Information Notice 2016-01, Recent Issues Related to the Commercial Grade Dedication of Allen Bradley 700-RTC Relays
| ML15295A173 | |
| Person / Time | |
|---|---|
| Issue date: | 02/17/2016 |
| From: | Michael Cheok, Kokajko L Division of Construction Inspection and Operational Programs, Division of Policy and Rulemaking |
| To: | |
| References | |
| IN-16-001 | |
| Download: ML15295A173 (5) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
OFFICE OF NEW REACTORS
WASHINGTON, DC 20555-0001 February 17, 2016 NRC INFORMATION NOTICE 2016-01: RECENT ISSUES RELATED TO THE
COMMERCIAL GRADE DEDICATION OF ALLEN
BRADLEY 700-RTC RELAYS
ADDRESSEES
All holders of an operating license or construction permit for a nuclear power reactor under
Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of
Production and Utilization Facilities, except those that have permanently ceased operations
and have certified that fuel has been permanently removed from the reactor vessel.
All holders of and applicants for a power reactor early site permit, combined license, standard
design approval, or manufacturing license under 10 CFR Part 52, Licenses, Certifications, and
Approvals for Nuclear Power Plants. All applicants for a standard design certification, including
such applicants after initial issuance of a design certification rule.
All contractors and vendors that supply basic components to U.S. Nuclear Regulatory
Commission (NRC) licensees under 10 CFR Part 50 or 10 CFR Part 52.
PURPOSE
The NRC is issuing this information notice (IN) to inform addressees about recent issues related
to the commercial grade dedication (CGD) of Allen Bradley 700-RTC time delay relays, which
the manufacturer redesigned to use a complex programmable logic device (CPLD). The
dedicating entities, as defined in 10 CFR 21.3, Definitions, did not identify this design change, and as a result, failed to evaluate it as required by 10 CFR Part 50 Appendix B Criterion III,
Design Control. The NRC expects that recipients of this information notice will review the
information for applicability to their facilities, and consider actions, as appropriate, to avoid
similar problems. Suggestions contained in this IN are not NRC requirements; therefore, no
specific action or written response is required.
DESCRIPTION OF CIRCUMSTANCES
On May 20, 2015, Duke Energy, the licensee for the Brunswick Steam Electric Plant (BSEP)
submitted Licensee Event Report (LER) 325/2015-002, Emergency Diesel Generator Loss of
Safety Function, (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML15149A148) to the NRC. On November 16, 2015, the licensee submitted
Revision 1 to LER 325/2015-002 (ADAMS Accession No. ML15329A374), which among other
things, reflected a change in the corrective actions. Following an engineering evaluation, the
licensee determined that for a period of 12 minutes on March 21, 2015, during an emergency
ML15295A173 diesel generator (EDG) loading test, EDGs 3 and 4 could simultaneously have been unable to
tie to their respective emergency busses. This was due to Allen Bradley 700-RTC time delay
relays in the breaker control logic that were susceptible to electrical noise from electrically
connected or nearby relays de-energizing, which could have prevented the output breakers from
properly closing under certain conditions. The NRC considers this a loss-of-safety-function of
the onsite standby alternating current power source. The licensee implemented corrective
actions that included the installation of transient voltage suppressors across all four EDG relays.
Following this event, the licensee issued a 30-day notification to the NRC following the
requirements of 10 CFR 21.21, Notification of failure to comply or existence of a defect and its
evaluation, (ADAMS Accession No. ML15196A034). In this notification, the licensee identified
that the newer Allen Bradley 700-RTC time delay relays contain an unevaluated CPLD. The
incorporation of this CPLD was an unpublished design change that was implemented to replace
an integrated circuit chip, and did not result in a part number change.
NRC Problem Identification and Resolution Inspection Report 05000325/2015007 and 05000324/2015007 (ADAMS Accession No. ML15210A725), dated July 29, 2015, identified
that the licensee purchased and dedicated the relays using a material evaluation performed
in 1999. This material evaluation relied, in part, on dimensional and configuration checks to
ensure that no unforeseen design changes had occurred. The purchase specification for the
commercial grade component failed to identify a critical characteristic that needed to be verified
for this relay, (i.e., no inadvertent change in state). Allen Bradleys design change to replace an
integrated circuit with a different type of component introduced a new failure mechanism for the
relays safety function. The NRC requires that dedicating entities identify and evaluate such a
design change as part of their CGD processes. The aforementioned LER provides more
information on the specifics of the BSEP event, whereas the references mentioned in the
background section provide additional information associated with the development, selection, and testing of important critical characteristics when utilizing a CGD process.
In addition to BSEP, three additional dedicating entities (AZZ/ Nuclear Logistics, Inc., Nutherm
International, and United Controls International) informed the NRC through 10 CFR 21.21 notifications (ADAMS Accession Nos. ML15134A016, ML15161A230, and ML15205A293) that
they had supplied similar Allen Bradley 700-RTC time delay relays to licensees without
identifying a design change that introduced the potential for a new failure mechanism.
BACKGROUND
Regulations in 10 CFR Part 21, Reporting of Defects and Noncompliance, define CGD, in part, as an acceptance process undertaken to provide reasonable assurance that a commercial
grade item used as a basic component will perform its intended safety function, and in this
respect, is deemed equivalent to an item designed and manufactured under a quality assurance
program that meets the requirements of 10 CFR Part 50, Appendix B, Quality Assurance
Criteria for Nuclear Power Plants and Fuel Reprocessing Plants. This assurance is achieved
by identifying the critical characteristics of the item, and verifying their acceptability by
inspections, tests, or analyses performed by the purchaser or third-party dedicating entity. Regulations in 10 CFR Part 50 Appendix B, Criterion III, Design Control require, in part, subjecting design changes to control measures commensurate with those applied to the original
design.
Related NRC Generic Communications
Information Notice 2014-11, "Recent Issues Related to the Qualification and Commercial Grade
Dedication of Safety-Related Components" (ADAMS Accession No. ML14149A520), informs
addressees of issues identified during NRC vendor inspections with the qualification and CGD
of safety-related replacement components.
Information Notice 2011-01, Commercial-Grade Dedication Issues Identified During NRC
Inspections (ADAMS Accession No. ML103220180), summarizes the NRC staffs observations
and findings during vendor inspections in the area of CGD, as it applies to operating reactors.
Information Notice 1994-20, "Common-Cause Failures Due to Inadequate Design Control and
Dedication" (ADAMS Accession No. ML031060589), describes a common cause failure (CCF)
of an EDG load sequencer after the replacement of electromechanical time delay relays with
microprocessor-based time delay relays. The incident illustrates that a digital replacement can
produce a new susceptibility to CCF. In this case, the CGD did not adequately consider the
in-service environment to demonstrate the compatibility of the replacement component with the
operating environment.
Generic Letter 1991-05, Licensee Commercial-Grade Procurement and Dedication Programs
(ADAMS Accession No. ML031140508), expresses staff positions regarding certain aspects of
licensee commercial grade procurement, and dedication programs which would provide
acceptable methods to meet regulatory requirements.
Generic Letter, 1989-02, Actions to Improve the Detection of Counterfeit and Fraudulently
Marketed Products (ADAMS Accession No. ML031140060), describes the NRC staffs
perspective on good practices in procurement and dedication. The generic letter (GL) also
provided the NRC's conditional endorsement of the guidelines contained in Electric Power
Research Institute NP-5652, "Guideline for the Utilization of Commercial-Grade Items in Nuclear
Safety-Related Applications," issued in June 1988, for evaluating commercial grade products for
suitability for use in safety-related applications.
DISCUSSION
According to the requirements of 10 CFR Part 21, the CGD process is undertaken to provide
reasonable assurance that the relays will perform their intended safety functions, and in this
respect, are deemed equivalent to relays designed and manufactured under a 10 CFR Part 50,
Appendix B, quality assurance program. This assurance is achieved by identifying the critical
characteristics of the relays and verifying their acceptability by inspections, tests, or analyses
performed by the purchaser or third-party dedicating entity. For over two decades, the nuclear
industry has been applying the CGD process to Allen Bradley 700-RTC time delay relays for
use in safety-related applications at various nuclear facilities. At some point in time, the design
of the Allen Bradley 700-RTC time delay relay was changed by the original equipment manufacturer (OEM) in order to replace a solid-state integrated circuit logic chip with a CPLD.
This design change introduced the potential for new failure mechanisms such as greater
susceptibility to electrical noise, and may have invalidated the relays ability to meet certain
critical characteristics (e.g., no inadvertent change in state).
This event highlights the challenges that occur when dedicating entities rely, without proper
verification, on commercial OEMs design controls, such as a part number, to conclude that
internal components have remained unchanged. The CGD process of the modified relays
performed by various dedicating entities failed to detect the design change described above, which prevented evaluating its impact on the safety of the affected plants as required by
Criterion III, Design Control of 10 CFR Part 50 Appendix B and 10 CFR Part 50.59, Changes, tests and experiments. As a result, the CGD of the modified relays did not identify and
address the new failure mechanisms associated with the design change. According to the
related 10 CFR Part 21 notifications submitted to the NRC, the design change was not detected
by the dedicating entities because the part number and the external physical dimensions of the
relays remained the same. Both GL 1989-02 and GL 1991-05 referenced above, state that
reliance on part number verification and certification documentation is insufficient to ensure the
quality of procured products.
The references mentioned in the background section of this IN provide additional information
associated with the development, selection, and testing of important critical characteristics when
utilizing a CGD process.
CONTACT
This IN requires no specific action or written response. Please direct any questions about this
matter to the technical contacts listed below or the appropriate Office of Nuclear Reactor
Regulation or Office of New Reactors project manager.
/RA/ /RA/
Michael C. Cheok, Director Lawrence E. Kokajko, Director
Division of Construction Inspection Division of Policy and Rulemaking
and Operational Programs Office of Nuclear Reactor Regulation
Office of New Reactors
Technical Contacts: Samir Darbali, NRR/DE/EICB Alfred Issa, NRO/DCIP/IGCB
301-415-1360 301-415-5342 E-mail: Samir.Darbali@nrc.gov E-mail : Alfred.Issa@nrc.gov
Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under NRC Library.
ML15295A173 *e-mail concurrence TAC MF6983 OFFICE Tech Editor* NRR/DE/EICB/TL NRO/DCIP/IGCB/TL NRR/DE/EICB/BC
NAME CHsu SDarbali* AIssa* MWaters*
DATE 10/15/15 11/09/15 11/9/15 12/4/15 OFFICE NRO/DCIP/IGCB/BC NRR/DE/D NRR/DPR/PGCB/PM NRR/DPR/PGCB/BC
NAME BAnderson* MBailey (Acting)* TMensah SStuchell*
DATE 11/25/15 12/14/15 12/14/15 12/14/15 OFFICE NRR/DPR/PGCB/LA NRO/DCIP/D NRR/DPR/DD NRR/DPR/D
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DATE 01/07/16 02/ 9 /16 02/ 10 /16 02/ 17 /16