015-002 guidance to exercise enforcement discretion when an operating power reactor licensee does not comply with a plant's current site-specific licensing basis for tornado-generated missile protection. The NRC would exercise this enforcement discretion only if a licensee implements initial compensatory measures to provide additional protection, followed by more comprehensive, long-term compensatory measures implemented within 60 days of issue discovery. The enforcement discretion would expire three years after issuance of RIS 2015-06 (dated June 10, 2015) for plants of higher tornado missile risk (Group A Plants) and five years after RIS issuance for plants of a lower tornado missile risk (Group B Plants.) The EGM categorizes the Davis-Besse Nuclear Power Station as a Group A plant.

In Reference 3, the NRC issued Revision 1 of EGM 2015-002 to state that licensees may request an extension to their enforcement discretion expiration date if proper justification is provided. This extension would be granted on a case-by-case basis and would remain in place until compliance is achieved.

In accordance with the revised EGM 2015-002, Revision 1, FirstEnergy Nuclear Operating Company (FENOC) hereby requests that the NRC extend the expiration date for the period of enforcement discretion for the Davis-Besse Nuclear Power Station (DBNPS) from June 10, 2018, to December 31, 2018.

FENOC has completed a comprehensive assessment for the DBNPS and has identified a non-conforming condition (NCC) regarding tornado missile protection requirements that affect the operability of structures, systems or components addressed in the DBNPS Technical Specifications. A summary of the assessment methodology, scope, and results is provided in the attachment.

The non-conforming condition has been documented in the FENOC corrective action program in accordance with FENOC procedures, and all required notifications have been completed, as discussed in the attachment.

Consistent with the guidance provided in NRC Interim Staff Guidance DSS-ISG-2016-01 (Reference 4), initial and long-term compensatory measures have been implemented for the DBNPS NCCs, as described in the attachment. Additionally, a collective review of the comprehensive compensatory measures currently in place, including expected operator actions in response to severe weather and a subsequent loss of offsite power, has been performed to confirm that the site can perform these compensatory measures and operator actions in an effective manner.

These compensatory measures will remain in place until the non-conformance is resolved.

The requested enforcement discretion due date extension would provide FENOC sufficient time to address the non-conforming condition and achieve compliance.

Davis-Besse Nuclear Power Station, Unit 1 L-18-108 Page 3 FENOC has concluded that there is no undue risk associated with the requested extension.

FENOC requests NRC approval of this enforcement discretion date extension by May 21, 2018.

There are no regulatory commitments included in this submittal. If there are any questions or if additional information is required, please contact Mr. Thomas A. Lentz, Manager - Fleet Licensing, at (330) 315-6810.

Sincerely,

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Mark B. Bezilla

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Attachment:

Justification for Request to Extend the Expiration Date for Enforcement Discretion Regarding Tornado Missile Protection Requirements for the Davis-Besse Nuclear Power Station cc:

NRC Region Ill Administrator NRC Resident Inspector NRC Project Manager Utility Radiological Safety Board

Attachment L-18-108 Justification for Request to Extend the Expiration Date for Enforcement Discretion Regarding Tornado Missile Protection Requirements for the Davis-Besse Nuclear Power Station Page 1 of 10

1.

Introduction This attachment provides the justification for the FirstEnergy Nuclear Operating Company (FENOC) request to extend the expiration date for enforcement discretion regarding tornado missile protection requirements for the Davis-Besse Nuclear Power Station (DBNPS).

In Reference 1, the NRC issued Regulatory Issue Summary (RIS) 2015-06, "Tornado Missile Protection," to, in part, remind licensees of the need to conform with a plant's current, site-specific licensing basis for tornado-generated missile protection.

In Reference 2, The NRC provided in Enforcement Guidance Memorandum (EGM) 2015-002 guidance to exercise enforcement discretion when a licensee does not comply with a plant's current site-specific basis for tornado-generated missile protection. EGM 2015-002 identified the DBNPS as a higher tornado missile risk site (Group A), resulting in an enforcement discretion expiration date of June 10, 2018.

FENOC completed a comprehensive tornado missile protection assessment for the DBNPS and has identified a non-conforming condition regarding tornado missile protection requirements. Compensatory measures were implemented to address the non-conforming condition, in accordance with regulatory guidance.

FENOC is requesting an extension to the enforcement discretion expiration date for the DBNPS to allow sufficient time to address the non-conforming condition.

This request to extend enforcement discretion was prepared in accordance with guida_nce in Appendix B of Revision 1 of Interim Staff Guidance DSS-ISG-2016-01 (Reference 4).

2.

RIS 2015-06 Assessment Methodology The methodology followed by FENOC for the DBNPS assessment in response to RIS 2015-06 includes the following three objectives:

(1) document the DBNPS current licensing basis (CLB) for tornados and tornado missile protection,

Attachment L-18-108 Page 2 of 10 (2) evaluate the site's conformance with the tornado missile protection CLB through design review and plant walkdowns, and document any non-conforming conditions, and (3) resolve non-conforming conditions within the FENOC corrective action program.

3.

Summary of CLB for Tornado and Tornado Missile Protection Design The Davis-Besse Nuclear Power Station, Unit 1 (DBNPS) CLB for tornadoes and tornado missiles pertinent to the RIS 2015-06 assessment are described in Revision 31 of the DBNPS Updated Final Safety Analysis Report (UFSAR),

Sections 3.3.2 and 3.5, respectively.

CLB for Tornado Protection Design The DBNPS UFSAR describes tornado missile protection in Section 3.5, with specific reference to certain equipment in Sections 3.8.1.1.5, 3.8.2.2.4, 9.1, 9.2.1, 9.2.7, 9.2.9, and 9.5.4.2. As discussed in DBNPS UFSAR Section 3.3.2, the tornado design parameters are a maximum rotational velocity of 300 miles per hour (mph), a translational velocity of 60 mph, and a pressure drop of 3 pounds per square inch gauge (psig).

The DBNPS UFSAR states tornado design is necessary only for structures and systems required for safe and orderly shutdown of the reactor. UFSAR section 3.3.2.1 and Table 3.3-1 lists the structures and systems designed for wind pressure resulting from a hypothetical tornado and for the associated missile described in Section 3.3.2.1. These structures include the Shield Building, Auxiliary Building, Intake Structure, Valve Rooms number 1 and 2, Service Water tunnel, and specific electrical manholes. The systems protected include:

a. Auxiliary feedwater system

b. Service water system

c. Component cooling system

d. Decay heat removal system

e. Makeup pumps

f.

Emergency Core Cooling System room air cooling fans

g. Containment air coolers

h. Steam generators

i.

Pressurizer

j.

Auxiliary feed pump room vent fans

k. Boric acid addition system I.

Emergency diesel generators, air receivers, day tanks, and diesel vent fans

m. Diesel generator rooms vent fans

n. Service Water System

Attachment L-18-108 Page 3 of 10

o. Required Class 1 E AC and DC electrical substations, motor control centers, batteries, chargers, rectifiers, and associated panels.

CLB for Tornado Missile Protection Design DBNPS UFSAR Table 3.5-2, "Credible External Missiles," lists nine equivalent missiles:

1) 12-foot-long piece of wood 8 inches in diameter traveling end on with a velocity of 250 mph or 367 feet per second (fps)

2) 4000 pound automobile traveling through the air at 50 mph/73.5 fps and at not more than 25 feet above the ground.

3) 10-foot-long piece of pipe 3.5 inches outside diameter traveling end with a velocity of 100 mph/147 fps. Pipe inner diameter is 3 inches, schedule 40.

4) 4 inch by 12 inch wood plank 12 feet long, with a density of 50 pounds per cubic foot (lb/ft3) and a velocity of 279 fps

5) Utility pole 13.5 inches in diameter, 35 feet long with a density 43 lb/ft3 and a velocity of 182 fps

6) One-inch solid steel rod 3 feet long with a density of 490 lb/ft3 and a velocity of 192 fps

7) 6-inch schedule 40 pipe 15 feet long with a density of 490 lb/ft3 and a velocity of 162 fps

8) 12-inch schedule 40 pipe 15 feet long with a density of 490 lb/ft3 and a velocity of 153 fps

9) 3-inch schedule 40 pipe 15 feet long with a density of 490 lb/ft3 and a velocity of 192 fps The most critical missile that might be associated with a tornado from this list is the 35-foot utility pole, based on its potential kinetic energy.

4.

RIS 2015-06 Assessment Scope and Results The assessment included design reviews and walk downs of DBNPS Category 1 structures, which were designed to withstand the tornado missiles specified in the CLB.

The non-conforming condition and affected systems identified by FENOC during the design reviews and walkdowns were documented in the following condition report within the corrective action program:

CR-2017-07588, RIS 2015-06 Tornado Missile Protection for EOG Week Tank Vents."

The Emergency Diesel Generator (EOG) fuel oil storage tank vents were identified as not being adequately protected from potential tornado-generated

Attachment L-18-108 Page 4 of 10 missiles. In the event tornado-generated missiles were to strike the EOG storage tank vents, the missiles could completely crimp the vent and isolate the vent paths. While the transfer pumps would remain able to transfer fuel oil to the associated EOG day tank, the removal of liquid from the tanks would create a vacuum in the tank, which could affect pump performance and challenge the structural integrity of the tanks, rendering both EOGs inoperable.

5.

Initial Actions Along with notifying the NRC Resident Inspector, the following initial actions were taken in response to the identified non-conforming condition, in accordance with EGM 15-002 and Interim Staff Guidance OSS-ISG-2016-01.

_ a. The non-conforming condition was reported by FENOC as an eight-hour notification on July 20, 2017 (Event Number 52865) under the following regulations:

10 CFR 50. 72(b)(3)(ii)(B), "The nuclear power plant being in an unanalyzed condition that significantly degrades plant safety."

10 CFR 50.72(b)(3)(v), "A condition that could have prevented the fulfillment of the safety function of a system needed to: (A) shutdown the reactor and maintain it in a safe shutdown condition; (B) remove residual heat; (C) control the release of radioactive material; and (0) mitigate the consequences of an accident."

b. Operability determinations were completed and documented in the corrective action program. The non-conforming equipment was initially declared inoperable. Guidance in Revision 1 of EGM 15-002 (Reference 3) was used to declare the equipment operable but non-conforming and to implement enforcement discretion.

c. Initial compensatory measures were completed per EGM 15-002 and Interim Staff Guidance OSS-ISG-2016-01. The following procedures for performing actions to respond to a tornado are credited:

Station severe weather abnormal operating procedure (AOP)

Station emergency operating procedures (EOPs)

Station procedures for the use of FLEX equipment to attain and maintain shutdown conditions.

Additionally, to further satisfy these initial compensatory measures, a heightened awareness of the item described in Section 4 was communicated to the on-shift operators via a Standing Order for the actions contained in RA-EP-02810, "Tornado or High Winds." Section 4 items are also being maintained in

Attachment L-18-108 Page 5 of 10 the Shift Manager turnover notes. The immediate compensatory measures for the items in Section 4 are described below.

EOG Week Tank Vents FENOC reviewed Emergency Plan Off Normal Occurrence Procedure RA-EP-02810, "Tornado or High Winds," and concluded that the actions described in this procedure satisfy DSS-ISG-2016-01, Attachment A, requirements for initial compensatory measures to verify procedural guidance is in place for tornado watch, tornado warning, and tornado response. Operations Department licensed operator training was verified to be current on this procedure and the other EOP/AOP/SAMG procedures that could be required to address loss of the emergency diesel generators due to the inadequate missile shielding.

d. A Licensee Event Report (LER) was issued for the identified tornado missile protection issue.

LER 2017-001-00 (Reference 5) was submitted in accordance with 10 CFR 50.73 due to Technical Specification required equipment (EOG fuel oil storage tank vent piping) not meeting CLB requirements for protection against tornado missiles.

e. The information below describes DBNPS operating procedural guidance pertaining to the initial compensatory measures described in DSS-ISG-2016-01, Revision 1, Appendix A, Item 2.

Remove, relocate, or secure potential missiles In the event a tornado watch, tornado warning, severe thunderstorm watch, or severe thunderstorm warning is declared, the operators are directed by AOP RA-EP-02810, "Tornado or High Winds" to inspect the Protected Area and switchyard for potential missiles and to reduce potential missiles where practical. Material in the area in and around the switchyard, which includes the EOG fuel oil storage tanks, is evaluated for additional restraints or removal. Any identified missile hazards shall be relocated away from the switchyard, moved indoors, or securely immobilized by appropriate means.

Temporary equipment is relocated away from the switchyard or restrained.

From a work management/configuration control perspective, protect equipment important to maintaining safe shutdown conditions.

To protect equipment that is important to maintaining safe shutdown conditions, AOP RA-EP-02810, Tornado or High Winds" directs operators to inspect the site for potential missiles in the event potential severe weather. RA-EP-02810 also directs the operators to evaluate ongoing maintenance activities and expedite the restoration of important plant

Attachment L-18-108 Page 6 of 10 systems and components to service and to stop unnecessary activities such as fuel handling, underwater diving operations, etc.

Promptly complete or restore equipment from maintenance activities in progress on equipment important to maintaining safe shutdown conditions.

FENOC procedures require operators to evaluate equipment that is out of service to identify critical equipment to return to service. NOP-OP-1007, "Risk Management" states that when severe weather conditions, including tornado, are present or expected then risk management actions are taken.

Generation risk activities in progress should be terminated or completed based on reduced risk. Activities in progress that impact probabilistic risk assessment (PRA) risk should typically be completed. Activities scheduled but not in progress that impact PRA risk should be rescheduled to when severe weather conditions are not expected to be present.

Restore equipment important to maintaining safe shutdown conditions if undergoing maintenance or testing, if possible.

FENOC procedures NOP-OP-1007, "Risk Management" and RA-EP-02810, "Tornado or High Winds" state that if severe weather conditions, including tornado, are present or expected then risk management actions are taken.

Generation risk activities in progress should be terminated or restored based on reduced risk. Activities in progress that impact PRA risk should typically be completed. Activities scheduled but not in progress that impact PRA risk should be rescheduled to when severe weather conditions are not expected to be present.

Verify equipment is ready to use by visual inspection, surveillances and preventative maintenance are current, and review pending equipment maintenance requests.

The FENOC work scheduling process requires the plant configuration risk due to equipment removed from service for maintenance activities be assessed. In addition, surveillance tests and preventative maintenance completion are monitored and routinely reviewed to ensure that surveillance tests and preventative maintenance are performed within their prescribed intervals.

f.

The information below describes DBNPS operating procedural guidance pertaining to the initial compensatory measures described in DSS-ISG-2016-01, Revision 1, Appendix A, Item 3.

Attachment L-18-108 Page 7 of 10 Warning and protection strategies for site personnel.

In the event of a tornado warning, AOP RA-EP-02810, "Tornado or High Winds" requires operators to announce that a tornado warning is in effect.

In addition, notifications are made in facilities outside the protected area that a tornado warning is in effect.

Strategies for prompt damage assessment and initiation of restorative actions (pre-staging of equipment and plant staff at safe, strategic locations to promptly implement any necessary mitigative actions).

In the event a tornado impacts the site, procedure RA-EP-02810, "Tornado or High Winds" directs operators be dispatched to visually inspect for damage, initiate recovery actions, and perform a damage assessment.

Safety-related structures, systems and components are to be visually checked for damage, including impediments to accessibility of structures, breaches to plant components or systems, damage to and debris on transformers, and check of overhead lines. Additionally, determination of degraded safety system response or component response is done using control room indications and alarms.

During these walkdowns, particular attention is focused on the EOG Fuel Oil Storage Tanks, including the vents, to ensure a vent path is available to support the automatic fill of the EOG Day tanks from the Fuel Oil Storage Tanks.

6.

Long-Term Compensatory Measures and Actions Implemented and/or Planned As longer-term comprehensive compensatory measures, the following actions were taken as described:

An Operations Standing Order was issued to increase awareness and preparedness relative to the identified potential tornado missile vulnerabilities.

Training was verified to be current on procedures RA-EP-02810, "Tornado or High Winds," and DB-OP-02705, "Initial Assessment and FLEX Equipment Staging," for performing actions in response to a tornado, as well as procedure DB-OP-02521, "Loss of AC Power Sources, for performing actions in the event of a loss of power to the essential busses.

The applicable Zone Equipment Operator was specifically assigned the task of performing visual inspections for the EOG Fuel Oil Storage Tank vents in the event of a tornado per RA-EP-02810 and the steps necessary to remove the transfer pumps from service pending establishment of an alternate vent path for the tanks.

Attachment L-18-108 Page 8 of 10 These long-term compensatory measures are in accordance with EGM 15-002, Rev. 1 and Interim Staff Guidance DSS-ISG-2016-01 and will remain in place until the non-conformance is resolved.

7.

Assessment of Long-Term Compensatory Measures Coincident with Other Operator Actions The long-term compensatory measures ensure plant operators have the required training and procedural guidance to ensure that the plant can be safely shutdown.

Based on the enhanced procedural guidance, there is sufficient guidance available to successfully mitigate the consequences from a tornado missile event that could impact the vents of the DBNPS EOG Fuel Oil Storage Tanks.

Assuming an EOG Fuel Oil Storage Tank (FOST) is at the high-level pump stop and the EOG has not been operated, the EOG Day Tank can sustain over one hour of full power operation prior to the EOG Fuel Oil Transfer Pumps energizing automatically to transfer FOST capacity to the EOG Day Tank. The operators are instructed to inspect the FOST vents for damage within 30 minutes of a tornado event. If a FOST vent is crimped or damaged, actions are established lockout the affected transfer pump until the vent can be inspected and/or an alternative vent path implemented utilizing other connections available on the FOST. Without relying on the FOSTs for additional fuel, the EOG Day Tanks contain sufficient fuel for over twenty hours of full power EOG operation.

DB-OP-02521, "Loss of AC Power Sources," directs operators to start the Station Blackout Diesel Generator (SBODG) and energize the Class 1 E Electrical Susses in the event power is lost to either bus and the EDGs are not available. If either Class 1 E Electrical Bus remains de-energized and attempts to use the SBODG have failed, then procedure DB-OP-02700, "Station Blackout," would be entered and performed in parallel with FLEX Support Guidelines to address an Extended Loss of AC Power (ELAP). Employment of diverse and flexible strategies will ensure core cooling, Spent Fuel Pool Cooling, and Containment integrity are maintained.

8.

Plans for Permanent Resolution FENOC is installing a missile protected emergency vent on each of the DBNPS EOG Fuel Oil Storage Tanks. The enforcement discretion extension until December 31, 2018, is requested to ensure there is sufficient time to plan and execute this permanent resolution to eliminate the non-conformance.

Attachment L-18-108 Page 9 of 10

9.

Bases and Reason for Extension Request In EGM 2015-002 (Reference 2), the NRC provided guidance to exercise enforcement discretion when an operating power reactor licensee does not comply with a plant's current site-specific licensing basis for tornado-generated missile protection. The NRC would exercise this enforcement discretion only when a licensee implements initial compensatory measures to provide additional protection, followed by more comprehensive, long-term compensatory measures implemented within 60 days of issue discovery. The enforcement discretion would expire three years after issuance of RIS-2015-006, dated June 10, 2015, for plants of a higher tornado missile risk (Group A Plants), and five years after RIS issuance for plants of a lower tornado missile risk (Group B Plants). EGM 2015-002 identified the DBNPS as a plant of a higher tornado missile ris'k; therefore, its enforcement discretion would expire on June 10, 2018.

In Reference 3, the NRC issued Revision 1 of EGM 2015-002, which stated that licensees may request an extension to their enforcement discretion expiration date if proper justification is provided. The extension would be granted on a case-by-case basis.

In accordance with the revised EGM 15-002, FENOC is requesting an extension to the expiration date for enforcement discretion at DBNPS from June 10, 2018 to December 31, 2018.

There is no undue risk associated with this requested extension of the enforcement discretion due date. The identified non-conformance involves limited exposure of equipment to tornado missiles. In addition, tornado missile scenarios generally do not represent a significant safety concern because their risk is bounded by the initiating event frequency.

A comprehensive assessment of the site regarding tornado missile protection against the current licensing basis has been completed, revealing the non-conformance discussed previously. The compensatory actions implemented for the non-conformance are consistent with the guidance in EGM 15-002 and Interim Staff Guidance DSS-ISG-2016-01 and provide assurance that the consequences of the identified non-conformance are minimized until permanently resolved.

Additionally, a collective review was performed to confirm that the site operators can perform the long-term compensatory measures coincident with other actions that may need to be performed in a severe weather event without putting unnecessary burden on the operators. These compensatory measures would remain in-place throughout the period of extended enforcement discretion, until the non-conformance is resolved.

To address the tornado missile protection non-conformance identified at the DBNPS, FENOC is installing a missile protected emergency vent on each of the EOG Fuel Oil Storage Tanks. The installation was initially scheduled for

Attachment L-18-108 Page 10 of 10 completion within the original enforcement discretion time frame; however, unanticipated delays have occurred with procurement of key material. The requested enforcement discretion expiration date of December 31, 2018, would allow FENOC sufficient time to procure the necessary equipment and perform the plant modification to resolve the tornado missile protection non-conformance and restore the site to compliance*.

If conditions arise such that achieving tornado missile protection compliance at DBNPS within the requested extended period of enforcement discretion is not possible, the NRC would be promptly notified.

10. References

1. NRC Regulatory Issue Summary 2015-06, Tornado Missile Protection, dated June 10, 2015 (ADAMS Accession Number ML15020A419)

2. NRC Memorandum, Enforcement Guidance Memorandum 15-002, Enforcement Discretion for Tornado Generated Missile Protection Non-compliance, dated June 10, 2015 (ADAMS Accession Number ML15111A269)

3. NRC Memorandum, Enforcement Guidance Memorandum 15-002, Revision 1; Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance, dated February 7, 2017 (ADAMS Accession Number ML16355A286)

4. NRC Interim Staff Guidance, DSS-ISG-2016-01, "Clarification of Licensee Actions in Receipt of Enforcement Discretion Per Enforcement Guidance Memorandum EGM 15-002, Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance." Revision 1, dated November 2017 (ADAMS Accession Number ML17128A344)

5. Licensee Event Report 2017-001-00, Emergency Diesel Generator Fuel Oil Storage Tank Vents Not Adequately Protected from Tornado-Generated Missiles, dated September 18, 2017 (ADAMS Accession Number ML17268A138)