ML20003F667

POV Workshop Region IV Jan 2020

ML20003F667
Person / Time
Issue date:	01/03/2020
From:	Douglas Bollock, Kenneth Kolaczyk, Thomas Scarbrough NRC/NRR/DRO/IRIB
To:
Bollock D, 415-6609, NRR/DRO
References
Download: ML20003F667 (22)

Text

Inspection Procedure 71111.21N Power-Operated Valve Inspection Public Workshop Douglas Bollock, Kenneth Kolaczyk, Thomas G. Scarbrough, U.S. Nuclear Regulatory Commission January 9, 2020

POV Public Meeting Agenda

• Discuss why we are inspecting POVs

• Review of the POV inspection procedure requirements and guidance

• Overview of EQ inspection lessons learned

• Review questions we have received (FAQ)s

• Mock POV scenario discussion

• Question and answer period 2

Why Are We Inspecting POVs Now?

• Baseline inspection efforts do not examine all POV program attributes described in Generic Letter 96-05

• Operating experience indicates POV/MOV performance gaps still exist:

- Browns Ferry Unit 1, October 23, 2010, Stem Disc Separation

- LaSalle Station Unit 2, February 11, 2017, Wedge Pin and Stem Disc Separation 3

POV Procedure and Guidance 4

IP 71111.21N.02 Objective

• IP 71111.21.02 (July 26, 2019), Design-Basis Capability of Power-Operated Valves under 10 CFR 50.55a Requirements, specifies that the objective is to: assess the reliability, functional capability, and design basis of risk-important POVs as required by 10 CFR 50.55a and applicable 10 CFR Part 50, Appendix A and Appendix B.

5

General Guidance Section 02.01 Sample Selection

• As a pre-inspection activity, inspectors will select 30 POVs:

- Multiple systems and different valve types (MOVs, AOVs, HOVs, SOVs, and Squib Valves (as applicable), sizes and manufacturers

- Risk assessment

- Historical performance

• The Inspectors will request the licensee to make available:

- Design-basis capability information including function, safety significance, sizing, margin, and setting assumptions

- See Appendix C to the POV inspection procedure 6

General Guidance Section 02.01 Sample Selection

• Based on POV design-basis capability information, the inspectors will consider the following for selection of a 10 POV sample for detailed inspection review:

- System Risk

- POVs with high incidence of corrective maintenance and/or poor performance

- POVs with low margin

- POVs with questionable assumptions (e.g., low VF, low friction values, not all uncertainties captured)

- POVs in untreated water systems

- POVs in high energy systems

- POVs located in elevated environments (e.g., high temperature, high radiation areas) 7

Inspection Preparation Activities

• Discuss inspection with site POV engineers and obtain information (such as POV capability calculations and assumptions)

• Evaluate POV parameter assumptions for potential issues

• Determine the basis of POV assumptions (such as EPRI, JOG, ComEd) and whether the conditions for each source are correctly applied 8

Typical Sample Gate Valve Data Sheet Valve ID SI-123 Safety Function - Open/Close Manufacturer - Westinghouse Valve Type - Flex Wedge Valve Size - 4 Actuator Make - Limitorque Actuator Size - SMB-000 Risk - Medium DB Pressure C/O - 105 / 105 Assumed VF C/O - 0.3 / 0.3 Assumed LSB - 5%

Assumed SFC -.12 Calc Th/Tq Close - 5685 lbs Calc Th/Tq Open - 8250 lbs Least Available - 8500 lbs Th/Tq Dyn Close - 6200 lbs Th/Tq Dyn Open - 8700 lbs Meas Close VF - 0.5 Meas Open VF - 0.47 Meas LSB - 9.5%

Margin Close - 5%

Margin Open - 3.2%

Basis - Extrapolated test &

revised calc 9

What Should Licensees Be Concerned With?

• For All Valves

- Assumed friction coefficient is less than bounding values (0.2 stem-to-stem nut friction for gate, globe and 0.6 bearing coefficient for bronze bearings on butterfly valve)

- As left valve settings near structural limits

- Misapplication of EPRI MOV PPM data and methodology

- Using EPRI MOV PPM test data to justify valve factor assumptions in valve capability calculations

- Using static testing as basis for monitoring valve degradation with no engineering analysis or data 10

Inspection Process Flow Three months before the inspection begins, the licensee receives a data request regarding 30 valves One month before the inspection, the team leader visits the site to coordinate the inspection and obtain test data for 8-12 On-site activities begin, valves analyzed and program assessed.

Two weeks on site, one week office review Exit meeting held, preliminary observations and findings presented Issues reviewed by regional management and nationwide finding review panel Report issuance-estimated 45 days after exit meeting 11

EQ Inspection Lessons Learned 12

EQ Inspection Takeaways

• EQ inspection procedure could have benefited from further background guidance

• Inspectors had difficulty interpreting each nuclear power units unique EQ licensing basis

• Communication between inspectors and NRR technical program office not consistent

• The minor, more than minor screening criteria contained in current NRC guidance was not as helpful in assessing specific EQ related issues 13

POV Inspection Enhancements

• Identified singular technical and programmatic points-of-contact within the NRC

• Minor/more-than-minor examples developed

• Enhanced training for inspectors was developed(both technical and inspection implementation focused)

• Enhanced Interactive SharePoint Site developed.

• Tabletop dry runs performed

• Findings review panel established proactively 14

FAQs

• Q: What has been communicated to stakeholders?

• A: ROP monthly public meetings since May 2019

- POV inspections replacing EQ inspections beginning in January 2020

- NRC incorporated lessons learned from EQ inspection implementation 15

FAQs

• Q: What is publicly available in regards to POV material?

• A: Publicly available now:

- Inspection Procedure IP71111.21N.02 (ML19067A240)

- MOV technical training (ADAMS Package: ML19235A1212020)

- EQ lessons learned (ML19183A063) 16

FAQs

• Q: What is publicly available in regards to POV material?

• A: Public availability forthcoming:

- POV Inspection implementation training

- Minor/More-than-minor examples specific to POVs (as an appendix to the IP) 17

FAQs

• Q: What are the NRC resources uses per POV inspection?

• A: 3 NRC inspectors, 2 weeks onsite

- 210 hrs (+/- 32 hrs)

- No use of contract inspectors planned 18

FAQs

• Q: Will there be other public workshops?

• A: The NRC staff has now held two public workshops on POV inspections.

- Staff is open to more as needed and will consider any input received today.

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Scenario Discussions

• Scenario one:

- Service water/emergency service water isolation valve testing

• Scenario two:

- Block valve design assumptions 20

Q & A Session 21

For additional information, contact Doug Bollock Douglas.Bollock@nrc.gov Ken Kolaczyk Kenneth.Kolaczyk@nrc.gov Tom Scarbrough Thomas.Scarbrough@nrc.gov Mike Farnan Michael.Farnan@nrc.gov 22