Nuclear Safety:

NRC's Oversight of Fire Protection at U.S. Commercial Nuclear Reactor Units Could Be Strengthened

GAO-08-747: Published: Jun 30, 2008. Publicly Released: Jun 30, 2008.

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After a 1975 fire at the Browns Ferry nuclear plant in Alabama threatened the unit's ability to shut down safely, the Nuclear Regulatory Commission (NRC) issued prescriptive fire safety rules for commercial nuclear units. However, nuclear units with different designs and different ages have had difficulty meeting these rules and have sought exemptions to them. In 2004, NRC began to encourage the nation's 104 nuclear units to transition to a less prescriptive, risk-informed approach that will analyze the fire risks of individual nuclear units. GAO was asked to examine (1) the number and causes of fire incidents at nuclear units since 1995, (2) compliance with NRC fire safety regulations, and (3) the transition to the new approach. GAO visited 10 of the 65 nuclear sites nationwide, reviewed NRC reports and related documentation about fire events at nuclear units, and interviewed NRC and industry officials to examine compliance with existing fire protection rules and the transition to the new approach.

According to NRC, all 125 fires at 54 of the nation's 65 nuclear sites from January 1995 through December 2007 were classified as being of limited safety significance. According to NRC, many of these fires were in areas that do not affect shutdown operations or occurred during refueling outages, when nuclear units are already shut down. NRC's characterization of the location, significance, and circumstances of those fire events was consistent with records GAO reviewed and statements of utility and industry officials GAO contacted. NRC has not resolved several long-standing issues that affect the nuclear industry's compliance with existing NRC fire regulations, and NRC lacks a comprehensive database on the status of compliance. These long-standing issues include (1) nuclear units' reliance on manual actions by unit workers to ensure fire safety (for example, a unit worker manually turns a valve to operate a water pump) rather than "passive" measures, such as fire barriers and automatic fire detection and suppression; (2) workers' use of "interim compensatory measures" (primarily fire watches) to ensure fire safety for extended periods of time, rather than making repairs; (3) uncertainty regarding the effectiveness of fire wraps used to protect electrical cables necessary for the safe shutdown of a nuclear unit; and (4) mitigating the impacts of short circuits that can cause simultaneous, or near-simultaneous, malfunctions of safety-related equipment (called "multiple spurious actuations") and hence complicate the safe shutdown of nuclear units. Compounding these issues is that NRC has no centralized database on the use of exemptions from regulations, manual actions, or compensatory measures used for long periods of time that would facilitate the study of compliance trends or help NRC's field inspectors in examining unit compliance. Primarily to simplify units' complex licensing, NRC is encouraging nuclear units to transition to a risk-informed approach. As of April 2008, some 46 units had stated they would adopt the new approach. However, the transition effort faces significant human capital, cost, and methodological challenges. According to NRC, as well as academics and the nuclear industry, a lack of people with fire modeling, risk assessment, and plant-specific expertise could slow the transition process. They also expressed concern about the potentially high costs of the new approach relative to uncertain benefits. For example, according to nuclear unit officials, the costs to perform the necessary fire analyses and risk assessments could be millions of dollars per unit. Units, they said, may also need to make costly new modifications as a result of these analyses.

Recommendations for Executive Action

  1. Status: Closed - Not Implemented

    Comments: Initially, as with all the recommendations in this report, NRC initially did not make specific comments, but said the report was accurate and complete and stated it intended to give the findings and conclusions serious consideration. In its 60-day letter, NRC stated it has been working on resolving fire-wrap issues since the early 1990s; specifically, it has reviewed design and test results from vendors, observed fire barrier configurations at selected plants, performed small scale testing itself, and as a result has updated NRC guidance on testing and acceptance criteria. NRC adds it has taken additional steps including periodic safety inspections, issuance of generic communications, and the issuance of confirmatory orders. Importantly NRC states it issued Generic Letter 2006-03 addressing Hemyc and MT fire barrier issues, and based on licensees responses to the GL, NRC staff would complete inspection efforts to close out Hemyc and MT issues for plants that have not committed to adopting NFPA 805 (the risk-informed regulatory approach) by 12/31/08. On April 16, 2009, NRC advised us that it planned no additional tests on the fire wraps, because the fire wrap industry had performed additional qualifying tests in 2005 and 2006 with similar results to NRC testing. NRC informed plants in a memorandum dated 12/17/2008 that those that did not commit to NFPA-805 had resolved the fire barrier issues through approvals for amendments, or exemptions, or by completions of plant modifications to achieve compliance. NRC states it considers the recommendation closed and plans no further actions.

    Recommendation: To address long-standing issues that have affected NRC's regulation of fire safety at the nation's commercial nuclear power units, the NRC Commissioners should direct NRC staff to address long-standing concerns about the effectiveness of fire wraps at commercial nuclear units by analyzing the effectiveness of existing fire wraps and undertaking efforts to ensure that the fire endurance tests have been conducted to qualify fire wraps as NRC-approved 1- or 3-hour fire barriers.

    Agency Affected: Nuclear Regulatory Commission

  2. Status: Closed - Not Implemented

    Comments: In essence, NRC disagreed with the recommendation and likely will not implement it. As with all the recommendations in this report, NRC initially did not make specific comments, but said the report was accurate and complete and stated it intended to give the findings and recommendations serious consideration. In its 60-day letter, however, NRC stated that while the implementation of long-term interim compensatory measures is less than ideal, that situation does not introduce safety concerns because (1) defense in depth at nuclear plants provides adequate protection, and (2) NRC inspectors periodically inspect a sample of each plants compensatory measures for adequacy. NRC states that as part of its fire protection closure plan, NRC staff would resolve the issues that underlie the need for compensatory measures, and the Commission states that staff will develop "meaningful metrics" to gauge the progress of plan implementation. NRC stated in April 2009 that it considered the recommendation closed.

    Recommendation: To address long-standing issues that have affected NRC's regulation of fire safety at the nation's commercial nuclear power units, the NRC Commissioners should direct NRC staff to address safety concerns related to extended use of interim compensatory measures by (1) defining how long an interim compensatory measure can be used and identifying the interim compensatory measures in place at nuclear units that exceed that threshold, (2) assessing the safety significance of such extended compensatory measures and defining how long a safety-significant interim compensatory measure can be used before NRC requires the unit operator to make the necessary repairs or replacements or request an exemption or deviation from its fire safety requirements, and, (3) developing a plan and deadlines for units to resolve those compensatory measures.

    Agency Affected: Nuclear Regulatory Commission

  3. Status: Closed - Implemented

    Comments: NRC agreed with the recommendation and stated in its 60-day letter it would implement the recommendation by the end of FY2010. As with all the recommendations in this report, NRC initially did not make specific comments, but said the report was accurate and complete and stated it intended to give the findings and recommendations serious consideration. On 3/19/2010, NRC reported licensees track fire protection deficiencies, exemptions and deviations, including any involving compensatory measures and manual actions. NRC sampled those measures and manual actions during routine fire protection inspections. On that basis, NRC determined that existing compensatory measures and manual actions ensure adequate fire protection at each nuclear plant. Moreover, NRC reports that in December 2009, it completed the development of a centralized database of fire protection exemptions for operating nuclear reactors.

    Recommendation: To address long-standing issues that have affected NRC's regulation of fire safety at the nation's commercial nuclear power units, the NRC Commissioners should direct NRC staff to develop a central database for tracking the status of exemptions, compensatory measures, and manual actions in place nationwide and at individual commercial nuclear units.

    Agency Affected: Nuclear Regulatory Commission

  4. Status: Closed - Implemented

    Comments: CLOSED-IMPLEMENTED: NRC agreed with the recommendation, and as with all the recommendations in this report, NRC initially did not make specific comments, but said the report was accurate and complete and stated it intended to give the findings and conclusions serious consideration. In its 60-day letter, NRC stated it had been working since the mid-1990s to address the complex issue of fire-induced circuit failures. On June 20, 2008, NRC staff presented the Commission via SECY-08-0093 with an approach for resolving those issues, and the Commission approved the document by Sept. 3, 2008. A review of NRC literature shows that NRC implemented a "CAROLFIRE" initiative to address these issues. NRC stated that its staff plans to follow SECY-08-0093 and develop supporting guidelines by early FY09. In a March 19, 2010 letter to Chairman Carper, NRC stated that the Commission approved SECY-08-0093 in September 2008 and that appropriate changes were incorporated into SECY-08-171, "Plan for Stabilizing Fire Protection Regulatory Infrastructure" (SECY-08-171), which contained milestones and deliverables for implementing the Fire Protection Closure Plan, including a commitment to develop guidance to address longstanding concerns, including multiple spurious actuations. In October 2009, NRC issued the guidance as Rev. 2 to Reg. Guide 1.189.

    Recommendation: To address long-standing issues that have affected NRC's regulation of fire safety at the nation's commercial nuclear power units, the NRC Commissioners should direct NRC staff to address long-standing concerns by ensuring that nuclear units are able to safeguard against multiple spurious actuations by committing to a specific date for developing guidelines that units should meet to prevent multiple spurious actuations.

    Agency Affected: Nuclear Regulatory Commission

 

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