ML18289A980

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October 17, 2018 Open Phase Condition Public Meeting- TSTF Slide Presentation
ML18289A980
Person / Time
Issue date: 10/17/2018
From: Mann B
Technical Specifications Task Force
To: Jessie Quichocho
NRC/NRR/DE/EEOB
Perkins L
Shared Package
ML18309A226 List:
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Download: ML18289A980 (21)
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Technical Specifications Task Force TSTF A Joint Owners Group Activity Industry Evaluation of Open Phase Condition Technical Specification Requirements Brian Mann TSTF Program Manager 1

Technical Specifications Task Force TSTF A Joint Owners Group Activity Technical Specifications Task Force (TSTF)

  • The TSTF is a joint activity of the

- Pressurized Water Reactor Owners Group (PWROG)

Licensing Committee

- Boiling Water Reactor Owners' Group (BWROG) Licensing Committee

- AP1000 Owners Group (APOG)

  • The TSTF works for all nuclear utilities in the US on generic Technical Specifications (TS) issues
  • The TSTF frequently supports NEI committees 2

Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Evaluation

- Periodic tests, calibrations, setpoint verifications or inspections (as applicable) must be established for any new protective features. The surveillance requirements must be added to the plant Technical Specifications if necessary to meet the provisions of 10CFR50.36. Further industry guidance will be provided for the development of Technical Specifications as the design features are identified.

  • In 2015, the NEI OPC Working Group requested that the TSTF evaluate whether the planned OPC detection and mitigation equipment satisfied any of the regulatory criteria for inclusion in the TS.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Evaluation

  • The TSTF developed a position paper that was reviewed and commented on by the PWROG and BWROG Licensing Committee, the APOG, and the NEI OPC Working Group.
  • Following comment resolution, the document was published on October 8, 2015 and distributed to the Owners Group members and NEI.

- The paper was provided to the NRC on 9/7/18 (ML18262A377)

  • This paper is the basis for evaluations by utilities on whether TS changes are needed when installing OPC equipment.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • The Position Paper considered two simplified designs:

- Devices on the high side of the preferred power supply (Location A),

- Devices on the ESF Buses (Location B).

  • Both designs alert the operator in the control room to an OPC and separate the onsite power distribution system from the affected offsite source.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • There is an important distinction between designs:
  • In most designs, the OPC equipment only separates the onsite power distribution system from the affected offsite source, initiating the existing undervoltage detection systems to start and load the emergency onsite power source.

- This design was evaluated in the position paper.

  • In some designs, the OPC equipment interfaces directly with the engineered safety features actuation logic, bypassing the existing undervoltage function.

- This design likely meets 10 CFR 50.36(c)(2)(ii), Criterion 3.

- Some plants installing this design have already submitted amendments adding the OPC function to the TS.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • In evaluating whether the OPC detection and mitigation system satisfies any regulatory requirement to be included in the TS, the TSTF considered:

- The 1968 revision to 10 CFR 50.36, "Technical Specifications;"

- The Atomic Energy Commission (AEC) 1968 "Guide to Content of Technical Specifications for Nuclear Reactors;"

- The May 9, 1988 letter from Thomas E. Murley (NRC) to the Owners Group chairmen that documents the NRC staff's conclusions regarding the current standard Technical Specifications requirements that must be retained in plant Technical Specifications;

- The NRC's "Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors," 58 FRN 39132, July 22, 1993;

- The 1993 revision to 10 CFR 50.36 to include the four criteria for selecting limiting conditions for operation (LCOs);

- The October 25, 1993 letter from William T. Russell (NRC) to the Owners Groups chairmen, "Content of the Standard Technical Specifications, Section 5.0, Administrative Controls;" and

- The improved Standard Technical Specifications (STS) for nuclear power reactors (NUREG-1430 through NUREG-1434), originally published in 1993 and revised in 1995, 2001, 2004, 2005, and 2011.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • Important considerations:

- The STS definition of "operability" states that a system is operable when, among other requirements, the required normal or emergency electric power is available.

- The AC power sources provide required power to shut down the reactor and maintain it in a safe shutdown condition after an AOO or DBA.

  • The function of the OPC equipment is to support the performance of the safety function of the offsite power sources by monitoring and separating an inoperable offsite source.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • The position paper determined that the OPC equipment did not meet the requirements for :

- A Safety Limit, Limiting Safety System Setting, Design Feature, or Administrative Control

  • Evaluating the four criteria for LCOs in 10CFR 50.36 using the guidance in the NRC's Final Policy Statement, the OPC detection and mitigation equipment did not meet the requirements of Criterion 1, 2, or 4.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • The OPC equipment supports offsite power. Offsite power meets Criterion 3, "A structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier."
  • The LCO 3.8.1 and 3.8.2 Bases state than an operable offsite source must be capable of maintaining rated frequency and voltage, and accepting required loads during an accident, while connected to the ESF buses.
  • The OPC equipment functions to monitor the offsite sources and separate offsite sources are not capable of accepting required loads during an accident. Therefore, it is a support system for the offsite sources, but does not satisfy Criterion 3.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • There are many support systems for offsite power sources, such as:

- transformer pressure trip devices,

- breaker monitoring and trip devices, and

- devices on the transmission network.

  • These support systems are not included in the TS. However, the effect of the failure of these support systems on the operability of the offsite sources is addressed under the stations operability determination process.
  • The existing LCO 3.8.1 and LCO 3.8.2 operability requirements for the offsite sources encompasses the OPC support function, as the definition of "operability" includes necessary instrumentation and controls.
  • The OPC equipment itself does not meet Criterion 3, but it supports AC Sources which do meet Criterion 3.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

- Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met.

- Verify correct breaker alignment and indicated power availability for each [required] offsite circuit.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

- "This SR ensures proper circuit continuity for the offsite AC electrical power supply to the onsite distribution network and availability of offsite AC electrical power."

  • An OPC is created when there is not proper circuit continuity or breaker alignment for one or more phases of an offsite source. The existing SR 3.8.1.1 verifies an OPC does not exist.
  • The switchyard currently contains protection features to address faults. This equipment is not described in the TS or TS Bases. The OPC equipment should be treated similarly.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper

  • In the STS, SRs confirm that a function is available and do not typically specify the equipment to be used to perform the verification.
  • Note that SR 3.0.1 requires Surveillance Requirements to be met at all times.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity OPC Position Paper Conclusion

  • The regulations and regulatory guidance do not require additional TS requirements on the OPC detection and mitigation equipment unless the OPC equipment interfaces directly with the engineered safety features actuation logic, bypassing the existing undervoltage function.

- The existing LCO 3.8.1, LCO 3.8.2, and SR 3.8.1.1 on offsite sources require offsite circuits are operable and an OPC to not be present.

- The OPC equipment is a non-TS support system to the offsite AC power sources.

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Technical Specifications Task Force TSTF A Joint Owners Group Activity Response to NRC Questions

  • If OPIS protection components support mitigation of DBA should it be in Tech Specs?

- OPIS protection would be included in the TS if it satisfies one of the criteria in 10 CFR 50.36

- As stated in the presentation, OPIS does not satisfy any of the 10 CFR 50.36 criteria and should not be included in TS

  • Can we provide an example of another system or component that is not in tech specs that performs support functions similar to OPIS?

- There are many non-TS support systems that support TS functions, such as room and pump coolers, overcurrent protection, transformer protective functions, barriers, doors, circulating water screens, etc. 16

Technical Specifications Task Force TSTF A Joint Owners Group Activity Response to NRC Questions

  • Are there other support systems that are captured in operability determinations but are not in TS surveillance requirements? Example of other equipment that is a support and used to support operation but not in Surveillance Requirements?

- Yes. All of the systems listed before. For example, room coolers have no TS SR, but are required support functions for most pumps 17

Technical Specifications Task Force TSTF A Joint Owners Group Activity Response to NRC Questions

  • Explain the history of the TSTF & Bases changewhat was recommended; why/when that changed- i.e. story of traveler.

- The position paper recommended clarification of the TS Bases to describe the support function performed by the OPC equipment and to clarify that indicated power availability includes all three phases as assumed in the analyses

- After further consideration, it was determined that describing the OPC equipment in the TS Bases was inappropriate because other switchyard protective equipment is not described in the TS Bases, and the TS Bases do not typically describe the equipment used to perform an SR 18

Technical Specifications Task Force TSTF A Joint Owners Group Activity Response to NRC Questions

- TSTF-556-T, "Modify TS 3.8.1 and TS 3.8.2 Bases to Address an Open Phase Condition," was originated in January 2016

- The primary purposes of the traveler were to:

  • Provide guidance to licensees that a description of the OPC mitigation system should not be added to the Bases, as it would be inconsistent with the treatment other offsite power protective features

- The traveler was distributed to the PWROG, BWROG, and NEI OPC Task Force for comment

  • The significant comments were:

- Rewording the SR 3.8.1.1 Bases to more closely resemble the SR, and

- Remove justification discussions that were not generic 19

Technical Specifications Task Force TSTF A Joint Owners Group Activity Response to NRC Questions

- Following resolution of the comments, it was approved by the TSTF and distributed to the licensees use on May 2, 2016

- Note that adoption of Travelers is voluntary

- The TSTF does not track adoption of Bases-only changes 20

Technical Specifications Task Force TSTF A Joint Owners Group Activity Questions?

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