ML18241A369
ML18241A369 | |
Person / Time | |
---|---|
Issue date: | 08/30/2018 |
From: | Joseph Holonich NRC/NRR/DLP/PLPB |
To: | |
Holonich J, NRR/DLP, 415-7297 | |
References | |
Download: ML18241A369 (24) | |
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ENTRY CRITERIA FOR THE OPERABILITY DETERMINATION PROCESS NRC PUBLIC MEETING August 30, 2018
© NEI © 2018. 2018All rights NEI. Allreserved.
rights reserved.
Purpose
- Describe the Entry Criteria for the Operability Determination Process
- Examples will be used for:
Illustrating each of the criteria Integrated examples to illustrate the entire process
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Background===
- At a RUG III workshop held in May 2015, Operability Determination Process issues that were commonly encountered were discussed
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Inconsistencies in Current Guidance
- Inspection Manual (IMC) 0326 is not consistent in defining the conditions that warrant an Operability Determination
- IMC-0326 uses the following terms to describe the conditions when an Operability Determination should be performed:
- Page 1- reasonably indicating a degraded or nonconforming condition
- Page 6 - Potential degraded/nonconforming conditions
- Pages 5 & 8 - Actual degraded/nonconforming conditions
- Page 6 - Presumption of operability has been lost
- Pages 5 & 8 - Operability called into question
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Current Industry Situation
- Typical site performs some type of Operability Assessment roughly two to ten times per day or more
- ODP entry occurs thousands of times per year
- Includes any assessment of an SSCs functional capability
- Rarely, if ever, is a previously undetected inoperability uncovered
- The proposed revision to the ODP entry criteria is intended to address this situation
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Industry Solution
- NEI process defines the entry criteria of the Operability Determination Process based on the Technical Specification definition of Operability
- Definition of Operable solely addresses functions
- Operability is the responsibility of the licensee
- The Operability Process will be entered when all of the Three Required Criteria are satisfied
- SROs always will retain the option of requesting ODs
- All conditions continue to be assessed
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Three Required Criteria
- 1. The deficient condition must affect a TS SSC installed in an operating unit.
o a specified safety function or o a required and necessary support function
- 2. The deficient condition must have a functional impact on the SSC. This includes the ability to perform required functions under postulated, off-normal design conditions.
- 3. The functional impact of the deficient condition must be substantive (i.e. non-trivial).
- Substantive means:
o The functional impact is observable or o The deviation from as-designed values is more than 10%
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First Criterion The deficient condition must affect a TS Comments/Details SSC installed in an operating unit. Includes the SSCs design, which will involve engineering. Practically, it is A TS SSC is an SSC that has a functional most commonly:
impact on either:
- Calculations
- a specified safety function or
- Purchase and/or design specifications
- a required and necessary support Documentation deficiencies that may function result in altered design requirements to possibly allow for either purchase of a different SSC or altered operation.
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Examples That Would Not Satisfy the First Criterion
- Vendor information associated with an SSC not installed
- Design information errors with no potential for either altering a design specification or the SSCs operation
- For example, drawing or database errors
- Procedure formatting issues
- An SSC with no relationship to any specified safety function or a required and necessary support function
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Examples That Would Satisfy the First Criterion
- Procedure issues that involve the execution of procedural steps, including procedural quality and/or completeness
- An SSC with any relationship to any specified safety function or a required and necessary support function
- A problem with a TS SSC has been discovered at a similar site within the nuclear industry. The problems presence has been confirmed on the unit.
- Design information errors with a potential for either altering a design specification or the SSCs operation
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Second Criterion The deficient condition must have a Comments/Details functional impact on the SSC. This includes If this Criterion is not satisfied, it the ability to perform required functions describes issues that provide no direct under postulated, off-normal design evidence regarding the functional conditions. status of an installed SSC.
No direct evidence is intended to mean:
- There is no observable functional effect under any condition.
- No evidence or indication that a functional impact would be manifest under off-normal/accident conditions.
Situations that could represent a problem indicate the need for further investigative work rather than an OD.
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Examples That Would Not Satisfy the Second Criterion
- The absence of an aspect of Quality Assurance does not mean that a functional problem is present. (Could versus Does)
- Deficiencies in design of non-TS testing programs. (e.g.
Preventative testing program does not follow vendor recommendations.)
- Deficient and/or missing radiographs of welds
- Minor deficiencies in design documentation, including missing calculations.
- No indication of functional issues associated with:
- Non-safety-related SSCs (e.g.. Commercial grade gaskets) installed in safety-related applications
- Issues initiated by the 10 CFR 21 process
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Examples That Would Satisfy the Second Criterion
- Design documentation deficiencies that result in altered requirements
- Any indication of functional issues associated with:
- Non-safety-related SSCs (e.g.. Commercial grade gaskets) installed in safety-related applications
- Issues initiated by the 10 CFR 21 process with indication of functional issues
- Procedure deficiencies that would prevent successful performance of a required TS function
- Megger reading of a motor winding deviating from design values
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Examples That Would Satisfy the Second Criterion
- Missing washers and/or wrong size nuts on a pipe hanger
- Corrosion on a structural steel member
- An SSC has exhibited a reduction in reliability that exceeds the site-specific monitoring standards In every instance, the common thread is that the issue reflects some type of actual problem with an installed TS SSC.
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Third Criterion The functional impact of the deficient Comments/Details condition must be substantive (i.e. non- This Criterion acknowledges that SSCs trivial). are designed, licensed, and installed
- Substantive (more than trivial) means: with substantial margins. It includes consideration of design errors resulting
- The functional impact is observable in functional impact.
or; If not satisfied, the issue would have the
- The deviation from as-designed following characteristics:
values is more than 10%
- The issue is manifest at functional level beneath that described in the UFSAR
- There is no functional effect observable under any condition
- No evidence or indication that a functional impact would be manifest under off-normal/accident conditions.
- If the installed margin is amenable to an estimate, the margin loss is estimated to
© NEI 2018. All rights reserved. be approximately 10% or less 15
Examples That Would Not Satisfy the Third Criterion
- Megger reading of a motor winding deviating by less than 10%
from design
- No unexplained motor symptoms
- Non-compliance with a code of construction (excluding ASME code class 1) of less than 10%
- Deviation from a parameter specified by the design, including EQ-related, by 10% or less
- Calculation error with results deviating by 10% or less
- For example, timing of safety injection timing did not properly account for loading of condensate pumps. Total condensate pump load is less than 10% of transformer design loading
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Examples That Would Satisfy the Third Criterion
- Cut electrical or instrument cable
- Any indication of functional issues associated with:
- Non-safety-related SSCs (e.g.. Commercial grade gaskets) installed in safety-related applications
- Issues initiated by the 10 CFR 21 process
- Missing or improper pipe hanger components with local indication of physical instability
- Megger readings deviating from design values by more than 10%
- Calculation error with results deviating by 10% or more
- e.g. Timing of safety injection timing did not properly account for loading of condensate pumps Total condensate pump load is more than 10% of transformer design loading
© NEI 2018. All rights reserved. 17
Summary Flowchart The deficient condition must affect a TS SSC installed in an operating unit.
A TS SSC is an SSC that has a functional impact on either:
- a specified safety function or;
- a required and necessary support function The deficient condition must have a functional impact on the SSC. This includes the ability to perform required functions under postulated, off-normal design conditions.
The functional impact of the deficient condition must be substantive (i.e. non-trivial).
All Yes indicates that an Operability Any No indicates that an Operability Determination is Required Determination is Not Required
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Illustration of Examples Non-safety related (NSR) Containment cooler fails Used to maintain containment pressure within specified limits
- 1 #2 #3 Yes No N/A NSR gasket installed in ECCS discharge piping discovered following a plant walkdown identification of a leak
- 1 #2 #3 Yes Yes Yes
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Illustration of Examples (cont.)
Vendor-recommended tests not performed on Safety-Related relays in an ECCS system
- 1 #2 #3 Yes No N/A Vendor-recommended tests on Safety-Related relays in an ECCS system has failed in an undetected manner in the past
- 1 #2 #3 Yes Yes Yes A steam trap that drains the steam supply to the turbine driven AFW pump governor is flooded
- 1 #2 #3 Yes Yes Yes
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Illustration of Examples (cont.)
Important ECCS Operating Procedure steps are out of sequence
- 1 #2 #3 Yes Yes Yes ECCS Operating Procedure steps are vague and could allow improper operation
- 1 #2 #3 Yes No N/A Calculation error found resulting in a required ECCS pump flow increasing from 280 GPM to 290 GPM
- 1 #2 #3 Yes Yes No
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Summary
- The revised entry criteria (Three Required Criteria) provides a more consistent entry process linked to the Technical Specification definition of Operability
- There is no change to the conduct of an ensuing Operability Determination due to the application of the Three Required Criteria
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Look Ahead
- The next meeting will focus on the NRC providing feedback on the Operability Determination Process Entry Criteria.
- In a future meeting we will present the definition of Specified Safety Function (SSF)
- The Operability Determination Process is oriented around SSF
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QUESTIONS / DISCUSSION
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