Text

Response (90-Day) to Request for Additional Information Associated with License Amendment Request to Adopt National Fire Protection Association (NFPA) Standard 805
	ML15005A073
Person / Time
Site:	Robinson
Issue date:	12/22/2014
From:	Glover R; Duke Energy Carolinas
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	RNP-RA/14-0134
	Download: ML15005A073 (46)
	v • d • e

R. Michael Glover DUKE H. B. Robinson Steam Electric Plant Unit 2 Site Vice President Duke Energy Progress 3581 West Entrance Road Hartsville, SC 29550 DEC 2 2 2014 0:843857 1704 F: 843 857 1319 Mike. Gloi'er(a duke-energ,. corn Serial: RNP-RA/14-0134 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 / RENEWED LICENSE NO. DPR-23 RESPONSE (90-DAY) TO REQUEST FOR ADDITIONAL INFORMATION ASSOCIATED WITH LICENSE AMENDMENT REQUEST TO ADOPT NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) STANDARD 805

REFERENCES:

1. Letter from W. R. Gideon (Duke Energy Progress) to U. S. Nuclear Regulatory Commission (USNRC) (Serial: RNP-RA/1 3-0090), License Amendment Request (LAR) to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Generating Plants (2001 Edition), dated September 16, 2013, ADAMS Accession No. ML13267A211

2. Letter from Martha Barillas (USNRC) to Site Vice President, H. B. Robinson Steam Electric Plant (Duke Energy Progress), H. B. Robinson Steam Electric Plant, Unit 2 - Request for Additional Information on License Amendment Request to Adopt National Fire Protection Association Standard 805, Performance-Based Standard for Fire Protection (TAC No.

MF2746), dated October 23, 2014, ADAMS Accession No. ML14289A260

3. Letter from R. Michael Glover (Duke Energy Progress) to U. S. Nuclear Regulatory Commission (USNRC) (Serial: RNP-RA/14-0122), Response (60-Day) to Request for Additional Information Associated with License Amendment Request to Adopt National Fire Protection Association (NFPA) Standard 805, dated November 24, 2014

Dear Sir/Madam:

By letter dated September 16, 2013 (Reference 1) Duke Energy Progress, Inc. submitted a license amendment request to adopt a new risk-informed performance-based fire protection licensing basis for the H. B. Robinson Steam Electric Plant, Unit No. 2 (HBRSEP2).

During the week of September 22, 2014, the NRC conducted an audit at HBRSEP2 to support development of questions regarding the license amendment request. On October 23, 2014 the NRC provided a set of requests for additional information regarding the license amendment request (Reference 2). That letter divided the requests for additional information into 60-day, 90-day, and 120-day required responses. The Duke Energy Progress 60-Day responses were conveyed to the NRC Document Control Desk via letter from R. Michael Glover on November 24, 2014 (Reference 3). Enclosed as agreed are the Duke Energy Progress responses to the 90-day requests for A additional information.

U. S. Nuclear Regulatory Commission Serial: RNP-RA/14-0134 Page 2 Please address any comments or questions regarding this matter to Mr. Richard Hightower, Manager - Nuclear Regulatory Affairs at (843) 857-1329.

There are no new regulatory commitments made in this letter.

I declare under penalty of perjury that the foregoing is true and correct. Executed on December

-.".-, 2014.

Sincerely, R. Michael Glover Site Vice President RMG/jmw Enclosure cc: Mr. V. M. McCree, NRC, Region II Ms. Martha C. Barillas, NRC Project Manager, NRR NRC Resident Inspector, HBRSEP2 Ms. S. E. Jenkins, Manager, Infectious and Radioactive Waste Management Section (SC)

U. S. Nuclear Regulatory Commission to Serial: RNP-RA/14-0134 44 Pages (including this cover page)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING VOLUNTARY FIRE PROTECTION RISK INITIATIVE

REQUEST FOR ADDITIONAL INFORMATION VOLUNTARY FIRE PROTECTION RISK INITIATIVE DUKE ENERGY PROGRESS H. B ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 Fire Protection Engineering (FPE) RAI 02 NFPA 805, Section 3.4.3(b) requires that plant personnel who respond with the industrial fire brigade be trained for their responsibilities, potential hazards to be encountered, and interfacing with the industrial fire brigade. LAR Attachment A, Table B-i, Section 3.4.3(b) indicates that guidance for non-industrial fire brigade members is found in FP-001. The procedure defines the actions needed to be taken by personnel discovering a fire, security personnel actions, and duty health physics contact actions. Provide a more detailed description of the elements of this procedure and training that demonstrates compliance with the requirements for training on responsibilities, potential hazards to be encountered, and interfacing with the industrial fire brigade. Additionally, identify what element of compliance is being "clarified" in the LAR statement "complies with clarification."

Response

RNP has a dedicated fire brigade and does not have personnel responding who are not active fire brigade members. The clarification element which is being addressed is how a non-industrial fire brigade member is trained in the event a fire is discovered or indication/suspicion of a fire by plant personnel.

The following steps per Plant Operating manual FP-001 "Fire Emergency", should be taken; the event should be reported immediately to the Unit 2 Control Room and the following information should be given:

Your name and location of fire Nature of fire, materials involved (electrical, oil, contaminated material, etc.)

Severity of fire (smoldering, small blaze, room engulfed in flames, etc.)

The following detailed information is associated with the compliance statement "complies with clarification." When the fire has been reported to the Unit 2 Control Room, then a person who is knowledgeable in fire extinguisher use, may attempt to extinguish a NON-PLANT EQUIPMENT (i.e., trash can fire) related fire with an appropriate fire extinguisher. If the fire cannot be readily extinguished, then remain in the vicinity at a safe distance until arrival of the Fire Brigade and inform the Fire Brigade Incident Commander of the circumstances.

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FPE RAI 03 LAR Attachment A, Section 3.4.1(c) states that fire brigade members are plant operators and "qualifications of individuals in the fire protection organization are administratively controlled to ensure qualification of the individual commensurate with the position being held and activities being performed." NFPA 805 Section 3.4.1(c) requires that the fire brigade leader and at least two brigade members have sufficient training and knowledge of nuclear safety systems to understand the effects of fire and fire suppressants on nuclear safety performance criteria. In NRC Regulatory Guide (RG) 1.189, "Fire Protection for Nuclear Power Plants", Revision 2, September 2009 (ADAMS Accession No. ML092580550), Section 1.6.4.1 "Qualifications," the NRC staff acknowledged the following example for the fire brigade leader as sufficient:

The brigade leader should be competent to assess the potential safety consequences of a fire and advise control room personnel. Such competence by the brigade leader may be evidenced by possession of an operator's license or equivalent knowledge of plant systems.

Provide additional detail regarding the training provided to the fire brigade leader and brigade members that addresses their ability to assess the effects of fire and fire suppressants on NFPA 805 nuclear safety performance criteria. Include the justification for how the training meets NFPA 805 Section 3.4.1.

Response

RNP utilizes a fire brigade where during every shift the brigade leader and at least two brigade members shall have sufficient training and knowledge of nuclear safety systems to understand the effects of fire and fire suppressants on nuclear safety performance. This is consistent with NFPA 805 Chapter 3 (Section 3.4.1(c)) and procedure AD-EG-ALL-1530, Fire Brigade Training. Note that the information in NSD 112 as referenced in LAR Attachment A, Section 3.4.1(c) has been superseded by AD-EG-ALL-1530.

An equivalent knowledge of plant systems is provided for under procedure AD-EG-ALL-1530, Fire Brigade Training, Section 5.5, 5.6 and Attachment 3. Attachment 3 specifies the plant systems for either a PWR or BWR that represent the minimum plant knowledge for a Non-Licensed Operator (NLO) fire brigade member or leader to understand the effects of fire and fire suppressants on nuclear safety performance criteria (ref. NFPA 805 Section 3.4.1(c)). Specifics from AD-EG-ALL-1530 are as follows:

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5.5 Fire Brigade Leader Training

1.

The Fire Brigade Leader is required to complete:

Fire Brigade Leader training An in-plant fire drill as fire brigade team leader Fire Brigade Leader qualification

2.

In addition to the fire brigade member training and drill requirements (defined in this procedure), Fire Brigade Leader training should address and emphasize the following objectives:

Command structure Roles of Fire Brigade Leader and Fire Chief Command of a fire brigade - Concepts of Incident Command Incident Safety Officer Responsibility Organizational setup for emergency response Coordination of off-site fire company using ICS Managing resources Pre-Incident Information Communications Site Fire Brigade Standard Operating Guidelines Fire brigade checklist and drill review Firefighting survival, strategy, and tactics Site fire strategies Fighting of fires in RCAs and RCZs and potential Radioactive Material Releases Case studies of fire incidents (OE)

Fire Brigade Leader practical to include special problems with fire suppression and leadership 5.6 Safety Systems Training

1.

The FBL and at least two other members of the brigade shall have knowledge, training, and understand the effects of fire and fire suppressants on safe shutdown equipment. This training and knowledge may be satisfied by:

a.

Completing and maintaining a fire brigade qualification and meeting one of the following requirements:

(1) Be a licensed Senior Reactor Operator.

(2) Be a licensed Reactor Operator.

(3) Have successfully completed a reactor operator certification program.

(4) Have successfully completed training on the plant systems listed in Attachment 3, Fire Brigade Safety Systems Individual System Knowledge List.

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From Attachment 3:

Fire Brigade Safety Systems Individual System Knowledge List PWR BWR Reactor Coolant System Steam Generator System Auxiliary Feed System Charging and Volume Control System Residual Heat Removal System Safety Injection System Containment Spray System Component Cooling Water System Emergency Service Water System Electrical System Overview - AC & DC Emergency Core Cooling Systems 2035 - Core Spray System 2040 - Standby Liquid Control System 2045 - Residual Heat Removal System 2070 - Containment Atmosphere Control 2095 - High Pressure Coolant Injection 2100 - Reactor Core Isolation Cooling 4060 - Service Water System 4070 - Rx Bldg Closed Cooling Water 5095 - Diesel Generator System 5097 - Supplemental DG System 5098 - SAMG Diesel Generator System 5100 - Diesel Generator Fuel Oil System 5135 - 230KV Switchyard 5145 - SAT, UAT Transformer System 5170 - 4KV AC Distribution 5175 - 480V AC Distribution 5230 - 250V DC Distribution 6175 - Fire Protection System 6195 - Fire Protection C02 System 6205 - Halon Supply System 7071 - Standby Gas Treatment System 7110 - Fuel Pool Cooling System 8075 - Diesel Building HVAC 8185 - Reactor Building HVAC 8220 - Control Building HVAC 8232 - Service Water Building HVAC Page 5 of 44

FPE RAI 04 LAR Section 4.8.1 states that, "a summary of the NFPA 805 compliance basis and the required fire protection systems and features is provided in Attachment C." However, LAR Attachment C only identifies the required suppression and detection systems for a fire area. There appears to be no discussion or description of other fire protection features (e.g., Electrical Raceway Fire Barrier Systems (ERFBS), radiant shields, instamatic coatings, enhanced combustible controls, and transient limitations) that may be credited or required relative to the fire area analyses. Provide the fire protection features, by fire area, that are required by the Fire Probabilistic Risk Assessment (PRA), and their respective compliance bases.

Response

The response to FPE RAI 07, submitted with the 60 day responses, describes the use of Hemyc and MT ERFBS at RNP. The response to FPE RAI 13, submitted with the 60 day responses describes the physical barriers for fire delay in the Electrical Equipment Room and the Cable Spread Room. When these modifications are complete, the Fire Safety Analysis (FSA) for these areas will be updated to reflect the type of barrier credited for the 10 minute time delay assumed by PRA in each room. These are currently the only two areas where the FPRA credits other fire protection features.

A revised Attachment C will be provided with the 120 day responses.

FPE RAI 05 NFPA 805, Section 3.9.2 requires that automatic and manual water-based fire suppression systems be equipped with a water flow alarm. LAR Attachment A, Section 3.9.2 indicates that some automatic water-based fire suppression systems do not have water flow alarms. The LAR also states that these systems are not required to have water flow alarms per NFPA 13, "Standard for the Installation of Sprinkler Systems," which only requires water flow alarms to be provided on sprinkler systems having more than 20 sprinklers. In addition, Nuclear Energy Institute (NEI) 04-02, "Guidance for Implementing a Risk-Informed, Performance-Based Fire Protection Program Under 10 CFR 50.48(c)", Revision 2, (ADAMS Accession No. ML081130188), defines "complies with clarification" as an editorial issue and compliance should be explained in the compliance basis field.

The NRC staff does not consider the lack of water flow alarms an editorial issue. Provide a compliance strategy commensurate with the guidance of NEI 04-02 and provide a compliance strategy with a detailed justification relative to NFPA 805 Section 3.9.2.

Response

The compliance strategy "Complies with Clarification" has been revised to "Complies via Engineering Evaluation", which is sufficient to meet the requirements of National Fire Protection Association (NFPA) 805 Section 3.9.2.

COMPLIES VIA ENGINEERING EVALUATION: Several of the automatic water-based fire suppression systems do not have water flow alarms. These systems have less than 20 sprinklers and are not required to have water flow alarms. Per RNP-M/BMRK-1009, "Code Compliance Evaluation NFPA 13 - Standard for Installation for Sprinkler Systems", and RNP-M/BMRK-1011, "Code Compliance Evaluation NFPA 15 -

Water Spray Fixed Systems", all requirements from NFPA 13 and NFPA 15 for water flow alarms are met.

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A revision to License Amendment Request (LAR) Attachment A, Table B-i, Section 3.9.2, to include this update, will be submitted with the 120-day Request for Additional Information (RAI) responses.

FPE RAI 06 NFPA 805, Section 3.9.4 requires that the diesel-driven fire pumps shall be protected by automatic sprinklers. LAR Attachment A, Table B-1 indicates that the diesel-driven fire pump is located outdoors and is separated from other important equipment, and therefore "complies with clarification." NEI 04-02 defines "complies with clarification" as an editorial issue and compliance should be explained in the compliance basis field.

The NRC staff does not consider the lack of automatic sprinklers for the diesel fire pump an editorial issue. Provide a compliance strategy and detailed justification commensurate with the guidance in NEI 04-02 and relative to NFPA 805, Section 3.9.4.

Response

The compliance strategy "Complies with Clarification" has been revised to "Complies via Engineering Evaluation" which is sufficient to meet the requirements of National Fire Protection Association (NFPA) 805 Section 3.9.4.

COMPLIES VIA ENGINEERING EVALUATION: The diesel-driven fire pump is installed outdoors at the Intake Structure on Lake Robinson. Per RNP-M/BMRK-1012, "Code Compliance Evaluation NFPA 20-Centrifugal Fire Pumps", all requirements from NFPA 20-1978, for outdoor diesel-driven fire pumps, are met.

A revision to License Amendment Request (LAR) Attachment A, Table B-i, Section 3.9.4, to include this clarification, will be submitted with the 120-day Request for Additional Information (RAI) responses.

FPE RAI 08 LAR Attachment K identifies an existing approved Appendix R exemption that is being transitioned for the installation of fixed fire suppression in the pump bays in lieu of a reactor coolant pump (RCP) lube oil collection system. This exemption credits the installed fire detection system, dikes to contain oil spills, and the containment spray system as a backup fire suppression system.

However, the dikes and the containment spray system are not identified in the LAR Attachment C, Table B-3 as fire protection features or systems credited for this fire area. Provide justification for not including these fire protection features in LAR Attachment C, Table B-3.

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Response

As noted in LAR Attachment K, these features are prior exemptions to Appendix R in lieu that a reactor coolant pump lube oil collection system is not provided. The dikes and Containment Spray System should have been included in the LAR Attachment C, Table B-3 and credited for this fire area as they are considered as required fire protection systems/features by NFPA 805 Chapter 3 and the RNP FP program.

A revision to LAR Attachment C, Table B-3, to include these systems as required fire protection system/feature, will be submitted with the 120-day RAI responses.

FPE RAI 14 NFPA 805, Section 3.4.4, "Fire-Fighting Equipment," requires that equipment shall conform to the applicable NFPA standards. LAR Attachment A, Section 3.4.4, "Fire Fighting Equipment" states that the licensee has not committed to following any NFPA standards pertaining to firefighting equipment.

Describe what types of requirements or standards will be established when purchasing replacement protective clothing, hoses, nozzles, fire extinguishers and other equipment for the fire brigade use in order to ensure suitable products are procured. Include a discussion of whether manufacturers' guidelines will be followed, how the licensee intends to ensure the integrity of its equipment over time, and what type of replacement criteria are in place to ensure the equipment remains in good working order.

Response

As noted in LAR Attachment "A" HBRSEP intends to satisfy NFPA 805, Section 3.4.4 in terms of applicability as described in NEI 04-02 Rev 2, and FAQ 06-0020. Where used in NFPA 805, Chapter 3, the term, "applicable NFPA Standards" is considered to be equivalent to those NFPA standards identified in the current license basis (CLB) for procedures and systems in the Fire Protection Program that are transitioning to NFPA 805."

LAR Attachment "A" will be revised to include the following clarification, HBRSEP makes use of Duke Energy fleet procedure AD-EG-ALL-1531, Selection, Care and Maintenance of Fire Fighting Ensembles which follows the guidance found in NFPA standards associated with firefighting Personal Protective Equipment. Standards and requirements associated with installed fire protection equipment such as hoses, nozzles, fire extinguishers and other equipment are maintained in accordance with NFPA standards as described elsewhere in Chapter 3 and evaluated for compliance under the various NFPA Code Compliance Calculations listed for those sections of Chapter 3.

A revised Attachment A will be submitted with the 120 day responses.

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FPE RAI 15 LAR Attachment L, Approval Request #3 identifies other non-fire uses of the fire protection system and makes the statement that these have "no adverse impact on the ability of the fire protection system to provide required flow and pressure." Provide more detail to justify that the listed non-fire uses of fire protection water will not impair the ability to deliver the required fire water demand as required by NFPA 805, Section 3.5.16. Include in the response:

a)

Whether any uses are considered to be routine, "non-emergency," or "non-abnormal" operations.

b)

Describe any engineering controls, alarms and indications, and training that supports "no adverse impact" statement.

c)

Describe any of these operations that may be simultaneously in conjunction with the largest fire demand performed or conducted at the expense of the availability of the fire protection water system during the duration of alternative use. Include the largest design demand conditions required for the fire protection water systems. For instance, state whether the fire protection system is relied upon for any of these conditions.

d)

Describe the administrative controls, limitations, allowances, procedures, compensatory actions, dedicated communications, equipment, and work control practices that are in place to preclude interference with the ability of the fire protection systems to meet demand.

Response

a)

It is not routine to use fire water outside of emergent or abnormal operating procedure. The use of fire protection water for non-fire protection plant evolutions is an occurrence that requires Shift Manager review and concurrence, Per OMM-002, Section 8.15.2.4.

b)

As stipulated in OMM-002, Section 8.15.2.4, when fire water use is deemed necessary sufficient justification must be provided to show that the use of the fire water system for the activity does not cause the fire water system to be in a condition outside of the design basis such that the quantity of water does not exceed the supply and pressure requirements in the UFSAR. In the unlikely event fire water is used for a non-fire protection purpose without notification or concurrence from the Shift Manager, the Control Room will get an alarm indicating that the Motor Driven Fire Water Pump has started. An immediate investigation is initiated to determine the unapproved source is in use.

When a need to use fire water is identified, Robinson Engineering Support (RES) Fire Protection Engineering is requested to review the activity in addition to the Shift Manager's final permission. Stipulations are provided to ensure that flow rates for the requested job are not exceeded.

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Examples are as follows:

Maximum flow rates allowed are restricted and approved by RES Engineering and the Shift Manager.

ii.

Operations are to be contacted prior to each use.

iii.

Manipulations of valves are to only be completed by Plant Operations or a Plant Fire Brigade Member.

iv.

While the fire water is being used, personnel must be in constant attendance to immediately cease the use of water in the event of a plant fire alarm or at the request of Operations.

c)

The basis for determining the acceptability of a temporary non-fire protection related fire water use is the Updated Final Safety Analysis Report (UFSAR) Section 9.5.1 which specifies the minimum pressure in the plant loop with the largest deluge system in operation including fire hose demand. If a fire alarm is received during the use of the fire water system outside of emergency use, stipulations are provided to cease the use of the fire water system per Operations and RES Engineering. This is strictly adhered to ensure the quantity of water does not drop the supply pressure below the defined limits in the UFSAR, Section 9.5.1.

Since the fire water system is prohibited by procedure for routine usage not related to fire protection plant evolutions, it is not relied upon for any conditions other than fire suppression and emergent or abnormal procedures.

d)

Administrative controls are built into the request on a case by case basis as indicated in the examples in b. above. As previously stated, if a fire alarm is received during the use of the fire water system outside of emergency use, stipulations are provided to cease the use of the fire water system per Operations and RES Engineering. This is strictly adhered to ensure the quantity of water does not drop the supply pressure below the defined limits in UFSAR, Section 9.5.1.

Safe Shutdown Analysis (SSA) Request for Additional Information (RAI) 02 In LAR Attachment G, Table G-1, for Fire Areas AS and C, the staff noted that a DID recovery action may be required to provide portable fans for cooling the Control Room (CR). LAR Attachment G, Table G-1 identifies procedures (DSP-001 and EPP-001) for setup of the portable 4 kW generator and blowers used for this recovery action.

The requirements of General Design Criterion 3 (GDC-3) state for fire protection that structures, systems, and components (SSCs) important to safety shall be designed and located to minimize, consistent with other safety requirements, the probability and effect of fires and explosions. Noncombustible and heat resistant materials shall be used wherever practical throughout the unit, particularly in locations such as the containment and CR. Fire detection and fighting systems of appropriate capacity and capability shall be provided and designed to minimize the adverse effects of Page 10 of 44

fires on SSCs important to safety. Firefighting systems shall be designed to assure that their rupture or inadvertent operation does not significantly impair the safety capability of these SSCs.

The use of fuel-fired generators near the CR does not align with GDC-3. The use and refueling of portable generators presents a hazard to equipment important to nuclear safety. Describe and justify how the use of portable fuel-fired equipment is consistent with the requirements of GDC-3 or provide an approach to resolving the subject variances from deterministic requirements (VFDRs) and providing CR ventilation that is consistent with the requirements of GDC-3.

Response

The equipment associated with providing temporary cooling for the Main Control Room consists of a small generator, twenty inch smoke ejector/fan, (2) twenty foot duct sections, and (2) fifty foot extension cords. The equipment is located on the Turbine Building Mezzanine Level in a metal storage cabinet. When the equipment is used to provide temporary cooling for the MCR, the generator is located on the east end of the Turbine Building Mezzanine level, which is down one level from the MCR.

The fan is placed outside the east MCR entrance door, and the duct sections from the fan are positioned to direct cooling air flow into the control room. The extension cords provide power from the generator on the Turbine Building Mezzanine level to the fan. The Turbine Building is an open structure and this location is open to the atmosphere. Exhaust from the generator and any vapors during refueling of the generator will not accumulate in the area. Also due to the physical distance the generator is located from the MCR and the fan suction, exhaust gases will not be introduced into the MCR.

(Note: These actions are now contained in EOP-ECA-0.0, Loss Of All AC Power, which superseded EPP-1)

When the generator is removed from the storage location and placed on the east end of the Turbine Mezzanine level, transient combustible controls are placed into effect in accordance with AD-EG-ALL-1520, Transient Combustible Control. This procedure addresses minimizing the introduction of transient fire loads and reducing the fire hazards involved with the handling, use, and storage of combustible material to a degree consistent with personnel and plant safety.

SSA RAI 11 LAR Attachment S, Table S-2, Modification Items 10, 11, 12, 13, and 14 identified additional indication and cut-out switches necessary to eliminate self-induced station blackout (SISBO) strategy to allow for necessary operator actions.

a)

Provide a more detailed description of these modifications.

b)

As stated in the risk-informed characterization for each modification, no PRA or recovery credit is given and the modification is to ensure the procedure revisions for SISBO elimination are feasible. Clarify if these modifications are necessary for the NSCA.

c)

Clarify whether the new switching and monitoring actions are included in the LAR Attachment G, and are considered recovery actions, actions in the Control Room, or actions at a primary control station(s).

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d)

In LAR Attachment C, the overview for Fire Area B indicates no modification is credited for the area. Provide a clarification for the contradiction with LAR Attachment S, Table S-2, for the above modification items.

Response

a.

Modifications 10, 11, 12, and 13 are to provide additional indication on a panel in the charging pump room. These new indications will provide the operator cues for the status of system /

equipment at the Charging Pump Panel in support of the NSCA safe shutdown strategy. This is needed should a fire in the main control room propagate to hot gas layer and the potential for the loss of both emergency buses and or supporting equipment exists.

Modification 14 installs isolation switches in the control room for isolation of Auxiliary Panel DC

& GC from the control room. This obviates the need for the time critical manual operator action in the Battery Room applied in the current analysis.

Provide position indication for V6-12A, V6-12B, and V6-12C and operability indication for SW Pumps A, B, C.

Provide B and C Component Cooling Water Pumps with indication at the Charging Pump Room shut down panel 12 Provide SW Pressure Indication 13 Provide voltage indication for E-1, E-2 and DS Bus voltages.

14 Install cut out switch for Auxiliary panels GC and DC in the control room

b.

While not credited for PRA, the subject modifications are in support of the NSCA to facilitate the change in the safe shutdown strategy from the current SISBO approach to a Non-SISBO approach. The installation of the Isolation / cut out switches in the control room will require a control room action to implement. All other modifications will be installed at the Charging Pump Room Panel which is considered a Primary Control Station.

Specifically, the installation of the Auxiliary Panel DC & GC Isolation Switches in the control room obviates the need for the time critical manual operator action in the Battery Room applied in the current analysis. The current manual operator action requires Operations to open the 125VDC Circuit breakers that supply Auxiliary Panels DC & GC electrical power at 125VDC Distribution Panels A & B. The action is intended to fail close the RCS and Secondary side valves assuming spurious operations of the subject valves. The installation of the Auxiliary Panel DC &

GC Isolation Switches in the control room is intended to allow a control room operator action to perform the function rather than a breaker action in the plant..

The basis for the other proposed modifications was to provide the operator cues for the status of system / equipment at the Charging Pump Panel in support of the NSCA safe shutdown Page 12 of 44

strategy. This is needed should a fire propagate to hot gas layer and the potential for the loss of both emergency buses and or supporting equipment exists.

In general, for the high risk scenarios, it is intended to maintain operators in the control room, at the Charging Pump Room Panel and the Secondary Control Panel as part of the response strategy. The additional modifications will provide the operator at the Charging Pump Room Panel the status of the emergency and dedicated shutdown bus voltages as well as other key system / component statuses as part of the fire response strategy.

This will facilitate the implementation of any additional operator actions in a timely manner. For example, should both emergency buses be damaged by the fire, the transfer to dedicated shutdown becomes more efficient as the operator is on station and has the necessary operator cues to understand the status of the plant. The charging pump room panel is a Primary Control Station if the control room has to be abandoned. For all areas except Fire Area A18, these actions are characterized Defense-In-Depth Recovery Actions.

The additional modifications referenced in LAR Attachment S, Table S-2 (items 10 - 14) are being installed in the Charging Pump Room (Fire Area B, items 10-13) and in the Main Control Room (Fire Area A18, item 14) as part of the elimination of the Self Induced Station Blackout (SISBO) strategy employed under the Appendix R licensing basis.

c.

The actions for the SISBO modifications will be included in the revised Attachment G submitted with the 120 day responses.

d)

LAR Attachment S, Table S-2 was not meant to imply that the modifications were credited for Fire Area B. Rather, that is where the modifications discussed in Items 10-13 will be installed.

The modifications are being installed as part of the plant's overall efforts to reduce reliance on the SISBO strategy previously credited in several fire areas.

Revisions to Attachment G (part d) and LAR Table S-2 (part b) will be updated with the 120 day responses.

Fire Modeling (FM) Request for Additional Information (RAI) 01.a NFPA 805, Section 2.4.3.3, states that "the PSA [probabilistic safety assessment] approach, methods, and data shall be acceptable to the AHJ [authority having jurisdiction]..."

The NRC staff noted that fire modeling comprised the following:

Fire Dynamics Tools (FDTs) were used for zone of influence (ZOI) calculations of cabinets, pumps, motors, oil fires and transient fire sources, and to evaluate the development and timing of Hot Gas Layer (HGL) conditions in selected compartments.

The Consolidated Fire Growth and Smoke Transport (CFAST) model was used to calculate MCR abandonment times and to determine HGL temperature, optical density and Halon system activation time for a specific analysis in Fire Zone 20.

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The FLASH-CAT model was used to calculate the fire propagation in a vertical stack of horizontal cable trays in Fire Zone 20.

The Generic Fire Modeling Treatments (GFMTs) were used to determine 'initial' severity factors.

LAR Section 4.5.1.2, "Fire PRA," states that fire modeling was performed as part of the FPRA development (NFPA 805 Section 4.2.4.2). Reference is made to LAR Attachment J, "Fire Modeling V&V

[verification and validation]," for a discussion of the acceptability of the fire models that were used.

Regarding the acceptability of the PRA approach, methods, and data:

a.

Identify any fire modeling tools and methods that have been used in the development of the LAR and that are not discussed in LAR Attachment J.

Response

a.

The LAR, Attachment J, Table J-1, has been updated to include the point source radiation model, which was used in P2217-2300-01-03, Rev 3, "Robinson Fire PRA Exposed Structural Steel-Fire Interaction Analysis".

Technical details regarding the fire modeling analysis are have been provided in FM RAI 03.a and FM RAI 03.c. The update to Attachment J, Table J-1 will be provided with the 120-day responses.

All other fire modeling tools and methods that have been used in the development of the LAR are discussed in LAR Attachment J.

FM RAI O1.f NFPA 805, Section 2.4.3.3, states that "the PSA [probabilistic safety assessment] approach, methods, and data shall be acceptable to the AHJ [authority having jurisdiction]

The NRC staff noted that fire modeling comprised the following:

Fire Dynamics Tools (FDTs) were used for zone of influence (ZOI) calculations of cabinets, pumps, motors, oil fires and transient fire sources, and to evaluate the development and timing of Hot Gas Layer (HGL) conditions in selected compartments.

The Consolidated Fire Growth and Smoke Transport (CFAST) model was used to calculate MCR abandonment times and to determine HGL temperature, optical density and Halon system activation time for a specific analysis in Fire Zone 20.

The FLASH-CAT model was used to calculate the fire propagation in a vertical stack of horizontal cable trays in Fire Zone 20.

The Generic Fire Modeling Treatments (GFMTs) were used to determine 'initial' severity factors.

LAR Section 4.5.1.2, "Fire PRA," states that fire modeling was performed as part of the FPRA development (NFPA 805 Section 4.2.4.2). Reference is made to LAR Attachment J, "Fire Modeling V&V

[verification and validation]," for a discussion of the acceptability of the fire models that were used.

Page 14 of 44

Specifically, regarding the acceptability of CFAST for the MCR abandonment times study:

f.

Provide the basis for the assumption in the MCR abandonment time calculations that the fire brigade is expected to arrive within 15 minutes. Describe the uncertainty associated with this assumption; discuss possible adverse effects of not meeting this assumption on the results of the fire PRA and explain how possible adverse effects will be mitigated.

Response

f.

From RNP-F/PSA-0067, Rev. 1, the RNP Fire PRA-Plant Partitioning and Ignition Frequency calculation, section 3.4.3 describes the fire brigade response time assumption as follows:

Recognizing that manual suppression in some scenarios included suppression activities by nonfire brigade personnel, Section 14 of NUREG/CR-6850, Supplement 1 (FAQ 08-0050) provides guidance for determining the manual nonsuppression probability, without requiring the separate consideration of the fire brigade response time. Part of this approach addresses cases where the fire brigade response time for the analyzed scenario is judged to be comparable to the industry average. FAQ 08-0050 also provided guidance for making adjustments where the fire brigade response time distribution is judged to be significantly different from that underlying the events reported in the EPRI Fire Events Database. In particular, scenario-specific adjustments are appropriate where the fire brigade response time is more than five minutes different from the nominal fire brigade response time.

Consistent with the guidance in Section 9.7 (FPIP-0150, Rev. 1), fire brigade performance during an actual fire is estimated from the measured fire brigade response times during drills, with the use of a correction factor (i.e., 50% or a minimum of 10 minutes) to account for the artificialities associated with drills. The fire brigade response times, as measured during drills conducted over a period of several years, were documented in Attachment 24 (RNP Fire Brigade Response Times 2004-2009). Consistent with the guidance in Section 9.7 (FPIP-0150, Rev. 1), all times less than 10 minutes are assumed to represent fires that were suppressed by the personnel on the scene before the fire brigade arrived and are thus not indicative of the fire brigade performance.

Based on these drill times, the nominal fire brigade response time is estimated to be between 10 and 11 minutes, without any scenarios identified as outliers taking more than approximately five additional minutes. Because this compares very favorably with the 10 minutes for full fire brigade response which was assumed by FAQ 08-0050 to generate the nonsuppression curves, use of the approach described in FAQ 08-0050 is judged to be appropriate.

FM RAI 01.g NFPA 805, Section 2.4.3.3, states that "the PSA [probabilistic safety assessment] approach, methods, and data shall be acceptable to the AHJ [authority having jurisdiction]

The NRC staff noted that fire modeling comprised the following:

Page 15 of 44

Fire Dynamics Tools (FDTs) were used for zone of influence (ZOI) calculations of cabinets, pumps, motors, oil fires and transient fire sources, and to evaluate the development and timing of Hot Gas Layer (HGL) conditions in selected compartments.

The Consolidated Fire Growth and Smoke Transport (CFAST) model was used to calculate MCR abandonment times and to determine HGL temperature, optical density and Halon system activation time for a specific analysis in Fire Zone 20.

The FLASH-CAT model was used to calculate the fire propagation in a vertical stack of horizontal cable trays in Fire Zone 20.

The Generic Fire Modeling Treatments (GFMTs) were used to determine 'initial' severity factors.

LAR Section 4.5.1.2, "Fire PRA," states that fire modeling was performed as part of the FPRA development (NFPA 805 Section 4.2.4.2). Reference is made to LAR Attachment J, "Fire Modeling V&V

[verification and validation]," for a discussion of the acceptability of the fire models that were used.

Specifically, regarding the acceptability of CFAST for the MCR abandonment times study:

g.

The kitchen adjacent to the MCR has been excluded from the computational domain as the door between the kitchen and the MCR is fire rated. Provide technical justification for not considering scenarios, where the kitchen door is blocked open and the fire originates in the kitchen.

Response

g.

Fire scenarios in the Kitchen with the door propped open are bound by the workstation fire scenarios (severe transient) located within the MCR proper. This is true because the workstation fire is placed directly into the MCR and has a comparable fuel load and expected fire size as a fire in the Kitchen. However, the Kitchen is a sub-enclosure within the MCR and combustion products generated by a fire within the Kitchen must flow out a door opening into the MCR. This introduces a flow restriction as well as additional entrainment as compared to the workstation fire located within the MCR. Accordingly, the workstation fire is bounding and may be used to characterize the effects of a Kitchen fire.

FM RAI 01.h NFPA 805, Section 2.4.3.3, states that "the PSA [probabilistic safety assessment] approach, methods, and data shall be acceptable to the AHJ [authority having jurisdiction]..."

The NRC staff noted that fire modeling comprised the following:

Fire Dynamics Tools (FDTs) were used for zone of influence (ZOI) calculations of cabinets, pumps, motors, oil fires and transient fire sources, and to evaluate the development and timing of Hot Gas Layer (HGL) conditions in selected compartments.

Page 16 of 44

The Consolidated Fire Growth and Smoke Transport (CFAST) model was used to calculate MCR abandonment times and to determine HGL temperature, optical density and Halon system activation time for a specific analysis in Fire Zone 20.

The FLASH-CAT model was used to calculate the fire propagation in a vertical stack of horizontal cable trays in Fire Zone 20.

The Generic Fire Modeling Treatments (GFMTs) were used to determine 'initial' severity factors.

LAR Section 4.5.1.2, "Fire PRA," states that fire modeling was performed as part of the FPRA development (NFPA 805 Section 4.2.4.2). Reference is made to LAR Attachment J, "Fire Modeling V&V

[verification and validation]," for a discussion of the acceptability of the fire models that were used.

Specifically, regarding the acceptability of CFAST for the MCR abandonment times study:

h. The HRR profile of IEEE-383 unqualified thermoplastic cables was used for electrical cabinet fires in the MCR as the small quantities of IEEE-383 qualified thermoset cable do not affect the overall HRR. Show that the assumption of using thermoplastic cable HRR is consistent with the actual cable types used in the MCR electrical cabinets or provide a technical justification for this assumption in the context of the fire modeling analysis.

Response

h.

As stated in FM RAI 02a, submitted with the 60 day RAI responses, in cases where there is a mixture of thermoset and thermoplastic cables, thermoplastic damage criteria is used. Fire scenarios involving electrical panels containing cables are treated as thermoplastic electrical panels. This generally results in a more adverse risk contribution due to the differences in the severity factor distribution. This may be quantitatively shown by evaluating probability of control room abandonment for the four panel fire scenarios considered in the MCR abandonment report generated using the heat release rate profile, severity factor, and fuel properties for thermoset cables. The results of this computation are summarized in Table RAI H-1. The total probability of control room abandonment in this case is defined as the sum of the product of the non-suppression probability and severity factor for each of the fifteen heat release rate bins. The original thermoplastic risk contribution is based on the heat release rate profiles and severity factors for the NUREG/CR-6850 Appendix E Case 3 (single bundle) and Case 4 (multiple cable bundle) electrical panel ignition sources. The thermoset risk contribution is based on the heat release rate profiles and severity factors for the NUREG/CR-6850 Appendix E Case 1 (single bundle) and Case 2 (multiple cable bundle) electrical panel ignition sources. In this example, Ventilation Configuration 1 from the MCR abandonment report is used, which is normal HVAC with all boundary doors closed. The fuel properties for the thermoset cables are determined using the highest soot yield thermoset cable as listed in Table 3-4.16 of the 4 th Edition of the SFPE Handbook of Fire Protection Engineering.

Page 17 of 44

Table RAI H Comparison of the Risk Contribution for Thermoset and Thermoplastic Electrical Panel Fire Scenarios in the RNP MCR.

Total Probability of Control Room Abandonment for:

Multiple Cable Electical anelMultiple Cable Electrical Panel Single Cable Multiple Cable Bundle Electrical Bundle Electrical Bundle Electrical Bundle Electrical Panel Fire Cable Type Panel Fire Panel Fire Panel Fire Scenario in the Scenario in the Scenario Scenario MCBs MCBs (Propagating)

Thermoplastic 0.00219 0.0151 0.0202 0.0226 (Original)

Thermoset 0.00920 0.0369 0.0174 0.0187 (Sensitivity Case)

Table RAI H-1 shows that a non-MCB fully thermoset panel would have a more adverse effect on the risk. The reverse is true for an MCB panel ignition source fire scenarios. The reason the non-MCB panels result in an increased risk is due to the higher soot yields of the thermoset material coupled with the higher heat release rates for individual heat release rate bins. In these cases, the offsetting severity factor distribution does not fully compensate.

A simple but bounding estimate of the maximum thermoset cable fraction that may be present without causing significant change in the risk contribution may be made by adjusting the fuel composition while leaving the heat release rate profile unchanged. This is conservative because the heat release rate would either remain constant or decrease in combination with the improved fuel properties as the thermoset fraction is reduced. An iterative solution shows that an eight percent thermoset cable fraction produces a fifteen percent or lower change in the risk for the single and multiple cable bundle non-MCB electrical panel ignition source fire scenarios.

Since this is smaller than the uncertainty in the heat release rate input parameter per Section 3-2 of the SFPE Handbook of Fire Protection Engineering, the variation is not considered significant. The maximum fraction of thermoset cables in the main control room is less than eight percent given that the cables are predominantly thermoplastic. Accordingly, the results as based on thermoplastic electrical panels are representative of the abandonment conditions or are within the uncertainty of the heat release rate, which is the primary input parameter.

FM RAI O1.i NFPA 805, Section 2.4.3.3, states that "the PSA [probabilistic safety assessment] approach, methods, and data shall be acceptable to the AHJ [authority having jurisdiction]...

The NRC staff noted that fire modeling comprised the following:

Page 18 of 44

Fire Dynamics Tools (FDTs) were used for zone of influence (ZOI) calculations of cabinets, pumps, motors, oil fires and transient fire sources, and to evaluate the development and timing of Hot Gas Layer (HGL) conditions in selected compartments.

The Consolidated Fire Growth and Smoke Transport (CFAST) model was used to calculate MCR abandonment times and to determine HGL temperature, optical density and Halon system activation time for a specific analysis in Fire Zone 20.

The FLASH-CAT model was used to calculate the fire propagation in a vertical stack of horizontal cable trays in Fire Zone 20.

The Generic Fire Modeling Treatments (GFMTs) were used to determine 'initial' severity factors.

LAR Section 4.5.1.2, "Fire PRA," states that fire modeling was performed as part of the FPRA development (NFPA 805 Section 4.2.4.2). Reference is made to LAR Attachment J, "Fire Modeling V&V

[verification and validation]," for a discussion of the acceptability of the fire models that were used.

Specifically, regarding the acceptability of CFAST for the MCR abandonment times study:

i.

Provide details about the flow opening used between the MCR volume and the interstitial space above the MCR acoustic ceiling. Demonstrate that this opening is consistent with the actual plant configuration, and if not, provide technical justification for this opening size.

Response

i.

The flow connection between the MCR and the interstitial space connects, as shown in Figure 5-5, and described in Table 5-5, is 0.0253 m2 (0.273 ft2) for boundary leakage and 8.64 m 2 (93 ft 2) for the opening in the false ceiling above the MCB electrical panels. The basis for this is the actual configuration of the MCR. Specifically, the boundary leakage is determined from leakage fractions and does not specifically credit any individual flow paths in the ceiling. The larger opening above the MCBs is determined from the plan dimensions of the MCB panels.

Note that when fires are postulated in the MCBs, the large flow opening dominates and a single volume representation of the interstitial space and the MCR area is used (i.e., no direct model of the flow opening). Conversely, for fires are postulated elsewhere, only the smaller boundary leakage opening is used. There are localized areas where tiles were missing at time the walkdowns, which provide a larger flow opening than assumed in the analysis for boundary leakage; however, these larger openings were not credited because they are expected to be variably present. The sensitivity analysis provided in Section A.2.2.1 of the MCR abandonment report provides confirmation that a configuration with the false ceiling in place provides a more conservative result for fires outside the MCBs.

Page 19 of 44

FM RAI 01.j NFPA 805, Section 2.4.3.3, states that "the PSA [probabilistic safety assessment] approach, methods, and data shall be acceptable to the AHJ [authority having jurisdiction]...