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Nei'S Presentation Slides for Public Meeting on Endorsement of NEI 96-07, Appendix D, June 25, 2019
	ML19170A321
Person / Time
Site:	Nuclear Energy Institute
Issue date:	06/19/2019
From:	; Nuclear Energy Institute
To:	; Division of Inspection and Regional Support
	Govan T, 415-6197, NRR/DIRS
References
	NEI 96-07
	Download: ML19170A321 (26)
	v • d • e

NEI 96-07 Appendix D Criterion 6 Examples June 25, 2019

Examples Will Show:

Sec. 4.3.6 of Appendix D is consistent with NEI 96-07, R1 Two decades of implementation Developed with NOPR and 1999 Final Rule SOC in mind Logic and treatment of Criterion 6 is consistent with the application of other 10 CFR 50.59 Evaluation criteria Sec. 4.3.6 of Appendix D avoids uneven application of 50.59 Consistent with NEI 96-07, R1 Consistent with NRCs Reliability Principle of Good Regulation Supports NRC focus on risk-significant issues

Examples for Discussion Instrument Air Compressor Digital Controls Diesel Generator Jacket Water Surge Tank Level Control Containment Fan Coolers Digital Controls Digital Feedwater Control System As time allows:

Feedwater Debris Strainer

Instrument Air (IA) Compressor Digital Controls The Instrument Air system provides compressed, filtered and regulated air in support of various plant needs.

Compressed air is supplied to the IA system by three 50% capacity (405 scfm), oil-free, reciprocating air compressors, each with its own after-cooler, moisture separator and air receiver.

When Instrument and Station Air Systems are separated, only two of the three IA compressors are required to supply the IA header requirements for both units.

Instrument Air Compressor Digital Controls Example Plant UFSAR

Instrument Air Compressor Digital Controls UFSAR Proposed Activity The IA compressors discharge Install new IA compressors with to an IA header which is digital controls common to both units. Likelihood of SCCF of all FMEA: 2 of 3 IA compressors compressors not sufficiently are required during normal ops; low = 0 of 3 compressors low P in the supply line auto Possible loss of normal starts standby IA compressors feedwater event Safety analyses: assume loss of the Instrument Air System

IA Compressor Digital Controls Scenario UFSAR 3.12 Safety SA current different Description Analyses new result?/LAR?

Plant 1 - NEI 2/3 0/3 Loss of IA system No Normal assumed to Feedwater fail (no (LONF) change)

Plant 2 - NEI No existing LONF No change No description Plant 1 - NRC 2/3 0/3 LONF No change Yes Plant 2 - NRC No existing LONF No change Not Clear description

IA Compressor Digital Controls Illustrates Appendix Ds approach is consistent with NEI 96-07, Rev. 1

using the safety analysis level Appendix Ds approach supports NRC focus on risk-significant issues

The NRCs approach appears to require LARs for a lot of very reasonable and benign modifications.

Diesel Generator (D/G) Jacket Water Surge Tank Level Control Diesel generator supplies power to required emergency loads

D/G needs jacket water supply in order to perform its design function Two 100% redundant trains Surge tank is described as having a manual-operated supply and drain, along with various alarms and a high temperature D/G trip

Low level alarm actuates at 200 gallons remaining in a 450 gallon surge tank

Drain line averages 5 GPM Effect of operator error on surge tank draining is discussed

D/G Jacket Water Surge Tank Level Control

D/G Jacket Water Surge Tank Level Control UFSAR Proposed Activity One D/G train operates Replace manual control with FMEA: low water makeup digital controllers and air-water replaces losses operated valves Safety analyses: assume single Likelihood of SCCF of both failure; one train operates controllers not sufficiently low

= 0 of 2 D/G FMEA would examine losing both trains Safety analyses would reflect FMEA outcome

D/G Jacket Water Surge Tank Level Control - new/revised FMEA Procedures already exist for:

Local operator monitoring of D/G operation

Response to Low Surge Tank alarms MCR Trouble Alarm typically points to a local panel

Operator manipulation of surge tank supply and drain valve 40 minutes (200 gallons being drained at 5 GPM) are available after alarm generation Operator complies with procedural guidance Surge tank function is preserved D/G design function is preserved

D/G Jacket Water Surge Tank Level Con.

Scenario UFSAR 3.12 Safety SA current different Description Analyses new result?/LAR?

Plant 1 - NEI Detailed D/G At least one No FMEA Operation D/G operates (no change)

Plant 2 - NEI No existing D/G No change No description Operation Plant 1 - NRC Detailed D/G No change Yes FMEA Operation Plant 2 - NRC No existing D/G No change Not Clear description Operation

D/G Jacket Water Surge Tank Level Control Illustrates Appendix Ds approach produces a consistent answer independent of UFSAR detail, avoiding uneven application

NRCs approach appears to differ based upon level of UFSAR detail (reinstates problem of uneven application)

NRCs approach is not clear for plants with no existing UFSAR description Appendix Ds approach is consistent with NEI 96-07, Rev. 1

Both developed with NOPR and 1999 Final Rule SOC in mind

Revised FMEA = The result of the logically required operator actions in response to the effect of the level controllers failure is the preservation of the D/Gs function ©2019 Nuclear Energy Institute 14

Containment Fan Coolers Digital Controls Limits the containment ambient temperature during normal plant operating conditions Reduce containment ambient temperature and pressure following a Loss of Coolant Accident (LOCA) or a Main Steam Line Break (MSLB) inside containment Provides mixing of the sprayed and unsprayed regions of the containment to improve airborne fission product removal Provides a mixed atmosphere for hydrogen control Five containment fan coolers provided

Containment Fan Coolers Digital Controls

Containment Fan Coolers Digital Controls UFSAR Proposed Activity 2 of 5 coolers required to Install digital controls for each operate following a DBA containment fan cooler FMEA: at least two operable Likelihood of SCCF of all fan coolers has no effect on the coolers "not sufficiently low = 0 Containment Heat Removal of 5 coolers following a DBA System Calculation that used the cooling Containment pressure safety rate produced by two fan coolers analyses: two coolers assumed revised to using a value of zero to operate (0)

Containment Fan Coolers Digital Controls Scenario UFSAR 3.12 Safety (vi) different (vii) DBLFPB LAR?

Analyses result? exceeded or altered?

Plant 1 - 2/5 0/5 Ctmt Yes - SA No - SA Yes NEI coolers Press. Acc. Crit. Acc. Crit.

NOT Met Met Plant 2 - No existing Not No No No NEI description Credited Plant 1 - 2/5 0/5 Ctmt Yes No Yes NRC Coolers Press.

Plant 2 - No existing Not Not Clear No Not Clear NRC description Credited

Containment Fan Coolers Digital Controls Illustrates Appendix Ds approach produces a consistent answer independent of UFSAR detail, avoiding uneven application

NRCs approach appears to differ based upon level of UFSAR detail (reinstates problem of uneven application)

NRCs approach is not clear for plants with no existing UFSAR description Appendix Ds approach focuses on the same safety analysis as criterion 7, but with differing assumptions

Criterion 6: to create a possibility, assume SCCF (0/5 coolers)

Criterion 7: to reflect performance as designed, assume single failure (at least 2/5 coolers) ©2019 Nuclear Energy Institute 19

Digital Feedwater Control System Main Feedwater Regulating Valves (MFRV) and Bypass Feedwater Regulating Valves (BFRV) automatically control feedwater flow and maintain steam generator water level.

The Steam Generator Water Level Control System (SGWLCS) establishes and maintains the steam generator water level within predetermined limits during normal operating transients. The SGWLCS also maintains the steam generator water level within predetermined limits and unit trip conditions.

Digital Feedwater Control System UFSAR Proposed Activity A switchover from the BFRVs to Install digital controls to use the the MFRVs is initiated manually BFRV alone, the MFRV and by the operator at approximately BFRV in parallel, or the MFRV 25 percent power alone to automatically control UFSAR Section 15.1.2, feedwater flow as power level Feedwater System changes.

Malfunctions that Result in an Possible increase in feedwater Increase in Feedwater Flow, flowrate in two loops due to both considers the full opening of the MFRVs and BFRVs going one feedwater regulating valve fully open.

Digital Feedwater Control System The reanalysis of the hot full power case feedwater malfunction event in one loop demonstrated that the results and conclusions discussed in UFSAR Section 15.1.2 are acceptable with the proposed change and assuming a SCCF. An analysis of a hot full power case feedwater malfunction event in two loops was also performed and also demonstrated that the results and conclusions discussed in UFSAR Section 15.1.2 for the hot full power case for one loop are also satisfied. Specifically, the peak heat flux does not exceed 118 percent of its nominal value, and the DNBR remains above the design DNBR limit of 1.24/1.23. Additionally the RCS pressure remains below 110%

of RCS design pressure.

Digital Feedwater Control System Scenario UFSAR 3.12 Safety SA current different Description Analyses new result?/LAR?

Plant 1 - NEI 1 con/ loop Increase in 1 FRV full No - SA Acc.

1 con/ 2 loops FW Flow open 4 Crit. Met FRV full open (2 MFRV & 2 BFRV)

Plant 2 - NEI No existing Increase in See above No - SA Acc.

description FW Flow Crit. Met Plant 1 - NRC 1 con/ loop Increase in See above Yes 1 con/ 2 loops FW Flow Plant 2 - NRC No existing Increase in See above Not Clear description FW Flow ©2019 Nuclear Energy Institute 23

Digital Feedwater Control System Illustrates Appendix Ds approach is consistent with NEI 96-07, Rev. 1

using the safety analysis level Appendix Ds approach produces a consistent answer independent of UFSAR detail, avoiding uneven application

Consistent with NRCs Reliability Principle of Good Regulation

Supports NRC focus on risk-significant issues

Criterion 6 - Four Major Points

1. NEI 96-07, Definition 3.9, malfunction of an SSC important to safety is used within Section 4.3.6 of Appendix D consistently

2. The rulemaking record is clear - the rules intent to identify a different result is to examine the safety analyses

3. Consistent with NEI 96-07, Rev. 1, Section 4.3.6 of Appendix D avoids uneven application of 10 CFR 50.59

4. Section 4.3.6 of Appendix D is consistent with the other 10 CFR 50.59 Evaluation criteria

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