ML082140123
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| ML082140123 | |
| Person / Time | |
|---|---|
| Issue date: | 07/31/2008 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| O'Donnell, Edward, RES/DE/RGB, x6265 | |
| Shared Package | |
| ML082140105 | List: |
| References | |
| DG-1205, RG-1.047 | |
| Download: ML082140123 (2) | |
Text
U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REGULATORY RESEARCH
SUMMARY
OF PROPOSED CHANGES TO RG 1.47 The following is the summary of proposed changes to Revision 0 of Regulatory Guide (RG) 1.47, Bypassed and Inoperable Status Indication for Nuclear Power Plant Safety Systems.
- The current version of RG 1.47 endorses Institute of Electrical and Electronics Engineers (IEEE) Std 279-1971, Criteria for Protection Systems for Nuclear Power Generating Stations, which has since been withdrawn by the IEEE, although plants with construction permits issued between 1971 and 1999 still use it as part of their licensing design basis. The proposed Revision 1 of RG 1.47 endorses IEEE Std 603-1991. This version of RG 1.47 points out the differences between IEEE Std 279-1971 and IEEE Std 603-1991, which is the version specifically referred to in 10 CFR 50.55 a (h) (Codes and Standards applicable to Protection and Safety Systems). Both IEEE Std 603-1991 and IEEE Std 279-1971 list requirements with regard to bypassed and inoperable status indication for safety systems. The language used in IEEE Std 603-1991 is more specific than IEEE Std 279-1971 regarding bypassed and inoperable status indication.
- The provisions for automatic indication of bypassed and operable status of safety systems is listed as the requirements per 10 CFR 50.34(f)(2)(v), Additional TMI-Related Requirements.
- Regulatory Guide 1.118, Periodic Testing of Electric Power and Protection Systems, which endorses IEEE Std 338-1987, Criteria for the Periodic Testing of Nuclear Power Generating Station Safety Systems, is listed as an acceptable method for the periodic testing of electric power and protection systems.
- The proposed revision 1 of RG 1.47 incorporates Branch Technical Position (BTP) 7-17, Guidance on Self-Test and Surveillance Test Provisions, of NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants as guidance for self-test associated with digital computer-based Instrumentation and Controls (I&C) systems.
- BTP 8-5, Supplemental Guidance for Bypass and Inoperable Status Indication for Engineered Safety Features Systems is also incorporated as guidance associated with bypassed and inoperable status.
- A number of Regulatory Guides and IEEE Standards are referenced as guidance to meet regulations concerning equipment qualification, maintaining independence, single-failure criterion, common-cause/mode failures, diversity and defense-in-depth, and high functional reliability requirements.
- Regulatory Position 1 replaces system level term with safety system or subsystem. This position also incorporates a criterion of BTP 7-17 associated with bypassed and inoperable status of protection or safety system for testing, Provisions should also be made to allow operations staff to confirm that a bypassed safety function has been properly returned to service.
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- Regulatory Position 2 replaces protection system term with safety function.
- Regulatory Positions 3 and 4 of RG 1.47, Rev 0 are now explicitly present in IEEE Std 603-1991. Therefore, these positions should be removed.
- New Regulatory Position 3 with respect to digital I&C is added into the proposed revision of the regulatory guide. Detection by self-test or self-diagnostic capabilities of any inoperable condition of some portion of a digital safety system and/or any subsequent automatic compensatory action that results in any bypass or inoperable condition of some portion of a digital safety system should be indicated by means consistent with the other positions of the regulatory guide.
- New Regulatory Position 4 incorporates Position 6 of BTP 8-5: The bypass and inoperable status indication system should include a capability for assuring its operable status during normal plant operation to the extent that the indicating and annunciating function can be verified.
- New Regulatory Position 5 incorporates Positions 1 and 2 of BTP 8-5: Bypass and inoperable status indicators should be arranged such that the operator can determine whether continued reactor operation is permissible. The bypass of shared system protective functions should be indicated in the control room of all affected units.
- New Regulatory Position 6 incorporates Positions 4 and 5 of BTP 8-5: Bypass and inoperable status indicators should be designed and installed in a manner that precludes the possibility of adverse effects on plant safety systems. The indicator system should not be used to perform functions that are essential to safety, unless it is designed in conformance with criteria established for safety systems.
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