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 Attachment 2 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.

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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

• Calc Th/Tq Close - 5685 lbs

• Safety Function - Open/Close

• Calc Th/Tq Open - 8250 lbs

• Manufacturer - Westinghouse

• Least Available - 8500 lbs

• Valve Type - Flex Wedge

• Th/Tq Dyn Close - 6200 lbs

• Valve Size - 4

• Th/Tq Dyn Open - 8700 lbs

• Actuator Make - Limitorque

• Meas Close VF - 0.5

• Actuator Size - SMB-000

• Meas Open VF - 0.47

• Risk - Medium

• Meas LSB - 9.5%

• DB Pressure C/O - 105 / 105

• Margin Close - 5%

• Assumed VF C/O - 0.3 / 0.3

• Margin Open - 3.2%

• Assumed LSB - 5%

• Basis - Extrapolated test &

• Assumed SFC - .12 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 One month before On-site activities Three months before the inspection, the begin, valves the inspection team leader visits the analyzed and begins, the licensee site to coordinate the program assessed.

receives a data inspection and obtain Two weeks on site, request regarding 30 test data for 8-12 one week office valves review Issues reviewed by Exit meeting held, Report issuance- regional preliminary estimated 45 days management and observations and after exit meeting nationwide finding findings presented review panel 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