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POLICY ISSUE
(Information)

SECY-06-0068

March 24, 2006

• PURPOSE
• BACKGROUND
• DISCUSSION
• COORDINATION

PURPOSE:

To inform the Commission that the staff intends to issue the subject generic letter (GL). This paper does not address any new commitments or resource implications.

BACKGROUND:

In 1981, the NRC issued Section 50.48 of Title 10 of the Code of Federal Regulations (10 CFR), the fire protection rule. The rule requires protection of safe shutdown capabilities in the event of a fire. One means of complying with this requirement is to separate one safe shutdown train from its redundant trains using rated fire barriers. Consequently, a number of licensees installed Hemyc and MT fire barrier systems in U.S. nuclear power plants (NPPs) to protect circuits and other electrical and instrumentation components and/or systems in accordance with regulatory requirements and plant-specific commitments.

In 1989, fire barrier performance became an issue with the failure of Thermo-Lag fire barriers to pass performance tests. The NRC issued several generic communications relating to nonconforming fire barrier configurations, and, based on these communications, licensees committed to take corrective actions. The staff also developed an action plan to resolve the Thermo-Lag issue. The action plan included implementation of a fire protection functional inspection program.

In 1999, plant-specific fire protection inspection findings raised concerns about the performance of Hemyc and MT fire barriers. The NRC regional offices and the Office of Nuclear Reactor Regulation (NRR) established a task interface agreement to address the concerns. The NRC concluded that existing testing was likely insufficient to properly qualify either Hemyc or MT as rated fire barriers.

In 2005, the NRC completed the confirmatory fire endurance test program for Hemyc and MT fire barriers, which began in 2001. These tests were based on National Fire Protection Association (NFPA) Standard 251, "Standard Methods of Fire Tests of Building Construction and Materials" (essentially equivalent to American Society for Testing and Materials (ASTM) Standard E-119, "Fire Test of Building Construction Materials"). The configurations tested modeled typical Hemyc and MT configurations used in nuclear power plants and were based on industry input. For thermocouple arrangement and spacing, the staff also applied guidance from GL 86-10, Supplement 1, "Fire Endurance Test Acceptance Criteria for Fire Barrier Systems Used To Separate Redundant Safe Shutdown Trains Within the Same Fire Area."

The NRC test results conducted in March and April 2005 indicated that the NRC tested Hemyc fire barriers did not meet the NFPA thermal acceptance criteria for a 1-hour fire rating for Hemyc, and the NRC tested MT fire barriers did not meet the criteria for a 3-hour rating. In April 2005, the NRC issued Information Notice 2005-07, "Results of Hemyc Electrical Raceway Fire Barrier System Full Scale Fire Testing," notifying licensees of the test findings. Hemyc and MT installed in configurations that are not capable of providing the designed level of protection are considered nonconforming installations. However, NRC recognized that plant-specific assessments are needed to determine compliance with existing regulatory requirements for any plant that relies on Hemyc and/or MT for compliance. Therefore, the staff concluded that the information notice should be followed up with a GL.

DISCUSSION:

In the GL, the staff of the U.S. Nuclear Regulatory Commission (NRC) asks licensees of light-water nuclear power reactors to inform the NRC whether they use Hemyc or MT fire barrier systems at their facilities. The staff requests that licensees who use Hemyc or MT inform the NRC whether they continue to conform with the plant’s licensing basis, in light of the recent test results, the compensatory measures adopted for nonconforming conditions, and the planned corrective actions. In addition, the staff requests that all licensees provide a description of the controls that were used to ensure that other fire barrier types relied on for separation of redundant trains of safe shutdown equipment located in a single fire area are capable of providing the necessary level of protection. A copy of the proposed GL is provided as Enclosure 1 . The staff dispositioned public comments (Enclosure 2 ) on the draft GL published in the Federal Register on July 25, 2005.

If licensees identify nonconforming conditions, they have several options. A licensee may make plant modifications, for example, replacing the Hemyc or MT fire barriers with an appropriately rated fire barrier material, upgrading the Hemyc or MT to a rated barrier, or rerouting cables or instrumentation lines through another fire area. Alternatively, licensees may voluntarily commit to 10 CFR 50.48(c), the NFPA 805 standard, follow the process in the rule and the NFPA 805 standard, and establish compliance through the application of technical evaluations that consider potential adverse effects, risk, defense-in-depth (DID), and safety margins.

Since the Hemyc and MT tests revealed that the fire barrier systems did not meet the acceptance criteria, the staff concluded that performance of other fire barrier systems may also be suspect. Therefore, the GL also requests a description of controls that were used to ensure the adequacy of other fire barrier types. This request is consistent with the earlier GL 92-08, which conveyed the staff’s expectation that fire barrier systems other than Thermo-Lag be assessed in light of the findings on Thermo-Lag. This is a change from the draft GL that the staff issued for public comment, but the staff’s position is that nonconforming conditions may exist with other fire barriers providing separation for redundant trains in a single fire area. This staff position is based on historical issues identified with various other fire barriers and the staff’s position that fire barrier issues may stem from a generic problem with licensees installing fire barriers improperly. Additionally, the staff simplified some of the discussion in the GL and clarified the requested information.

The staff has assessed whether immediate regulatory action is necessary while licensees respond to the subject GL, and has determined that continued operation is justified for several reasons. As a 1-hour rated fire barrier, Hemyc is installed only in fire areas where fire detection and automatic fire suppression systems are present or the licensee has previously obtained an approved exemption to the automatic fire suppression requirement because such suppression was deemed unnecessary (for example, there is negligible fire potential). The Hemyc fire barrier systems used at the plant are, therefore, just one of several layers of DID (fire detection, manual suppression, and automatic suppression are other layers of DID).

In addition, the ASTM-E119 standard fire test performed by the NRC exposed the Hemyc material to higher temperatures and more rapid rises in temperature than are expected to occur due to a fire in fire areas where Hemyc fire barrier systems are installed. The NRC considers the safety margins between the test and actual conditions to be wide enough that the integrity of installed Hemyc fire barrier systems is unlikely to be challenged.

For MT (which consists of several layers of materials, the outermost being Hemyc), the staff also concluded that the risk was low because, in NRC confirmatory testing, MT provided nearly an hour of protection in every test run, providing sufficient time for fire suppression by a fire brigade before cable damage is expected to occur.

During the December 8, 2005, public meeting of the Advisory Committee on Reactor Safeguards (ACRS) on the subject GL, a Nuclear Energy Institute (NEI) representative commented that the information request for a description of programmatic controls in place to ensure the adequacy of other fire barrier types is a backfit. The NEI representative also said this was "another example" of how the staff misuses GLs to backfit the industry.

The staff disagrees with NEI because the GL is a request for information. Furthermore, the GL addresses some of the same issues communicated in GL 92-08, that fire barrier systems other than Thermo-Lag be assessed for potential degradation in light of the findings on Thermo-Lag. GL 92-08 did not require any response from addressees regarding barriers other than Thermo-Lag. The industry failed to identify the inadequacy of Hemyc and MT. The staff has, therefore, concluded that a written response is necessary to assure the ability of fire barrier systems to perform their intended safety function.

On January 20, 2006, the Director of the Office of Nuclear Reactor Regulation (NRR) published a notice in the Federal Register (71 FR 3344) announcing the issuance of a Director's Decision granting in part a 10 CFR 2.206 petition filed by the Nuclear Information and Research Service (NIRS). The petition requested, among other things, that the NRC determine the extent of condition of the inoperable fire barriers through the use of a generic communication, and require sites that use these fire barriers to provide justification for operation in their response to the generic communication. The Director of NRR granted these requested actions in the petition and will use the generic communication process to perform the requested actions. Issuance of this GL constitutes the regulatory action referred to in the Director's Decision.

COORDINATION:

The Committee To Review Generic Requirements (CRGR) reviewed the GL on November 29, 2005, and endorsed it after the staff incorporated the CRGR comments. The ACRS reviewed the GL on December 8, 2005, and recommended that it be issued. The Office of the General Counsel reviewed the GL and had no legal objection to its content. The Office of the Chief Financial Officer reviewed the GL and had no objections based on budget or financial management concerns or potential resource impacts.

The subject GL is not a major "rule" under the Small Business Regulatory Enforcement Fairness Act of 1996, and the Office of Management and Budget has confirmed this determination.

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