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Category:Reactor Oversight Process (ROP) Archive File
MONTHYEARML20322A3392020-11-17017 November 2020 NEI ROP White Paper Modification of the Description of Unplanned Scrams with Complications for Nov 18 2020 ROP Public Meeting 2020-11-17
[Table view] Category:Report
MONTHYEARML23290A1252023-10-17017 October 2023 NEI - NEI 99-02, Rev. 8, Draft Regulatory Assessment Performance Indicator Guideline ML23290A1472023-10-17017 October 2023 NEI 99-02 Rev 8 Draft 9 29 2023 Redline Version ML23157A1062023-06-0606 June 2023 NEI 19-01, Rev 1, Safety and Economic Benefits of Accident Tolerant Fuel ML23129A0282023-05-0202 May 2023 20230502, NEI Issues for Event Notification Implementation Workshops ML23110A6762023-04-18018 April 2023 04-18-23_NRC_NEI 23-03 Review + Endorse ML23138A1662023-03-24024 March 2023 Transmittal of NEI 22-05 Revision a, Technology Inclusive Risk Informed Change Evaluation (Tirice) Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07 ML23083B4622023-03-24024 March 2023 Transmittal of NEI 22-05 Revision a, Technology Inclusive Risk Informed Change Evaluation (Tirice) Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07 ML23125A3202023-03-0101 March 2023 Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07 Revision a 5-4-23 Tirice Response to NRC Comments ML22298A2282022-10-25025 October 2022 NEI 15-09, Rev. 1, Cybersecurity Event Notifications ML22297A2482022-10-20020 October 2022 NEI Comments on 10-20-2022 CCF Meeting Feedback and Comments ML23072A0632022-09-30030 September 2022 (Draft) NEI White Paper Remediation of Vulnerabilities Identified in CDAs - 08302022R0 ML22195A1692022-07-31031 July 2022 NEI, Draft G of NEI 99-01, Development of Emergency Action Levels for Non-Passive Reactors, Revision 7 - Change Summary ML22195A1672022-07-14014 July 2022 NEI, Draft G of NEI 99-01, Development of Emergency Action Levels for Non-Passive Reactors, Revision 7 ML22195A1682022-07-14014 July 2022 NEI, Marked-Up to Draft G of NEI 99-01, Development of Emergency Action Levels for Non-Passive Reactors, Revision 7 ML22109A2082022-04-0808 April 2022 April 8, 2022, NEI White Paper on Digital Instrumentation and Control Common Cause Policy Considerations Version 2.0 ML22048A5812022-02-16016 February 2022 NEI 22-02: Guidelines for Weather-Related Administrative Controls for Short Duration Outdoor Dry Cask Storage Operations ML22019A2922022-01-12012 January 2022 NEI, Submittal of Proposed Revisions to Aging Management Programs XI.M33, Selective Leaching and XI.E3, Inaccessible Power Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements ML21343A2822021-12-31031 December 2021 Redline/Strikeout Version of NEI 21-07 Rev 0-B, Technology Inclusive Guidance for Non-Light Water Reactors Safety Analysis Report Content for Applicants Using the NEI 18-04 Methodology ML21343A2922021-12-0808 December 2021 NEI, Transmittal of NEI 21-07 Revision 0-B, Technology Inclusive Guidance for Non-Light Water Reactor Safety Analysis Report: for Applicants Utilizing NEI 18-04 Methodology ML21337A3802021-12-0303 December 2021 NEI Technical Report NEI 17-06 - Guidance on Using Iec 61508 SIL Certification to Support the Acceptance of Commercial Grade Digital Equipment for Nuclear Safety Related Applications, Revision 1 ML21305A0012021-11-30030 November 2021 NEI 17-06 Rev 0 Draft B, Guidance on Using Iec 61508 SIL Certification to Support the Acceptance of Commercial Grade Digital Equipment for Nuclear Safety Related Applications (Staff Comments Incorporated ML21342A2032021-10-29029 October 2021 Letter from W. Gross to S. Atack, Endorsement of Nuclear Energy Institute 13-10, Cyber Security Control Assessments, Revision 7, Dated October 29, 2021 ML21342A1682021-10-29029 October 2021 Letter from W. Gross to S. Atack, Endorsement of Nuclear Energy Institute 10-04, Identifying Systems and Assets Subject to the Cyber Security Rule, Revision 3, Dated October 29, 2021 ML21274A0312021-10-0101 October 2021 NRC Draft Detailed Comments Related to NEI 21-07, Revision 0, Technology Inclusive Guidance for Non-Light Water Reactors Safety Analysis Report Content for Applicants Using the NEI 18-04 Methodology ML21278A4722021-09-30030 September 2021 NEI 20-07, Rev. Draft, Guidance for Addressing Common Cause Failure in High Safety-Significant Safety-Related Digital I&C Systems ML21257A2352021-08-19019 August 2021 Rulemaking: Proposed Rule: Advanced Reactor Physical Security, Email Exchange Between Nrc and NEI Draft Pages from NEI-20-05 Rev. E ML21250A3782021-08-0202 August 2021 NEI 21-07, Revision 0, Technology Inclusive Guidance for Non-Light Water Reactors SAR Content for Applicants Using the NEI 18-04 Methodology ML21130A5962021-05-31031 May 2021 NEI, Guidance for Addressing Software Common Cause Failure in High Safety-Significant Safety Related Digital I&C Systems - Draft C ML21130A5972021-05-31031 May 2021 NEI 20-07, Guidance for Addressing Software Common Cause Failure in High Safety-Significant Safety Related Digital I&C Systems - Draft C ML21130A5982021-05-0707 May 2021 NEI Responses to NRC Staff Comments on NEI 20-07 Draft B ML21125A2842021-05-0505 May 2021 Transmittal of NEI 20-09: Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-Light Water Reactor Standard ML21110A0662021-04-20020 April 2021 Nei'S Comparison Table Between NEI 20-07 Sdos and NRC RGs and Endorsed IEEE Stds R2 ML21085A5552021-03-25025 March 2021 NEI 20-09 -Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-LWR PRA Standard, March 2021 ML21089A0902021-03-18018 March 2021 NEI Comments on Renewal of Performance Indicators Information Collection, March 18, 2021 ML21049A0572021-03-0202 March 2021 Rulemaking: Proposed Rule: NRC Markup of NEI-20-05 Draft B Comments on Methodological Approach and Considerations for a Technical Analysis to Demonstrate Compliance with the Performance Criteria of 10 CFR 73.55(a)(7) ML20339A4852020-11-23023 November 2020 NEI 20-09 - NRC Comments Resolved November 2020 ML20322A3392020-11-17017 November 2020 NEI ROP White Paper Modification of the Description of Unplanned Scrams with Complications for Nov 18 2020 ROP Public Meeting ML21050A0902020-08-31031 August 2020 Staff Detailed Comments - NEI 20_07 Draft Revision B -February 2021 ML20245E1472020-08-31031 August 2020 Attachment 1 - NEI Guidelines for the Implementation of the Risk-Informed Process for Evaluations Integrated Decision-Making Panel ML20245E5612020-08-31031 August 2020 Guidance for Addressing Software Common Cause Failure in High Safety-Significant Safety Related Digital I&C Systems ML20302A1152020-08-24024 August 2020 NEI 20-09 - Nlwr PRA Peer Review Rev1 August 2020 ML20211L7142020-07-24024 July 2020 Industry Position Regarding Safety Margin: Dispositioning Degraded or Failed Management Measures Above and Beyond Regulatory Requirements, and Meeting Performance Criteria; Follow Up to May 6, 2020 Letter on Smarter Program Inspection Prior ML20155K6852020-06-0101 June 2020 Availability of NEI 20-09, Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-LWR Standard, for NRC Review and Endorsement ML20154K5662020-06-0101 June 2020 Availability of NEI 20-09, Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-LWR Standard, for NRC Review and Endorsement ML20129J8592020-05-31031 May 2020 NEI 96-07, Appendix D Revision 1, Draft M, May 2020 ML20129J8582020-05-30030 May 2020 NEI 96-07, Appendix D, Revision 1, Draft M, May 2020 with Redline Strike ML20141L7882020-05-20020 May 2020 NEI - Comments on Draft Micro-Reactor Applications COL-ISG-029, Environmental Considerations Associated with Micro-Reactors ML20139A1902020-05-14014 May 2020 05-14-20 Changes to NEI 10-04 and NEI 13-10 Guidance for Identifying and Protecting Digital Assets Associated with Safety-Related and Important-to-Safety Functions ML20134J0332020-05-13013 May 2020 Submittal of Response to Request for Additional Information (RAI) for NEI 14-05A, Revision 1, Guidelines for the Use of Accreditation in Lieu of Commercial Grade Surveys for Procurement of Laboratory Calibration and Test Services ML20135H1682020-05-13013 May 2020 Request for NRC Endorsement of NEI 96-07, Appendix D, Rev 1 2023-06-06
[Table view] Category:Technical
MONTHYEARML23290A1472023-10-17017 October 2023 NEI 99-02 Rev 8 Draft 9 29 2023 Redline Version ML23290A1252023-10-17017 October 2023 NEI - NEI 99-02, Rev. 8, Draft Regulatory Assessment Performance Indicator Guideline ML23157A1062023-06-0606 June 2023 NEI 19-01, Rev 1, Safety and Economic Benefits of Accident Tolerant Fuel ML23110A6762023-04-18018 April 2023 04-18-23_NRC_NEI 23-03 Review + Endorse ML23083B4622023-03-24024 March 2023 Transmittal of NEI 22-05 Revision a, Technology Inclusive Risk Informed Change Evaluation (Tirice) Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07 ML23138A1662023-03-24024 March 2023 Transmittal of NEI 22-05 Revision a, Technology Inclusive Risk Informed Change Evaluation (Tirice) Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07 ML23125A3202023-03-0101 March 2023 Guidance for the Evaluation of Changes to Facilities Utilizing NEI 18-04 and NEI 21-07 Revision a 5-4-23 Tirice Response to NRC Comments ML22298A2282022-10-25025 October 2022 NEI 15-09, Rev. 1, Cybersecurity Event Notifications ML22195A1692022-07-31031 July 2022 NEI, Draft G of NEI 99-01, Development of Emergency Action Levels for Non-Passive Reactors, Revision 7 - Change Summary ML22195A1682022-07-14014 July 2022 NEI, Marked-Up to Draft G of NEI 99-01, Development of Emergency Action Levels for Non-Passive Reactors, Revision 7 ML22195A1672022-07-14014 July 2022 NEI, Draft G of NEI 99-01, Development of Emergency Action Levels for Non-Passive Reactors, Revision 7 ML22048A5812022-02-16016 February 2022 NEI 22-02: Guidelines for Weather-Related Administrative Controls for Short Duration Outdoor Dry Cask Storage Operations ML21343A2822021-12-31031 December 2021 Redline/Strikeout Version of NEI 21-07 Rev 0-B, Technology Inclusive Guidance for Non-Light Water Reactors Safety Analysis Report Content for Applicants Using the NEI 18-04 Methodology ML21343A2922021-12-0808 December 2021 NEI, Transmittal of NEI 21-07 Revision 0-B, Technology Inclusive Guidance for Non-Light Water Reactor Safety Analysis Report: for Applicants Utilizing NEI 18-04 Methodology ML21337A3802021-12-0303 December 2021 NEI Technical Report NEI 17-06 - Guidance on Using Iec 61508 SIL Certification to Support the Acceptance of Commercial Grade Digital Equipment for Nuclear Safety Related Applications, Revision 1 ML21305A0012021-11-30030 November 2021 NEI 17-06 Rev 0 Draft B, Guidance on Using Iec 61508 SIL Certification to Support the Acceptance of Commercial Grade Digital Equipment for Nuclear Safety Related Applications (Staff Comments Incorporated ML21342A1682021-10-29029 October 2021 Letter from W. Gross to S. Atack, Endorsement of Nuclear Energy Institute 10-04, Identifying Systems and Assets Subject to the Cyber Security Rule, Revision 3, Dated October 29, 2021 ML21342A2032021-10-29029 October 2021 Letter from W. Gross to S. Atack, Endorsement of Nuclear Energy Institute 13-10, Cyber Security Control Assessments, Revision 7, Dated October 29, 2021 ML21274A0312021-10-0101 October 2021 NRC Draft Detailed Comments Related to NEI 21-07, Revision 0, Technology Inclusive Guidance for Non-Light Water Reactors Safety Analysis Report Content for Applicants Using the NEI 18-04 Methodology ML21278A4722021-09-30030 September 2021 NEI 20-07, Rev. Draft, Guidance for Addressing Common Cause Failure in High Safety-Significant Safety-Related Digital I&C Systems ML21257A2352021-08-19019 August 2021 Rulemaking: Proposed Rule: Advanced Reactor Physical Security, Email Exchange Between Nrc and NEI Draft Pages from NEI-20-05 Rev. E ML21250A3782021-08-0202 August 2021 NEI 21-07, Revision 0, Technology Inclusive Guidance for Non-Light Water Reactors SAR Content for Applicants Using the NEI 18-04 Methodology ML21130A5972021-05-31031 May 2021 NEI 20-07, Guidance for Addressing Software Common Cause Failure in High Safety-Significant Safety Related Digital I&C Systems - Draft C ML21130A5962021-05-31031 May 2021 NEI, Guidance for Addressing Software Common Cause Failure in High Safety-Significant Safety Related Digital I&C Systems - Draft C ML21125A2842021-05-0505 May 2021 Transmittal of NEI 20-09: Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-Light Water Reactor Standard ML21110A0662021-04-20020 April 2021 Nei'S Comparison Table Between NEI 20-07 Sdos and NRC RGs and Endorsed IEEE Stds R2 ML21085A5552021-03-25025 March 2021 NEI 20-09 -Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-LWR PRA Standard, March 2021 ML21049A0572021-03-0202 March 2021 Rulemaking: Proposed Rule: NRC Markup of NEI-20-05 Draft B Comments on Methodological Approach and Considerations for a Technical Analysis to Demonstrate Compliance with the Performance Criteria of 10 CFR 73.55(a)(7) ML20339A4852020-11-23023 November 2020 NEI 20-09 - NRC Comments Resolved November 2020 ML20322A3392020-11-17017 November 2020 NEI ROP White Paper Modification of the Description of Unplanned Scrams with Complications for Nov 18 2020 ROP Public Meeting ML20245E5612020-08-31031 August 2020 Guidance for Addressing Software Common Cause Failure in High Safety-Significant Safety Related Digital I&C Systems ML20245E1472020-08-31031 August 2020 Attachment 1 - NEI Guidelines for the Implementation of the Risk-Informed Process for Evaluations Integrated Decision-Making Panel ML21050A0902020-08-31031 August 2020 Staff Detailed Comments - NEI 20_07 Draft Revision B -February 2021 ML20302A1152020-08-24024 August 2020 NEI 20-09 - Nlwr PRA Peer Review Rev1 August 2020 ML20211L7142020-07-24024 July 2020 Industry Position Regarding Safety Margin: Dispositioning Degraded or Failed Management Measures Above and Beyond Regulatory Requirements, and Meeting Performance Criteria; Follow Up to May 6, 2020 Letter on Smarter Program Inspection Prior ML20155K6852020-06-0101 June 2020 Availability of NEI 20-09, Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-LWR Standard, for NRC Review and Endorsement ML20154K5662020-06-0101 June 2020 Availability of NEI 20-09, Performance of PRA Peer Reviews Using the Asme/Ans Advanced Non-LWR Standard, for NRC Review and Endorsement ML20129J8592020-05-31031 May 2020 NEI 96-07, Appendix D Revision 1, Draft M, May 2020 ML20129J8582020-05-30030 May 2020 NEI 96-07, Appendix D, Revision 1, Draft M, May 2020 with Redline Strike ML20139A1902020-05-14014 May 2020 05-14-20 Changes to NEI 10-04 and NEI 13-10 Guidance for Identifying and Protecting Digital Assets Associated with Safety-Related and Important-to-Safety Functions ML20135H1682020-05-13013 May 2020 Request for NRC Endorsement of NEI 96-07, Appendix D, Rev 1 ML20134J0332020-05-13013 May 2020 Submittal of Response to Request for Additional Information (RAI) for NEI 14-05A, Revision 1, Guidelines for the Use of Accreditation in Lieu of Commercial Grade Surveys for Procurement of Laboratory Calibration and Test Services ML20126G3742020-04-30030 April 2020 NEI 96-07, Appendix D, Revision 1, Draft F, April 2020 with Redline Strike ML20126G3752020-04-30030 April 2020 NEI 96-07, Appendix D, Revision 1, Draft F, April 2020 ML20115E4132020-04-24024 April 2020 Endorsement of NEI White Paper, Changes to NEI 10-04 and NEI 13-10 Guidance for Identifying and Protecting Digital Assets Associated with the Balance of Plant, Dated April 2020 ML20114E1952020-04-22022 April 2020 NEI 96-07 Appendix D Revision 1, Draft B, April 2020 with Red-line Strike ML20107D8942020-04-13013 April 2020 Email from D. Young Draft B of NEI 20-05, Methodological Approach and Considerations for a Security Assessment to Demonstrate Compliance with the Performance Criteria of 10 CFR 73.55(TBD) ML20104A3072020-04-10010 April 2020 Draft NEI 20-05, Methodological Approach and Considerations for a Security Assessment to Demonstrate Compliance with the Performance Criteria of 10 CFR 73.55(TBD) ML20092J9202020-04-0101 April 2020 NEI 96-07 Appendix D Rev 1 February 2020 ML20092J9162020-04-0101 April 2020 NEI 96-07 Appendix D Rev 1 February 2020_Red Line 2023-06-06
[Table view] |
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Reactor Oversight Process Whitepaper -
Modification of the Description of Unplanned Scrams with Complications Performance Indicator to Reflect AP1000 Design Introduction For several years, the NRC staff and industry have been discussing potential changes to the Reactor Oversight Process (ROP) that would be needed to address new reactor designs. The new reactor design that is expected to enter into operation in the near future and then be subject to the ROP is the AP1000, two units of which are under construction at Southern Nuclears Vogtle site.1 The AP1000 incorporates passive safety features and other design and terminology differences from the plants in use when the ROP was conceived.2 Through several policy papers the staff exchanged with the Commission in the past seven years,3 the NRC aligned on the extent of changes needed in the ROP performance indicators described in NEI 99-02.4 In the most recent of those policy papers5, the staff stated its intent to engage with industry to discuss changes to the guidance for one performance indicator in particular, the Unplanned Scrams with Complications (USwC) performance indicator (also designated IE04 in NEI 99-02). This whitepaper describes the changes in NEI 99-02 needed to add AP1000-specific features and terminology to the guidance for the USwC performance indicator. With the submittal of this whitepaper, the ROP Task Force thus seeks to begin the engagement with NRC the staff mentioned in SECY-18-0091.
Discussion Under the ROP, the USwC performance indicator monitors the subset of unplanned automatic and manual scrams that either require additional operator actions beyond that of a normal scram or involve the unavailability of or inability to recover main feedwater during the scram response. Such events or conditions have the potential to present additional challenges to plant operators and therefore, may be more risk-significant than a normal, uncomplicated scram.
The criteria for determining whether a scram is complicated are presented in NEI 99-02, Figure 2, as six questions. (A copy of Figure 2 is attached to this whitepaper for the readers convenience.) A yes response to any of the six questions results in classifying the scram as complicated. One set of six questions applies to pressurized water reactors (PWRs); a different set of six questions applies to boiling water reactors (BWRs). With the coming entry of the AP1000 technology into the operating fleet, the PWR questions in Figure 2 need adjustment to reflect fundamental differences in design and terminology of the AP1000:
- 1. Was power lost to any Emergency Safeguards Features (ESF) 6 bus?
- 2. Was a safety injection signal received?
1 Overview available at https://www.southerncompany.com/innovation/nuclear-energy/plant-vogtle-3-and-4.html and https://www.georgiapower.com/company/plant-vogtle.html [retrieved August 18, 2020]
2 An overview of the AP1000 pressurized water reactor is provided at the following URL: https://www.westinghousenuclear.com/new-plants/ap1000-pwr 3
See, for example: SECY-13-0137, Recommendations for Risk-Informing the Reactor Oversight Process for New Reactors, December 17, 2013, ADAMS ML13263A339, and its associated SRM-SECY-13-0137, dated June 30, 2014; and SECY-18-0091, Recommendations for Modifying the Reactor Oversight Process for New Large Light Water Reactors with Passive Safety Systems such as the AP1000 (Generation Ill+ Reactor Designs), September 12, 2018, ADAMS ML17166A238..
4 NEI 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 7 (line-in/line-out version), August 31, 2013, ADAMS ML13261A116.
5 SECY-18-0091, page 5.
6 The acronym ESF is used in the current version of NEI 99-02 as an abbreviation of the term Emergency Safeguards Features and the term Engineered Safety Features. The next revision of NEI 99-02 will use the acronym ESF to mean Engineered Safety Features throughout.
Page 1 of 4 Revised November 17, 2020
Reactor Oversight Process Whitepaper -
Modification of the Description of Unplanned Scrams with Complications Performance Indicator to Reflect AP1000 Design Engineered Safety Features and the AP1000 Engineered Safety Features mitigate the consequences of accidents by maintaining the integrity of the fuel cladding, reactor coolant pressure boundary, and primary reactor containment. The AP1000 is designed so that only the Class 1E DC and Uninterruptible Power System (IDS) is required in order to initiate and actuate the systems necessary for maintaining core cooling and containment integrity. The AP1000 ESF systems (Containment, Passive Containment Cooling System, Containment Isolation System, Passive Core Cooling System) use the Class 1E DC and UPS System to provide power for mitigation and control of accident conditions, including a total loss of offsite or onsite AC power. The IDS provides reliable power for the safety-related equipment required for the plant instrumentation, control, monitoring, and other vital functions needed for shutdown of the plant. Loss of power to an IDS bus would result in a safeguards actuation signal and require additional operator actions beyond that of the normal scram.
Application to Scram Screening Questions in NEI 99-02
- 1. Given the above, the current screening question about losing any ESF bus (NEI 99-02, Rev. 7, page 21, line 15) should be modified to add a remark indicating this question does not apply to the AP1000:
- Was power lost to any ESF bus (For PWRs other than AP1000)?
- 2. The accompanying discussion of the question in NEI 99-02 (page 21, lines 17-33) should be copied, modified as shown below, and inserted below line 34 with a note indicating it applies only to AP1000 units:
- Was power lost to any battery backed Class 1E DC and UPS System (IDS) bus (For AP1000 only)?
During a reactor trip or during the period operators are responding to a reactor trip using reactor trip response procedures, was power lost to any battery backed IDS (Class 1E DC and UPS System) bus (e.g., IDSA-DD-1, IDSA-EA-1, IDSC-EA-3)? Operator action to re-energize the ESF bus from the main control board is allowed as an acceptable action to satisfy this metric.
The question is looking for a loss of power at any time for any duration where the bus was not energized/reenergized within 10 minutes. The bus must have:
Remained energized until the Reactor Trip response procedure was exited, or Been re-energized automatically (e.g., a standby diesel generator automatically restores IDSA-EA-1 when its inverter is manually bypassed to the Voltage Regulating Transformer), or Been re-energized from normal or emergency sources by an operator closing a breaker from the Main Control Room.
The question applies to all battery-backed IDS DC and 24- and 72-hour emergency AC busses. This does NOT apply to non-battery-backed IDS busses (e.g., IDSA-EA-2). It is Page 2 of 4 Revised November 17, 2020
Reactor Oversight Process Whitepaper -
Modification of the Description of Unplanned Scrams with Complications Performance Indicator to Reflect AP1000 Design expected that operator action to re-energize a battery backed IDS bus would not take longer than 10 minutes.
- 3. The current question about receiving a safety injection signal (NEI 99-02, Rev. 7, page 21, line
- 35) should be modified to add a note indicating this question does not apply to the AP1000:
- Was a Safety Injection signal received (For PWRs other than AP1000)?
- 4. The accompanying discussion of the question in NEI 99-02 (page 21, lines 35-43 and page 22, lines 1-2) should be copied, modified as shown below, and inserted below line 2 on page 22 with a note indicating it applies only to AP1000 units:
- Was a Safeguards Actuation signal received (For AP1000 only)?7 Was a Safeguards Actuation signal generated either manually or automatically during the reactor trip response? The questions purpose is to determine if the operator had to respond to an abnormal condition that required passive safety injection or respond to the actuation of additional equipment that would not normally actuate on an uncomplicated scram. This question would include any condition that challenged Reactor Coolant System (RCS) inventory, pressure, or temperature severely enough to require passive safety injection.
- 5. Conforming changes are needed in the depiction of PWR scram screening questions in Figure 2, as follows:
a) For the third decision diamond, which reads, Was power lost to any ESF bus?, add the following footnote: For AP1000: Was power lost to any battery backed Class 1E DC and UPS System (IDS) bus?
b) For the fourth decision diamond, which reads Was a Safety Injection signal received?, add the following footnote: For AP1000: Was a Safeguards Actuation signal received?
7 An additional footnote would be added to this question in NEI 99-02 to explain that for the AP1000, a safeguards actuation signal is used in the initiation logic of engineered safety features.
Page 3 of 4 Revised November 17, 2020
Reactor Oversight Process Whitepaper -
Modification of the Description of Unplanned Scrams with Complications Performance Indicator to Reflect AP1000 Design 1
2 3
4 5
6 8
See footnote 8
The boxed numbers to the left of each decision diamond do not appear in the original Figure 2. They were added here for ease of reference to the individual questions.
Page 4 of 4 Revised November 17, 2020