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POLICY ISSUE
(Notation Vote)

SECY-08-0093

June 30, 2008

• PURPOSE
• BACKGROUND
• DISCUSSION
• COMMITMENT
• RECOMMENDATION
• RESOURCES
• COORDINATION

PURPOSE:

This informs the Commission of the U.S. Nuclear Regulatory Commission (NRC) staff approach to resolving issues concerning fire-induced circuit failures and multiple spurious actuations.  This paper includes a description of staff efforts to resolve the technical details for analyzing and evaluating challenges to post-fire safe-shutdown capability.  This paper also requests that the Commission approve changes to the enforcement discretion guidance regarding fire-induced circuit failure violations.

BACKGROUND:

In Staff Requirements Memorandum (SRM) SECY-06-0196, "Issuance of Generic Letter 2006-XX, 'Post-Fire Safe-Shutdown Circuits Analysis Spurious Actuations,'" dated December 15, 2006, the Commission directed the staff to develop a clearly defined method of compliance to resolve fire-induced circuit failures for licensees who choose not to utilize the risk-informed approach contained in Title 10 of the Code of Federal Regulations Part50, Section 48(c) (10 CFR 50.48(c)) – National Fire Protection Association Standard (NFPA) 805.  The Commission also directed staff to encourage licensees to transition to 10 CFR 50.48(c) – NFPA 805. This paper also discusses the staff's plan to inform the Commission of other key fire protection activities.

DISCUSSION:

Staff Activities to Close Fire-Induced Circuit Failure Issues

The staff activities to provide closure to the issue of fire-induced circuit failures are described in detail in two enclosures to this paper.  Enclosure 1 provides a proposed clarification of NRC requirements regarding circuit protection and analysis or methods for licensees that are not adopting the risk-informed methods of 10 CFR 50.48(c) – NFPA 805.  Enclosure 2 includes the plan responding to the Commission's direction to develop guidelines that provide a clearly defined method of compliance for licensees for fire-induced circuit failures.

In order to provide clarification of NRC requirements, the staff proposes to define two classifications of equipment important to safe shutdown in the plant during a fire.  The first is described in 10 CFR Part 50, Appendix R, Section III.G.1.a (Section III.G.1.a) as one train of systems necessary to achieve and maintain hot shutdown conditions (see Enclosure 1 , Table 1, left column).  This equipment is a subset of the second and more general set of structures, systems and components important to safe shutdown described in Section III.G.1. As described below, the level of protection for each of these classifications of equipment is different.

For one train of systems necessary to achieve and maintain hot shutdown conditions (see Enclosure 1 , Table 1, left column) protection is required to meet Section III.G.2, "Fire Protection of Safe Shutdown Capability."  For this equipment, there is no allowance for manual actions, or methods other than various combinations of:  (1) physical separation (e.g., rated fire barriers or separation with no intervening combustibles); (2) fire detection; and/or (3) automatic fire suppression as described in Section III.G, to protect the train of systems necessary to achieve and maintain hot shutdown conditions.

Section III.G.1 also requires that fire protection features also be provided for the broader category of structures, systems and components, including circuits important to safe shutdown (right column of Enclosure 1 , Table 1).  However, for protection of this capability to safely shutdown, the same prescriptive requirements as listed in Section III.G.1.a and III.G.2 do not apply.  Regulatory Issue Summary (RIS) 2006-10, "Regulatory Expectations with Appendix R Paragraph III.G.2, Operator Manual Actions," provides a discussion protecting other safe shutdown equipment using methods such as manual actions, where one train of systems necessary to achieve and maintain hot shutdown conditions is protected in accordance with 10 CFR 50, Appendix R, III.G methods.

Since the issuance of SRM-SECY-06-0196, the staff had a number of meetings to provide industry with an opportunity for input into closure of this issue.  The industry, through the Nuclear Energy Institute (NEI), developed draft NEI 00-01, Revision 2, "Guidance for Post-Fire Safe‑Shutdown Circuit Analysis," to enhance an earlier method to evaluate multiple spurious actuations due to fire.  The staff sees value in certain attributes of the NEI document.  However, the document does not provide for complete closure of the circuit failure issue.  At a recent public meeting NEI acknowledged that further work is necessary on the draft document.

Based on discussions with industry representatives, the approach provided in Enclosure 1 clarifies circuit analysis requirements and will provide a technically sound and traceable regulatory framework that can be effectively implemented by the licensees.

Final disposition of the noncompliances will require analyses, plant changes, or submittals to the NRC for approval.  Protection of the train of systems necessary to achieve and maintain hot shutdown conditions (left column in Table 1 of Enclosure 1 ) is required to be in accordance with the prescriptive requirements of 10 CFR Part 50, Appendix R, Section III.G.  The existing guidance regarding protection (e.g. fire barriers and suppression systems) is sufficient for these purposes.

There are robust methods available for analyzing the protection of components important to safe shutdown but not required to achieve and maintain hot shutdown (the right column in Table 1 of Enclosure 1 ).  Currently, feasible and reliable operator manual actions and modifications in accordance with Section III.G are acceptable approaches to protecting safe shutdown capability.  The staff intends to work with industry, using the normal public regulatory process to enable stakeholder engagement, to develop guidelines that implement additional methods.

Circuits Enforcement Discretion

Currently, Enforcement Guidance Memorandum 98-002, Revision 2, "Disposition of Violations of Appendix R, Sections III.G and III.L Regarding Circuit Failures," provides enforcement discretion for fire-induced circuit failures where the licensee implements compensatory measures.  If the Commission approves the staff's recommendation, the staff estimates that it will take approximately 3 to 6 months to issue a regulatory issue summary, or other appropriate generic communication sharing the clarification discussed in Enclosure 1 of this paper with licensees.  Upon the issuance of the clarification to the licensees, the staff plans to issue a new enforcement guidance memorandum which will provide 6 months of enforcement discretion from the date of the clarification for licensees to identify, place noncompliances into their corrective action program, and institute compensatory measures.  At the end of the 6 months period available for licensees to identify noncompliances, the enforcement discretion period would continue for 30 months.  This period would allow time for licensees to resolve those noncompliances while maintaining compensatory measures in place.  Any additional noncompliances identified during this 30 month period would not receive enforcement discretion.  The overall enforcement discretion would expire approximately 3 years from the issuance of the clarification.  This would align the time frame for resolution to be about the same as the time for plants who select the option of utilizing the risk-informed approach in NFPA 805 as permitted by 10 CFR 50.48(c).

New Reactors

Although this paper discusses the staff approach to resolve compliance issues concerning fire-induced circuit failures and multiple spurious actions for existing reactors, the staff is also taking a consistent approach to this issue for new reactors.  However, because new reactor designs are integrating fire protection requirements, including the protection of safe-shutdown capability, into the planning and design phase for the plant, the potential for fire induced circuit failures and multiple spurious actuations to adversely affect the ability to shutdown is significantly reduced.  Examples of design features that significantly reduce the adverse affects of fire induced circuit failures include the use of fiber optic cabling and separation of redundant trains by passive barriers in all new reactor designs and the passive shutdown systems of some new reactors.  Enclosure 1 also provides a discussion of the regulatory framework for new reactor designs.

Other Fire Protection Activities

The staff, under the direction of the NRC's Fire Protection Steering Committee, plans to prepare an integrated plan to address and document closure of the current key fire protection activities.  The integrated plan will include a discussion of licensee transitions to NFPA 805, electrical raceway fire barriers, and post-fire operator manual actions.  The staff will notify the Commission regarding the resolution of these activities.

Backfit Discussion

This position and approach for resolving fire-induced circuit failures including multiple spurious actuations is consistent with current staff positions and practice regarding the interpretation of Appendix R as it relates to fire protection for safe shutdown capability.  This was most recently documented in RIS 2006-10. Specifically, paragraph III.G.2 Operator Manual Actions in Second Train of the RIS 2006-10 states:

. . . if one of the redundant trains in the same fire area is free of fire damage by one of the specified means in paragraph III.G.2 [left column of Table 1 of Enclosure 1 ], then the use of operator manual actions, or other means necessary, to mitigate fire-induced operation or maloperation to the second train [right column of Table 1 of Enclosure 1 ] may be considered in accordance with the licensee's fire protection program and license condition since paragraph III.G.2 has been satisfied.

RIS 2006-10 sets forth regulatory history documenting NRC interpretation and practice in the area of protection of safe shutdown capability.  The clarification in this paper is consistent with the position in RIS 2006-10.  Accordingly, the staff's positions stated in this paper do not constitute backfitting under 10 CFR 50.109 and no backfit analysis was performed.

COMMITMENT:

Upon approval of this paper the staff would issue new enforcement guidance in accordance with the discussion provided above.  Also, the staff would share the information in Enclosure 1 with the industry using established regulatory communication tools.  Lastly, the staff would develop or endorse guidance to include any additional methods that the staff accepts for circuit analysis.

RECOMMENDATION:

That the Commission approve issuing new enforcement discretion guidance related to fire-induced circuit failures.

RESOURCES:

To complete and implement the enforcement guidance change and to share the clarification with licensees, approximately 1 full-time equivalent position will be required. These resources are included in the current budget.

COORDINATION:

The Office of the General Counsel has reviewed this paper and has no legal objection.  The Office of the Chief Financial Officer has reviewed this paper and concurs.

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