ULNRC-06414, Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-Conformances Identified in Response to Regulatory Issue Summary 2015-06, Tornado ...

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Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-Conformances Identified in Response to Regulatory Issue Summary 2015-06, Tornado ...
ML18082B083
Person / Time
Site: Callaway Ameren icon.png
Issue date: 03/23/2018
From: Wink R
Ameren Missouri, Union Electric Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
ULNRC-06414
Download: ML18082B083 (20)
v • d • e


Text

Ameren MISSOURI CaIlaa Phim March 23, 2018 ULNRC-06414 U.S. Nuclear Regulatory Commission Ann: Document Control Desk Washington. DC 20555-000 1 10 CFR 50. Appendix A. GDC 2 Ladies and Genttetnen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 tINION ELECTRIC Co.

RENEWED FACILITY OPERATING LICENSE NPf-30 REOUEST TO EXTEND ENFORCEMENT DISCRETION PROVIDED IN ENFORCEMENT GUIDANCE MEMORANDUM 15-002 FOR TORNADO-GENERATED MISSILE PROTECTION NON-CONFORMANCES IDENTIFIED IN RESPONSE TO REGULATORY ISSUE

SUMMARY

2015-06, TORNADO MISSILE PROTECTION

References:

1. NRC Regulatory Issue Summary 201 5-06. Tornado Missile Protection, dated June 10, 2015 (ADAMS Accession Number ML15020A419)
2. NRC memorandLim, 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 ML I 6355A286)

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)

Per Reference 1, the NRC issued Regulatory Issue Summary (RIS) 20 15-06, Tornado Missile Protection, to, in part, remind licensees of the need to conform to their plants current, site-specific licensing bases for tornado-generated missile protection.

P.O. Box 620 Fulton, MO 65251 AmerenMissouri.com

ULNRC-064 14 March 23, 2018 Page 2 o15 Per Reference 2, the NRC provided in Enforcement Guidance Memorandum (EGM) 1 5-002 guidance to exercise enforcement discretion when an operating power reactor licensee does not comply with a plants current site-specific licensing basis for tornado-generated missile protection. It was noted that 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. It was further noted that the enforcement discretion period would expire three years after issuance of RIS 2015-06, dated June 10, 2015, for plants with a higher tortiado missile risk (Group A Plants) and five years after RIS issuance for plants with a lower tornado missile risk (Group B Plants). The EGM categorized Callaway Plant as a Group A plant.

Per Reference 3. the NRC issued Revision I of EGM 15-002 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 caseby-case basis and remain in place until compliance is achieved.

In accordance with EGM 15-002, Revision 1, Union Electric Company (dba Ameren Missouri) hereby requests that the NRC extend the expiration date for the period of enforcement discretion in effect for Callaway Plant from June 10. 2018 to June 10, 2020.

Ameren Missouri has completed a comprehensive assessment for Callaway Plant and has identified non-conforming conditions (NCCs) regarding tornado missile trotection requirements that affect the operability of structures, systems or components addressed in the Callaway Plant Technical Specifications. A summary of the assessment methodology, scope and results is provided in the attachment to this letter. further, the non-conforming conditions have been documented in the Callaway Plant corrective action program in accordance with plant procedures. and all required notifications have been completed. as also discussed in the attachment.

Consistent with the guidance provided in NRC Interim Staff Guidance DSS-ISG-20J6-01 (Reference 4). initial and comprehensive compensatory measures have been implemented for the Catlaway NCCs, and these are described in the attachment as well. 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 maimer. These comprehensive compensatory measures will remain in-place until the non-conformances are resolved.

The requested enforcement discretion due date extension would provide Ameren Missouri sufficient time to address the non-conforming conditions and achieve compliance. Ameren Missouri has concluded that there is no undue risk associated with the requested extension.

Ameren Missouri respectfully requests NRC approval of the requested enforcement discretion date extension prior to June 10, 2018 (i.e., prior to the current expiration date).

ULNRC-064 14 March 23, 2018 Page 3 of 5 This letter does not contain new commitments.

If there are any questions, please contact Tom Elwood at 314-225-1905.

Sincerely, C. Wink Manager. Regulatory Affairs

/4%) L-/

JP K!

Attachment:

Justification for Request to Extend the Expiration Date for Enforcement Discretion Regarding Tornado Missile Protection Requirements for Callaway Plant

ULNRC-06414 March 23, 201$

Page 4 of 5 cc: Mr. Kriss M. Kennedy Regional Administrator U. S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington. TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. L. John Klos Project Manager. Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O$H4 Washington, DC 20555-0001

ULNRC-064 14 March 23, 2018 Page 5 of 5 Index and send hardcopy to QA F lie A160.0761 Hardcopy:

Certuec Corporation 6100 Western Place. Suite 1050 Fort Worth, TX 76107 (Certtec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Other Situations ULNRC Distribution:

F. M. Diva I. E. Herrmann S. P. Banker B. L. Cox R. C. Wink T. B. Elwood Corporate Communications NSRB Secretary STARS Regulatory Affairs Mr. .Jay Silberg (Pillsbury Winthrop Shaw Pittman LLP)

Missouri Public Service Commission

Attachment to ULNRC-064 14 Justification for Request to Extend the ExpiratioH Date for Enforcement Discretion Regarding Tornado Missile Ptotection Requirements for Callaway Plant (14 pages)

AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT

1. Introduction This attachment provides the justification for Union Electric (dba Ameren Missouri) to request extension of the expiration date for entorcement discretion regarding tornado missile protection requirements for Callaway Plant, Unit 1 (Callaway).

Per Reference 1, the NRC issued Regulatory Issue Summary (RIS) 2015-06, Tornado Missile Protection, to, in part, remind licensees of the need to conform to theirplants current, site-specific licensing bases for tornado-generated missile protection.

Per Reference 2, the NRC provided in Enforcement Guidance Memorandum (EGM) 15-002 guidance to exercise enforcement discretion when a licensee does not comply with a plants current site-specific licensing bases for tornado-generated missile protection. EGM 1 5-002 identified Callaway as a higher tornado missile risk site (Group A), resulting in an enforcement discretion expiration date of June 10, 2018.

Ameren Missouri completed a comprehensive tornado missile protection assessment for Callaway and has identified non-conforming conditions regarding tornado missile protection requirements.

Compensatory measures were implemented to address the non-conforming conditions, in accordance with regulatory guidance.

Ameren Missouri is reqLlesting an extension to the enforcement discretion expiration date to allow sufficient time to address the non-conforming conditions.

Ameren Missouri plans to submit a license amendment request (LAR) to request approval for use of the Tornado Missile Risk Evaluator (TMRE) methodology, currently under development by the industry, or another acceptable probabilistic methodology for evaluating the identified non-conformances. In the event the probabilistic methodology results in an unacceptable result or solution, select items may be resolved in a deterministic manner by implementation of plant modifications or refined, detailed structural analyses.

This request to extend the enforcement discretion period for Callaway was prepared in accordance with guidance in Appendix B of Revision 1 of Interim Staff Guidance DSS-ISG-2016-01 (Reference3).

2. RIS 2015-06 Assessment Methodology The methodology followed by Ameren Missouri for the Callaway tornado missile protection assessment that was performed in response to RIS 2015-06 included the following:

(1) document the current licensing basis (CLB) for tornados and tornado missile protection, (2) evaluate the sites conformance with the tornado missile protection CLB through a design review, document review and plant walkdowns, and document any non conforming conditions, and (3) resolve the non-conforming conditions within the Callaway corrective action program.

3. Summary of CLB for Tornado and Tornado Missile Protection Design The Callaway CLB for tornados and tornado missiles pertinent to the RIS 2015-06 assessment is described in Revision OL-22 of the Callaway Final Safety Analysis Report (FSAR) Standard Plant (SP),

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AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALIAWAY PLANT Sections 3.3.2 and 3.5,1.4, respectively, and mirrored in the FSAR Site Addendum (SA), Sections 3.3.2 and 3.5.2, respectively.

Scope for Tornado Missile Protection FSAR SP 3.5 states that adequate missile protection is provided to ensure that those portions of the essential structures, systems, or components whose failure would result in the failure of the integrity of the reactor coolant system, reduce the functioning to an unacceptable level of any plant feature required for safe shutdown, or lead to offsite radiological consequences are designed and constructed so as not to fail or cause such a failure in the event of a postulated credible missile impact.

ESAR SP 3.3 states in part that all standard plant seismic Category I structures which are required for safe shutdown, contain equipment required for safe shutdown, are required to protect reactor coolant system integrity, or which protect stored fuel assemblies are designed to withstand the effects of a tornado. Per FSAR SA Sections 3.3.2 and 3.3.2.1, the same tornado loadings and design parameters apply to both the standard plant and site-related (i.e., specific to Callaway) seismic Category I structures.

The standard plant and site-related tornado-resistant structures include the following:

  • Reactor building
  • Control building
  • Fuel building
  • Auxiliary building
  • Diesel generator building
  • Diesel fuel oil storage tank access vaults
  • Turbine building (for structural framing integrity only)
  • Communications corridor (for structural framing integrity only)
  • Independent Spent Fuel Storage Installation (ISESI)
  • RAM storage building (for structural framing integrity only)
  • ESWS Pipes, Electrical Duct Banks, Manholes, and ESWS Supply Lines Yard Vault

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AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT CLB for Tornado Protection Design The design basis tornado described in FSAR SP 3.3.2.1 hasa maximum windspeed of 360 miles per hour (mph) which consists of a maximum rotational speed of 290 mph at a radius of 150 feet combined with a maximum translational speed of 70 mph. A minimum translational speed of 5 mph was used to maximize the transit time of the tornado across exposed plant features. An atmospheric pressure drop of 3.0 pounds per square inch (psi) at a rate of 2.0 psi per second was also used.

The design basis tornado characteristics are in accordance with RG 1.76, Table 1, for Region I as shown in Figure 1 of RG 1.76.

As described in FSAR SP 3.3.2.2, all standard plant seismic Category I structures are designed to prevent venting, with the exception of the main steam tunnel (Area 5 of the auxiliary building above elevation 2026) and the fuel building. The main steam tunnel and the fuel building are vented to the atmosphere with the exterior walls and roofs designed to resist the full pressure differential (3.0 psi) due to the design basis tornado. The interior walls and slabs are designed to resist the differential pressures between compartments that occur as a result of venting the structure.

Additionally, per FSAR SA 3.3.2.2, all Callaway-specific seismic Category I structures except the UHS cooling tower, are designed to prevent venting. The UHS cooling tower is fully vented because it is open throughout from the air inlets to the air outlets.

CLB for Tornado Missile Protection Design FSAR SP Table 3.5-1 identifies the following CLB tornado missiles:

- A 4-inch by 12-inch by 12-foot long wood plank with a weight of 115 pounds and horizontal velocity of 272 feet per second (fps).

  • A steel pipe, 6 inches diameter, Schedule 40, 15 feet long with a weight of 286 pounds and a horizontal velocity of 170 fps.
  • A steel rod, 1-inch diameter, 3 feet long with a weight of 9 pounds and a horizontal velocity of 167 fps.
  • A utility pole, 13.5 inches diameter, 35 feet long with a weight of 1123 pounds and a horizontal velocity of 180 fps.
  • A steel pipe, 12 inches diameter, Schedule 40, 15 feet long with a weight of 749 pounds and a horizontal velocity of 154 fps.
  • An automobile, 16.4 feet by 6.6 feet by 4.3 feet with a weight of 3991 pounds and a horizontal velocity of 194 fps.

Per FSAR SP 3.5.1.4, vertical velocities of 70 percent of the indicated horizontal velocities are considered for all missiles, except the 1-inch-diameter steel rod which is critical for penetration and is assumed to have a vertical velocity equal to the horizontal velocity. Neither the automobile nor the utility pole need be considered for any portion of the structures greater than or equal to 30 feet above the highest ground elevation. The tornado missile spectrum is in accordance with Section 3.5.1.4 of NUREG-0800 Standard Review Plan, Revision 1, and the response to NRC Question Q430.38 in the FSAR SP.

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AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT

4. RIS 201 5-06 Assessment Scooe and Results:

The assessment included and was based on reviews and walkdowns of Callaway systems, structures and components designed to withstand the tornado missiles specified in the CLB. A number of non-conforming conditions, along with the affected systems, were identified during the design reviews and walkdowns, and they were promptly documented in the Callaway corrective action program.

Non-conformances That Do Not Require Enforcement Discretion The following are descriptions of deviations from the CLB that were identified but which resulted in a determination of Operable but non-conforming. For these, enforcement discretion is not required, and is therefore not being invoked in accordance with the guidance of Reference 4, Appendix A, Section 2.0. Previous licensee-identified and NRC-identified unresolved items are included in this list in accordance with Section 2.0, Consideration for Operable, but Nonconforming SSCs, in Appendix A, Acceptable Initial and Comprehensive Compensatory Measures, to Reference 3.

a. CR 201601462: Tornado Missile Protection Fuel Building 2000 Elevation Exterior doors of the Fuel Building, 2000 elevation, are not of tornado missile resistant design or construction, resulting in the potential for a design basis missile to impact interior concrete walls that do not comply with the specified missile barrier thickness listed in FSAR SP Table 3.5-2. However, the reduced wall thickness was demonstrated to be sufficiently thick to protect housed SSCs, based on qualifying tornado missile tests credited in ESAR. This condition represents a non-conformance with the licensing basis but not one that required entry into any Condition or Required Action in the Technical Specifications.
b. CR 201408345/201405508: Turbine-Driven Auxiliary Feedwater Pump Exhaust Pipe Tornado Analysis.

The capability of the turbine-driven auxiliary feedwater pump (TDAFWP) exhaust piping to withstand the design basis tornado missile was not demonstrated by structural analysis.

Subsequently, a structural calculation was performed that demonstrated the exhaust piping was sufficiently robust to withstand the missile impact without impairing the ability of the TDAFWP to perform its specified function. The non-conformance with General Design Criterion 2 requires a change to the site licensing basis for ultimate resolution (possibly as resolved per the TMRE or other probabilistic methodology to be employed for final resolution). This condition represents a non-conformance with the licensing basis but not one that required entry into any Condition or Required Action in the Technical Specifications.

C. CR 201704151: Ultimate Heat Sink Interior Wall Does Not Meet Specified Thickness The interior concrete wall that provides separation between trains of the ultimate heat sink cooling tower does not comply with the minimum thickness specified in FSAR Table 3.5-2. However, the reduced thickness of the wall was demonstrated to be sufficiently thick to protect housed SSCs based on tornado missile impact testing credited in the FSAR. This condition represents a non-conformance with the licensing basis but not one that required entry into any Condition or Required Action in the Technical Specifications.

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ATtACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALIAWAY PLANT

d. CR 201701064: Crimping of the Emergency Diesel Generator Vent Line The emergency diesel generator (EDG) crankcase ejector discharge lines are exposed on the exterior of the Diesel Generator Building. Each discharge lines is potentially subject to impact by a tornado missile which could result in crimping of the line and limit or eliminate the crankcase ejector vent path for the associated EDG. Drawing review and walkdowns confirmed an alternate vent path (i.e., through a loop seal in a tornado missile protected area in the interior of the building structure) was provided for each line. The function of the EDGs is not adversely impacted by this configuration; therefore, no entry into any Condition or Requited Action in the Technical Specification was required.
e. CR 201701264: Emergency Fuel Oil Challenged by Tornado Missiles The emergency fuel oil truck connection line extends through the exterior wall of the Diesel Generator Building where it is exposed to design basis tornado missiles. Impact to the exterior, exposed portion of the non-safety line was determined to have the potential to indirectly affect the integrity of connected safety related fuel oil transfer piping on the interior of the structure and thereby prevent delivery of diesel fuel to the EDGs. Upon discovery of this condition, the applicable Conditions and Required Actions of the Technical Specifications were entered, the Enforcement Discretion guidance was followed, and an eight-hour non-emergency notification (Event Number (EN) 52607) was made to the NRC on March 13, 2017. Subsequently, a structural analysis was performed that demonstrated the non-conforming piping configuration was capable of withstanding all design basis tornado missile impacts without preventing the emergency diesel fuel oil transfer piping from performing its specified design function. EN 52607 was retracted, and application of the Enforcement Discretion provisions was withdrawn on April 19, 2017. The non-conformance with General Design Criterion 2 requires a change to the site licensing basis for ultimate resolution (possibly as resolved per the TMRE or other probabilistic methodology to be employed tor final resolution).

Non-conformances That Require Enforcement Discretion The following are descriptions of deviations from the CLB that resulted in a determination of safe shutdown equipment being subject to impact from a design basis tornado missile and which resulted in entries into applicable Conditions and Required Actions of the Technical Specifications, thereby requiring application of the Enforcement Discretion that is allowed per Reference 3.

a. CR 201704176: Auxiliary Feedwater Pump Recirculation Lines Portions of the auxiliary feedwater pump recirculation lines to the condensate storage tank (CST) are housed in a structure not credited for tornado missile impact, thereby potentially exposing the lines to damage. Crimping of the recirculation lines could adversely impact the ability of the TDAFWP and both motor-driven auxiliary feedwatet pumps (MDAFWPs) to perform their specified function(s). The applicable Conditions and Required Actions of the Technical Specifications were entered, and the Enforcement Discretion guidance was followed.
b. CR 201704531: Main Steam Safeties and Atmospheric Steam Dumps Not Analyzed.

Portions of the discharge piping associated with the atmospheric steam dump valves (ASDs) and the main steam safety valves (MSSVs) extend beyond the tornado resistant building structure where they are subject to impact from design basis tornado missiles. These sections of the discharge piping had not been previously analyzed to demonstrate their ability to withstand the tornado missile Page 5

ATtACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT impact; therefore, the applicable Conditions and Requited Actions of the Technical Specifications wete entered, and the Enforcement Disctetion guidance was followed.

c. CR 201704906: Diesel Fuel Oil Piping Vent Vulnerable to Tornado Missile Impact The emergency fuel oil piping includes vents that are located on the exterior of the Diesel Generator Building, and ate thereby exposed to design basis tornado missiles. Blockage or crimping of the emergency fuel oil storage tank vents and the emergency fuel oil day tank vents could result in fuel starvation, thus preventing the EDGs from performing their intended design function. The applicable Conditions and Required Actions of the Technical Specifications were entered, and the Enforcement Discretion guidance was followed.
d. CR 201705851: Electrical Supply to Ultimate Heat Sink Fans Subject to Tornado Missiles The electrical power supplies to the safety-related ultimate heat sink cooling tower fan motors are subject to a design basis missile that could enter the cooling tower structure, pass through steel grating and ultimately impact the electrical cable trays or conduits. The applicable Conditions and Required Actions of the Technical Specifications were entered, and the Enforcement Discretion guidance was followed.
5. Initial Actions For the cases that are identified above, the following initial actions (as applicable) were taken in response to identification of a non-conforming tornado missile protection condition, in accordance with EGM 15-002, Rev. 1 and Interim Staff Guidance DSS-ISG-2016-01, Rev. 1:
a. The identified condition was entered into the Corrective Action Program.
b. For an identified condition that resulted in an Operable but non-conforming determination, the condition will be resolved through the Callaway Corrective Action Program in accordance with EGM 15-002, Rev. 1 and DSS-ISG-201 6-01, Rev. 1.
c. For an identified condition that resulted in an inoperable determination for safe shutdown SSCs, the Enforcement Discretion Guidance was applied.

U. For the first non-conforming condition that was determined to require entry into the Enforcement Discretion guidance and its allowances, the condition was reported by Ameren Missouri as an eight-hour notification on August 15, 2017 (EN 52905) under the following regulations:

10 CFR 50.72(b)(3)(ii)(B) 10 CFR 50.72(b)(3)(v)(A), (B) and (D)

e. The NRC resident inspector was notified upon entry and exit of the applicable Technical Specification Conditions and Required Actions.
f. Initial compensatory measures were completed per EGM 15-002, Rev. 1 and Interim Staff Guidance DSS-ISG-2016-01, Rev. 1. The following procedures for performing actions to respond to a tornado were verified to be current and readily deployable:

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AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT

  • Station Unit Threat Forced Outage Response Plan Procedure (APA-ZZ-00151)
  • Station Emergency Issue Response Procedure (APA-ZZ-00152)
  • Station Severe Weather Procedure, Tornado Watch and Tornado Warning Procedure (OTO-ZZ-00012, Attachments C and D)

Specifically, in the event of a Tornado Watch issued by the National Weather Service, the following actions are required to be taken:

  • Alarm is sounded and plant announcement alerts plant personnel.
  • Operations personnel are alerted via the Control Room radio system; the Outside Operator is requested to report indications of tornados.
  • Security personnel are requested to report indication of tornados.
  • lithe plant is operating and safe operation is in jeopardy or significant damage is imminent, the plant is to be shutdown.
  • If ongoing work activities have removed credited protective hazard barriers and the tornado is moving toward the plant, the barriers are to be restored.
  • If the containment equipment hatch missile shield is open during a refueling outage and the tornado is moving toward the plant, the missile shield is to be closed unless otherwise determined by Shift Manager.
  • Surveillance procedures that may result in the inoperability of any Engineered Safety Feature are to be stopped.
  • Any outside movement of radioactive material is to be stopped.
  • Any essential equipment out of service that may be restored prior to severe weather conditions approaching the site will be restored.
  • Shift Manager makes notifications, as necessary, in accordance with the Duty Manager and designated associated personnel.
  • Security and Operations verity closure of doors in accordance with a proceduralized checklist.
  • Missile shields are verified to be in place in accordance with a proceduralized checklist.
  • Cranes activities are secured.
  • Switchyatd items that may become airborne or missile hazards in high winds are properly stored or secured.
  • Items in outside areas that may become airborne or missile hazards in high winds are properly stored or secured.
2. Similarly, in the event of a Tornado Warning, the following additional items are required to be performed:
  • The Control Room missile door (DSK36042) is closed.
  • Tornado Warning is added to the Safety Monitor.
  • Personnel are pre-staged at the Radiation Protection Access Control Area or the Control Room to assist with damage assessment and initiation of restorative actions, as possible.

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AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT

g. Training associated with tornado response procedures was verified to be current.
h. SSCs determined to be vulnerable to tornado missile impact were added to the Equipment Out-of-Service Log (EOSL).
i. Station awareness of tornado missile vulnerabilities was heightened by inclusion of the issue on the Operations shift turnover log and discussion of the issue at the beginning of shift turnover.
j. Licensee Event Report (LER) 2017-002-00 (Reference 5) was submitted on October 13, 2017 in accordance with 10 CFR 50.73 due to Technical Specification-required equipment that did not meet CLB requirements for protection against tornado missiles.

The LER was supplemented (Reference 6) on Match 1, 2018.

6. LonQ-Term Comnensatorv Measures and Actions Implemented The guidance in DSS-ISG-201 6-01, Rev. 1, Appendix A, was followed in the establishment of longer-term, more comprehensive compensatory measures. In all cases of non-conformances resulting in the use of Enforcement Discretion, the long-term compensatory measures were implemented as soon as practical and less than 60 days after initial discovery. The long-term comprehensive measures included maintaining the initial comprehensive measures, and they met the threshold of either lessening the likelihood of tornado missile impact or providing for prompt recovery of SSC function from tornado missile effects. Additionally, the comprehensive measures represent a discernable change from the pie-discovery actions.

The following actions have been implemented as long-term comprehensive compensatory measures for the specific tornado missile non-conformances previously identified. The measures will remain in place until restoration of conformance with licensing-basis protection requirements.

Auxiliary Feedwater Pump Recirculation Lines Portions of the auxiliary feedwater pump recirculation lines are housed in the CST valve house which is not a tornado missile resistant structure. The valve house is constructed of cement masonry unit (CMU) walls and a built-up roofing system, neither of which is credited as a barrier against design basis tornado missiles. A separate non-safety recirculation line is associated with each of the three auxiliary feedwater pumps (one turbine-driven pump and two motor-driven pumps). Missile impact that results in crimping but not shearing the lines could have an adverse impact on maintaining the necessary minimum pump flow, potentially resulting in pump damage.

This vulnerability is limited, however, since some level of mitigation is provided by the valve house and since the recirculation flow path required for each pump is provided by one of three distinct (but closely spaced) pipes.

Comprehensive compensatory measures were incorporated into plant procedure OTO-ZZ-00012, Severe Weather, which directs opening valve ALVO21 8 to provide an alternate recirculation flow path to a tornado protected supply source (i.e., the hardened condensate storage tank (HCST)),

thereby preventing damage to the turbine-driven auxiliary feedwater pump should the normally aligned recirculation line be crimped by missile impact. The valve alignment is performed when there is a tornado watch or tornado warning issued for the local county. The valve is located in the Auxiliary Building, a tornado missile resistant structure, and is restored to its normal Page 8

AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT configuration following expiration of the watch or warning, in accordance with plant procedure ODP-ZZ-00004, Locked Component Control. A Night Order was issued to raise awareness of the site vulnerability to tornado-generated missiles.

Additionally, OTO-ZZ-00012, Attachment K, Severe Weather Impact Inspection Guidelines, added the specific requirement to inspect and determine the condition of the auxiliary feedwater recirculation piping in the CST valve house following severe weather that subjects plant SSCs to potential damage. This inspection requirement represents a discernible change from the previous inspection criteria that required inspection of all safety related structures, at the building level only.

These long-term comprehensive compensatory measures are in accordance with EGM 15-002 and Interim Staff Guidance DSS-ISG-2016-01, and will remain in place Lintil the non conformances are resolved.

MSSV Exhaust and ASD Silencers Portions of the discharge piping associated with both the ASDs and MSSVs extend beyond tornado resistant building structures where they are subject to impact from design basis tornado-generated missiles.

The affected ASD discharge piping is potentially vulnerable to tornado missiles that could enter the Auxiliary Building through exterior metal siding. In addition, a 13-foot tall discharge silencer is positioned on top of the Auxiliary Building that is potentially subject to direct impact by a tornado missile. No analysis has been performed to demonstrate the discharge piping or silencer would withstand the missile impact without affecting the ability of the ASD piping to perform its function.

Similarly, the MSSV discharge piping is potentially vulnerable to tornado missiles that could enter the Auxiliary Building through the exterior metal siding. The vulnerable MSSV discharge piping also includes 16-inch diameter piping that extends approximately 11 feet above the Auxiliary Building concrete roof. Each of the 4 loops of Main Steam piping are equipped with 5 MSSVs having two exhaust pipes per valve resulting in a total of 40 exhaust pipe stacks.

Due to the robust nature of the exhaust piping, the limited applicability of the most damaging design basis missiles based on the height of the building structure, and the number of individual targets that would have to be severely damaged, it is very unlikely that a combination of tornado-missile strikes on the potentially vulnerable piping or silencers would prevent the ASD or MSSV safety functions from being met. Two of the four ASDs are adequate to meet shutdown requirements (FSAR SP Table 10.3-3).

Comprehensive compensatory measures included revision of OTO-ZZ-00012, Attachment K, to add a requirement to visually inspect the MSSVs and ASD5 following severe weather that has the potential to cause damage to plant SSCs. This component-specific inspection requirement replaced the prior guidance to inspect the sites safety related structures on a building level. The focus and priority on the specific vulnerability will provide for prompt identification and expedited recovery. The procedural guidance includes prompt notification of Maintenance to expedite the repair process and includes guidance that pipe cutting tools are available in the Auxiliary Building tool room, a tornado missile protected location.

Also included in the procedure is a safety caution that alerts responding personnel of the possible presence of steam in Area 5 of the Auxiliary Building.

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AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT These long-term comprehensive compensatory measures are in accordance with EGM 15-002 and Interim Staff Guidance DSS-ISG-2016-01, and will remain in place Lintil the non conformances are resolved.

Emergency Diesel Fuel Oil Tank Vents The emergency diesel fuel oil piping includes exterior vents that are exposed to design basis tornado missiles, thereby jeopardizing the ability of the system to deliver fuel to EDGs. Blockage or crimping of the emergency fuel oil storage tank (TJEO1NB) vents and the emergency fuel oil day tank (T]EO2A/B) vents could result in fuel starvation, thus preventing the EDGs from performing their intended design function. The vents for the emergency fuel oil storage tank and day tank for each EDG train are located on the exterior of the Diesel Generator Building and thus exposed to postulated design basis tornado missiles. (Each EDG train is separately equipped with its own vent paths for that trains associated emergency fuel oil storage tank and day tank.) Damage to the vent assemblies impacts the delivery of diesel fuel only when crimping of the piping occurs.

Comprehensive compensatory measures included revision of OTO-ZZ-00012, Attachment K, to add a requirement to visually inspect the emergency diesel fuel oil storage tank vents and the emergency diesel generator day tank vents following severe weather that has the potential to cause damage to plant SSCs. This component-specific inspection requirement replaced the prior guidance to inspect the sites safety related structures on a building level. The focus and priority on the specific vulnerability will provide for prompt identification and expedited recovery.

Additionally, the procedural guidance provides direction to utilize instructions for establishing alternate vent paths per OTN-JE-00001, Emergency Fuel Oil Storage and Transfer System, Section 5.0. The alternate vent path is made available by removal of a pipe cap and opening an isolation valve which is located and accessible from the interior of the Emergency Diesel Generator Building, a tornado missile protected structure. This method of providing an alternate vent path is available for either train (or both trains) of emergency diesel fuel oil piping, as necessary.

These long-term comprehensive compensatory measures are in accordance with EGM 15-002 and Interim Staff Guidance DSS-ISG-2016-01, and will remain in place until the non conformances are resolved.

UHS Cooling Tower Electrical Comronents The electrical power supplies to the UHS cooling tower fan motors have been determined to be vulnerable to tornado missile impact, which has the potential to prevent the cooling tower fans from performing their intended function. The UHS cooling tower fans are located in a tornado missile protected concrete structure. The cooling tower fan and shroud is protected by a missile shield positioned above the fan thereby preventing a vertical missile from entering the opening in the structures roof and impacting the fan However, the smallest of design basis tornado missiles (i.e., the one-inch diameter rod) could enter the roof opening at an acute angle that would allow the missile to bypass the interior missile shield, pass through the steel grating adjacent to the missile shield and ultimately impact the electrical cable trays or conduits necessary for functioning of the cooling tower fan assembly. A very low occurrence frequency for such a condition or result may be assumed due to the precise direction/angle that would be required to reach the critical components. Furthermore, each redundant train is equipped with two fans, both of which would have to be disabled in order to significantly increase the risk that the train would fail to accomplish its safety function.

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AUACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT Comprehensive compensatory measures included revision of OTO-ZZ-00012, Attachment K, to add a requirement to visually inspect the UHS Cooling Tower fan rooms for damage to the fan motors or electrical supplies following severe weather that has the potential to cause damage to plant SSCs.

Prompt identification of the potential loss of critical equipment and an assessment of the extent of damage is critical to initiation of recovery efforts. This component-specific inspection requirement replaced the prior guidance to inspect the sites safety related structures on a building level. The focus and priority on the specific vulnerability will provide for prompt identification and expedited recovery.

These long-term comprehensive compensatory measures are in accordance with EGM 15-002 and Interim Staff Guidance DSS-ISG-201 6-01, and will remain in place until the non-conform ances are resolved.

7. Assessment of Long-Term Compensatory Measures Coincident with Other Onerator Actions The above comprehensive compensatory measures established to address the non-conforming conditions and other expected operator actions in response to severe weather and a subsequent loss of off-site power (LOOP) were collectively assessed. This assessment considered the timing and duration of the operator actions specified within the compensatory measures coincident with the other actions the operators may need to perform in response to a severe weather LOOP event.

The alignment of the auxiliary feedwater turbine-driven pump recirculation line by opening valve ALVO21 8 to provide an alternate flow path to a tornado protected source is a pre-emptive measure taken at the time of a tornado watch or warning declaration, and therefore has no impact on operator actions that may be necessary to respond to a severe wind event.

The prioritization of walkdowns of the MSSVs, ASDs, and UHS cooling tower fan electrical components following a severe weather event has minimal effect on other operator actions that may be needed. The prompt walkdown of the most susceptible SSCs from a tornado missile strike, as specified in the severe weather procedure (OTO-ZZ-00012), is not an additional burden, since the buildings that house the SSCs of primary concern were previously included in the post-event walkdown. The prioritized walkdown allows prompt damage assessment that will inform remedial actions that may mitigate the event and result in prompt initiation of recovery efforts.

Similarly, the post-severe weather walkdown and inspection of the emergency diesel fuel oil storage and day tank vents does not place a significant burden on operators. The remedial action taken, if necessary, to provide an alternate vent path is not a challenging or time consuming activity since it involves removal of a small pipe cap and opening of a valve. Additionally, the focused inspection of the exterior vents does not increase the overall scope of walkdowns previously required by the severe weather procedure; rather, the revision prioritizes the activities to assess the SSCs that have been determined to be the most vulnerable.

The operator actions credited as comprehensive compensatory measures in the operating procedure revisions are limited and were determined to have minimal impact on other operator actions that may be needed.

The assessment concluded that the implemented comprehensive compensatory measures, along with other beneficial actions in a severe weather LOOP event can be completed without putting unnecessary burden on the operators.

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ATTACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT

8. Plans for Permanent Resolution Ameten Missouri plans to submit a risk-informed LAR for the use of the TMRE methodology, currently in development by the industry, or other acceptable alternate methodology. The risk-informed methodology would be used to evaluate the identified non-conformances.

In the event that an acceptable risk-informed methodology is not available for use or does not yield suitable results to evaluate the identified non-conforming conditions, the option of performing plant modifications or detailed structural analysis would be pursued as necessary.

9. Basis and Reason for Extension Reauest In EGM 15-002, the NRC provided guidance on exercising enforcement discretion when an operating power reactor licensee does not comply with a plants current site-specific licensing basis for tornado-generated missile protection. The NRC is exercising 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. Theenforcement discretion period is specified to expire three years after issuance of RIS 2015-06, 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 15-002 identified Callaway as a plant of a higher tornado missile risk; therefore, its enforcement discretion period will expire on June 10, 2018.

Per Reference 4, the NRC issued Revision 1 of EGM 15-002, which states that licensees may request an extension to their enforcement discretion expiration date if proper justification is provided. This extension is to be granted on a case-by-case basis.

In accordance with EGM 15-002, Revision 1, and supplemental guidance in Interim Staff Guidance, DSS-ISG-201 6-01, Revision 1, Ameten Missouri is requesting an extension of the expiration date for enforcement discretion from June 10, 2018 to June 10, 2020.

There is no undue risk associated with this requested extension of the enforcement discretion period for Callaway. The identified non-conformances involve limited exposure of equipment to tornado missiles, and for many of the non-conformances, the equipment is partially protected, the missile spectrum is limited, or the approach path is narrow. 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-conformances discussed above. The compensatory actions implemented for the non-conformances 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-conformances are minimized until permanently resolved.

Additionally, a collective review was performed to confirm that the site operators can perform the comprehensive compensatory measures coincident with other actions they may need to perform in a severe weather LOOP event without pulling unnecessary burden on the operators. These compensatory measures would remain in place throughout the period of extended enforcement discretion until the non-conformances are resolved.

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ATTACHMENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT The TMRE methodology is being developed by the industry to evaluate tornado missile protection non-conforming conditions. [ARs for implementation of the TMRE methodology at three pilot sites have been submitted and are under review, with NRC approval of the pilot site LARs expected in 2018. Once the pilot site LARs have been approved and the NE! guidance document revised/approved, then other licensees with identified tornado missile protection non-conformances are expected to submit [ARs based on the approved pilot [ARs and associated NEI guidance document.

The tornado missile protection non-conformances identified at Callaway will require application of the TMRE methodology or another acceptable probabilistic methodology for evaluating the identified non-conformances, followed by preparation and submittal of a [AR to permanently resolve the non-conformances. In the event of unacceptable results, the installation of plant modifications or refined detailed structural analysis would be pursued. Given that NRC approval of the TMRE pilot site [ARs is not expected until sometime later in 2018, actions to resolve the non conformances at Callaway cannot be reasonably implemented in an orderly and cost-effective manner in the time remaining under the existing enforcement discretion period.

The requested enforcement discretion expiration date of June 10, 2020 would allow Ameren Missouri sufficient time to resolve the tornado missile protection non-confotmances and restore the Callaway site to compliance with its approved licensing basis. Ameren Missouri expects that probabilistic analysis will resolve all of the identified non-conformances. The requested enforcement discretion expiration date of June 10, 2020 would provide sufficient time for Ameren Missouri to perform a probabilistic analysis for the non-conformances and submit a [AR for resolution of the non-conformances. Ameten Missouri plans to submit the [AR that will resolve the non conformances in 2019, pending approval of the pilot plant [ARs and issuance of the final approved version of NEI Technical Report (NEI 17-02) Tornado Missile Risk Evaluator (TMRE) Industry Guidance Document.

The requested extension of the enforcement discretion allows Ameren Missouri time necessary to resolve any non-conformance that is not resolved by the TMRE methodology or other acceptable probabilistic methodology by the alternate means previously described.

10. References 1 NRC Regulatory Issue Summary 201 5-06, Tornado Missile Protection, dated June 10, 2015 (ADAMS Accession Number M[15020A419)
2. NRC memorandum, Enforcement Guidance Memorandum 15-002, Enforcement Discretion for Tornado Generated Missile Protection Non-Compliance, dated June 10, 2015 (ADAMS Accession Number M[1 5111 A269)
3. NRC Interim Staff Guidance, DSS-ISG-2016-01, Clarification of [icensee 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 M[1 71 28A344)

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AHACH MENT JUSTIFICATION FOR REQUEST TO EXTEND THE EXPIRATION DATE FOR ENFORCEMENT DISCRETION REGARDING TORNADO MISSILE PROTECTION REQUIREMENTS FOR CALLAWAY PLANT

4. 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)

5. License Event Report 2017-002-00, Inadequate Protection from Tornado Missiles Identified Due to Nonconforming Design, dated October 13, 2017 (ADAMS Accession Number ML17285A630)
6. Supplemental Licensee Event Report 2017-002-01, Tornado Missile Vulnerabilities Result in Condition Prohibited by Technical Specifications, dated March 1, 2018 Page 14
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