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5.22.2025 NEI 24-11 Public Meeting, NEI Slides
	ML25148A423
Person / Time
Site:	Nuclear Energy Institute
Issue date:	05/22/2025
From:	Andy Campbell, Kleinsorg E; Nuclear Energy Institute
To:	; Office of Nuclear Reactor Regulation
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Response

Onsite Structural

Response

Purpose of the Report

©2025 Nuclear Energy Institute 4 Ability to safety shutdown the reactor Tied offsite only response to NRC acceptance of alternative onsite staffing levels Changes from last revision Onsite Structural Fire Brigade Recommended Is the fire expected to be contained within ignition source?

Can the fire be suppressed automatically?

Offsite Response Org response time acceptable?

Offsite Fire Response Organization Acceptable Input to Fire Response Evaluation (FHA, FSSA, and FPRA)

Has Offsite Response Org been provided with specialized training?

Can the reliability of Offsite Response Org and its mutual aid be verified?

Will Offsite Response MOU /

contract guarantee response/

service level?

For Fire Areas containing Equipment Important to Safety Identify the expected types of fires*

No No No No Onsite Incipient Fire Brigade Acceptable No Is the fire expected to be suppressed in the incipient stage?

No Yes Yes Yes Yes Yes Yes No Yes 6.2.3 Onsite Incipient Brigade 6.2.4 Offsite Fire

Response

Org. Adequacy 6.2.1 - SSD Ensured Alternative Onsite Staffing levels approved by NRC 6.2.2 - Need for Onsite Fire

Response

A A

The ability of fire area boundaries to contain the postulated fires, is an underlying assumption in these assessments

Provide summary of our initial thoughts

Any additional NRC thoughts/clarifications Spend time with comments where additional clarification is desired NRC Comments

Although it is described as risk-informed throughout, it is unclear how the process described in the document is risk-informed in the way that it is currently understood.

Understand and will address 2

When is it envisioned that the determination on fire brigade staffing would be made?

Construction Permit Application? Operating License Application?

See comment 13 3

Flow Chart:

There does not appear to be a way to get to a Structural Fire Brigade result except through some insufficiency in offsite response.

It is unclear whether you can get to Offsite Response Only result using the flowchart.

The Circle A transfer should go to the response time box, rather than the specialized training box.

What is the asterisk in the box labeled For Fire Areas containing Equipment Important to Safety Identify the expected types of fires* intended to indicate?

Section 6.2.4 includes: Will a memorandum of understanding (MOU)/contract need to be entered into to guarantee response and service level?

Whereas Figure 6-2, spot 13 includes: Will offsite response org accept MOU or contract for site response? Why the difference?

Understand and will address

Section 3.3 concludes with a statement on the suitability of using guidance for non-power reactors for micro reactors. It would be useful to have a definition of micro reactors, at least its intended use in this document.

Understand and will address 5

Section 6.2.2, Determine the Need for Onsite Fire Response, includes: In the event of very small reactors approved to operate for specific applications (e.g.,

micro-reactors), the safety features of the design could allow for sole reliance on offsite fire response. This statement and further discussion on micro-reactors in this section imply a size limitation on the determination of acceptability of offsite only fire response that is not borne out in the rest of the document.

6 It seems that if there is a special fire hazard at the plant (such as sodium or other combustible/toxic coolant or moderator) that it would be difficult to justify the incipient fire brigade or offsite response only results.

Understand and will address 7

This document would benefit from a more explicit definition of incipient fire brigade, in particular on the appropriate size.

Understand and will address

Section 6.2.2 includes the sentence: If the ability to achieve and maintain safe shutdown is ensured, given a fire in any fire area without operator intervention, and alternative onsite operations staffing has been approved by the NRC, then offsite fire response could be utilized and is presented in Figure 6-2. [emphasis added]

This indicates that this alternate staffing approval is a prerequisite for the offsite only determination, but it is unclear to the NRC when, and through what process, this approval would be granted, or in what document.

9 Section 6.2.4 includes: If the capability and reliability of the offsite fire response organization is not acceptable, then an onsite structural fire brigade is recommended Does this mean without an offsite response there must be a structural fire brigade? Is there an option of just an incipient fire brigade?

Understand and will address 10 Section 6.1 states the FSSA, Fire PRA, and FHA need to be in a stable state. What does this mean and who determines what stable state is?

Understand and will address 11 For the fire modeling in the FHA (i.e., for ZOI calculations) what will the source of the fire characteristics (like HRR) be? Standard PRA methods?

Understand and will address

©2025 Nuclear Energy Institute 9 Comments - continued Comment Path forward 12 Section 6.1 states that there can be offsite response only, where section 6.2.4 states that offsite response would be a supplement to the incipient fire brigade. Can there be offsite only or is it in addition to an incipient fire brigade?

Understand and will address 13 Suggest a section describing level of detail to be included in various types of submittals (CP, OL, COL, etc.).

14 The discussion of the information needed from the FHA seems to indicate that the fires under consideration involve fixed combustibles/ignition sources (i.e., electrical cabinets), and might be difficult to determine for other types, such as transients or pool fires.

Understand and will address 15 Would the individual with the necessary level of understanding of the plant described in Section 6.4 be present at all times?

Understand and will address 16 It is unclear how applicable the data on fire detection and suppression is to the proposed staffing levels because this data is from the current operating fleet which has staffing levels far above those in the current proposal.

Understand and will address

©2025 Nuclear Energy Institute 10 Comments - continued Comment Path forward 17 In the enumeration of the potential outcomes of the process, the Onsite Incipient Fire Brigade result should also indicate that offsite response is required.

Understand and will address 18 The document uses the term important to safety throughout. The advanced reactor community does not use this term. Consider changing.

Understand and will address 19 Footnote 2 [page 4] states: Note, the other sections of 10 CFR 50.48 [i.e., other than 50.48(a) -ed.] do not apply to the advanced reactor fleet. It is the position of the NRC that 50.48(f) would apply to advanced reactors undergoing decommissioning that are subject to 50.48.

Understand and will address 20 In Section 3.2.1 concerning guidance in Regulatory Guide 1.189, consider including discussion of RG sections 5.3.1 and 5.3.2.

21 In section 3.4.4, the guidance in Safety Standards Series documents NS-G-1.7, 2004 and NS-G-2.1, 2000 are mentioned, and it is noted that these two documents have been superseded by SSG-64 and SSG-77. Did the guidance change when these documents were superseded?

Understand and will address

Understand and will address 23 Section 5.2 includes the following:

Specific attention should also be given to high hazard fire sources (turbine fires, transformer fires, switchgear, etc.) and separating these hazards from equipment important to safety. These fires would not be expected to require a fire response greater than that provided by an incipient fire brigade, and therefore additional echelons of defense-in-depth should be provided. [emphasis added]

It is unclear why the underlined is correct.

Understand and will address 24 Section 5.3 includes the following:

The advanced reactor fleet should design passive fire barriers (including penetration seals, doors, and dampers) in accordance with guidance provided in RG 1.189 and should be or commensurate with the hazard in the fire area. [emphasis added]

Is the highlighted or extraneous?

Understand and will address

Based on the information contained in the FHA and the Fire PRA (if performed), and the plant design (factored in ZOIs), an assessment can be made of the fires that are expected to propagate beyond the ignition source (e.g., fires propagating outside of an electrical cabinet such that it could potentially damage adjacent cabinets/cable trays). [emphasis added]

Should factored be factoring?

Understand and will address 26 Section 6.2.4 Offsite Fire Response Organization Adequacy would be a good place to point to the guidelines from the NEIL Loss Control Manual identified earlier.

Understand and will address 27 Suggest adding SSG-64 and SSG-77 to the references, since they are the documents currently in effect.

Understand and will address 28 The color of the font in Figures 6-1 and 6-2 are difficult to read.

Understand and will address

Mid-July Publish NEI 24-11 Rev. 1 and submit to NRC for endorsement End of August Interim approval or confidence measure before Reg. Guide revision?

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