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CAC:MF6609, SFDP Clarifications (Approved, Closed) |
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MONTHYEARCNL-15-052, Annual Insurance Status Report2015-04-0101 April 2015 Annual Insurance Status Report Project stage: Request CNL-15-051, Guarantee of Payment of Deferred Premiums - 2014 Annual Report2015-04-0707 April 2015 Guarantee of Payment of Deferred Premiums - 2014 Annual Report Project stage: Request CNL-15-121, Shutdown Technical Specifications for Component Cooling System and Essential Raw Cooling Water System to Support Dual Unit Operation2015-06-17017 June 2015 Shutdown Technical Specifications for Component Cooling System and Essential Raw Cooling Water System to Support Dual Unit Operation Project stage: Request CNL-15-130, Distributed Control System (DCS) Data Storm Test Plan2015-07-10010 July 2015 Distributed Control System (DCS) Data Storm Test Plan Project stage: Request CNL-15-168, Notification of Construction Substantially Complete and Request for Operating License2015-08-12012 August 2015 Notification of Construction Substantially Complete and Request for Operating License Project stage: Request CNL-15-149, Application to Update Watts Bar Nuclear Plant Unit 1 License Condition 2.F to Allow Two-Unit Operation and Add License Condition 2.I (WBN-TS-15-01)2015-08-13013 August 2015 Application to Update Watts Bar Nuclear Plant Unit 1 License Condition 2.F to Allow Two-Unit Operation and Add License Condition 2.I (WBN-TS-15-01) Project stage: Request CNL-15-165, Submittal of Electromagnetic Interference (EMI) Survey Results2015-08-20020 August 2015 Submittal of Electromagnetic Interference (EMI) Survey Results Project stage: Request CNL-15-176, Financial Protection Requirements and Indemnity Agreements, Insurance Status2015-08-26026 August 2015 Financial Protection Requirements and Indemnity Agreements, Insurance Status Project stage: Request CNL-15-185, Supplement to Application to Update to License Condition 2.F to Allow Two-Unit Operation and Add License Condition (WBN-TS-15-01)2015-08-27027 August 2015 Supplement to Application to Update to License Condition 2.F to Allow Two-Unit Operation and Add License Condition (WBN-TS-15-01) Project stage: Request CNL-15-170, Responses to NRC Audit Review Questions for Essential Raw Cooling Water and Component Cooling Water System License Amendment Request2015-08-28028 August 2015 Responses to NRC Audit Review Questions for Essential Raw Cooling Water and Component Cooling Water System License Amendment Request Project stage: Request CNL-15-202, Financial Protection Requirements and Indemnity Agreements - Insurance Status Supplement2015-09-24024 September 2015 Financial Protection Requirements and Indemnity Agreements - Insurance Status Supplement Project stage: Request CNL-15-211, Financial Protection Requirements and Indemnity Agreements - Insurance Status Second Supplement2015-09-29029 September 2015 Financial Protection Requirements and Indemnity Agreements - Insurance Status Second Supplement Project stage: Request CNL-15-208, Technical and Regulatory Basis for Technical Specification 3.2.1, Heat Flux Hot Channel Factor (Fq (Z)), Revision 02015-09-30030 September 2015 Technical and Regulatory Basis for Technical Specification 3.2.1, Heat Flux Hot Channel Factor (Fq (Z)), Revision 0 Project stage: Request CNL-15-206, Response to Follow-Up Question Regarding Submittal of Electromagnetic Interference (EMI) Survey Results2015-10-0808 October 2015 Response to Follow-Up Question Regarding Submittal of Electromagnetic Interference (EMI) Survey Results Project stage: Request CNL-15-193, Distributed Control System (DCS) Data Storm Test Results2015-10-0909 October 2015 Distributed Control System (DCS) Data Storm Test Results Project stage: Request ML15282A0512015-10-31031 October 2015 NUREG-0847, Supp. 29, Safety Evaluation Report Related to the Operation of Watts Bar Nuclear Plant, Unit 2, Docket No. 50-391, Tennessee Valley Authority. Project stage: Request ML15344A3182015-12-23023 December 2015 Issuance of Amendment Regarding Fire Protection License Conditions Project stage: Approval 2015-08-12
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Category:Letter type:CNL
MONTHYEARCNL-24-017, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions2024-01-17017 January 2024 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions CNL-24-016, Supplement to Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14)2024-01-10010 January 2024 Supplement to Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14) CNL-23-052, Application to Adopt TSTF-427-A, Revision 2, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability2024-01-0909 January 2024 Application to Adopt TSTF-427-A, Revision 2, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability CNL-23-062, Application to Revise the Technical Specifications Section 3.8.2, AC Sources-Shutdown, to Remove Reference to the C-S Diesel Generator (WBN-TS-23-018)2024-01-0808 January 2024 Application to Revise the Technical Specifications Section 3.8.2, AC Sources-Shutdown, to Remove Reference to the C-S Diesel Generator (WBN-TS-23-018) CNL-23-069, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-12-21021 December 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation CNL-23-036, Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08)2023-12-18018 December 2023 Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08) CNL-23-001, Rebaseline of Sections 3.1 and 3.2 of the Technical Specifications (WBN-TS-23-01)2023-12-13013 December 2023 Rebaseline of Sections 3.1 and 3.2 of the Technical Specifications (WBN-TS-23-01) CNL-23-067, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-11-27027 November 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-059, Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-2023-09-20020 September 2023 Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 CNL-23-061, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-09-20020 September 2023 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision CNL-23-057, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 642023-09-0505 September 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 64 CNL-23-045, License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Bolts (WBN-TS-23-010)2023-08-0707 August 2023 License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Bolts (WBN-TS-23-010) CNL-23-028, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06)2023-08-0202 August 2023 Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06) CNL-23-055, Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills2023-07-25025 July 2023 Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills CNL-23-053, Tennessee Valley Authority - Radiological Emergency Plan Revisions2023-07-18018 July 2023 Tennessee Valley Authority - Radiological Emergency Plan Revisions CNL-23-020, Application to Revise Technical Specifications to Adopt TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control (WBN-TS-22-06)2023-06-28028 June 2023 Application to Revise Technical Specifications to Adopt TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control (WBN-TS-22-06) CNL-23-049, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan .2023-06-26026 June 2023 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan . CNL-23-044, Transmittal of Revision 3 to WCAP-18774-P and WCAP-18774-NP, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173 P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out2023-06-0101 June 2023 Transmittal of Revision 3 to WCAP-18774-P and WCAP-18774-NP, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173 P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out CNL-23-042, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-05-16016 May 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-043, Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09)2023-05-0404 May 2023 Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09) CNL-23-030, Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update2023-04-27027 April 2023 Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-23-032, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 412023-04-27027 April 2023 Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 41 CNL-23-033, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-04-24024 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision CNL-23-029, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-04-11011 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-023, Annual Insurance Status Report2023-03-30030 March 2023 Annual Insurance Status Report CNL-23-022, Decommissioning Funding Status Report2023-03-29029 March 2023 Decommissioning Funding Status Report CNL-23-024, TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report2023-03-29029 March 2023 TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report CNL-23-002, Application to Revise Watts Bar Nuclear Plant Units 1 and 2 Technical Specifications to Change the Number of Tritium Producing Burnable Absorber Rods (WBN-TS-21-02) and Proposed Revision to Reactor Vessel Surveillance Capsule Removal Sche2023-03-20020 March 2023 Application to Revise Watts Bar Nuclear Plant Units 1 and 2 Technical Specifications to Change the Number of Tritium Producing Burnable Absorber Rods (WBN-TS-21-02) and Proposed Revision to Reactor Vessel Surveillance Capsule Removal Schedu CNL-23-021, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-03-0808 March 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-23-015, Expedited Application to Modify the Watts Bar Nuclear Plant, Unit 1 and Unit 2 Technical Specifications for Main Control Room Chiller Completion Time Extension (WBN-TS-22-08)2023-02-27027 February 2023 Expedited Application to Modify the Watts Bar Nuclear Plant, Unit 1 and Unit 2 Technical Specifications for Main Control Room Chiller Completion Time Extension (WBN-TS-22-08) CNL-23-003, Browns Nuclear Plant, Units 1, 2 & 3; Sequoyah Nuclear Plant, Units 1 & 2; and Watts Bar Nuclear Plant, Units 1 & 2 - Organizational Topic Report TVA-NPOD89-A2023-01-30030 January 2023 Browns Nuclear Plant, Units 1, 2 & 3; Sequoyah Nuclear Plant, Units 1 & 2; and Watts Bar Nuclear Plant, Units 1 & 2 - Organizational Topic Report TVA-NPOD89-A CNL-23-009, Response to Request for Additional Information Request to Revise Technical Specification 3.4.122023-01-0404 January 2023 Response to Request for Additional Information Request to Revise Technical Specification 3.4.12 CNL-23-008, Tennessee Valley Authority Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2022-12-22022 December 2022 Tennessee Valley Authority Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-22-109, Steam Generator Tube Inspection Report to Reflect TSTF-577 Reporting Requirements2022-12-22022 December 2022 Steam Generator Tube Inspection Report to Reflect TSTF-577 Reporting Requirements CNL-22-101, American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI, Request for Alternative WBN-2-ISI-012022-11-28028 November 2022 American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI, Request for Alternative WBN-2-ISI-01 CNL-22-106, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision. Includes CECC EPIP-14, Revision 38, Nuclear Emergency Public Information Organization and Operat2022-11-28028 November 2022 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision. Includes CECC EPIP-14, Revision 38, Nuclear Emergency Public Information Organization and Operatio CNL-22-099, Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update2022-10-31031 October 2022 Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-22-098, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC EPIP-7, Rev. 45 & CECC EPIP-8, Rev. 552022-10-17017 October 2022 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC EPIP-7, Rev. 45 & CECC EPIP-8, Rev. 55 CNL-22-085, Response to Request for Additional Information Regarding Sequoyah Nuclear Plant (Sqn), Units 1 and 2 and Watts Bar Nuclear Plant (Wbn), Units 1 and 2, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Al2022-09-0202 September 2022 Response to Request for Additional Information Regarding Sequoyah Nuclear Plant (Sqn), Units 1 and 2 and Watts Bar Nuclear Plant (Wbn), Units 1 and 2, American Society of Mechanical Engineers Operation and Maintenance Code, Request for Alte CNL-22-077, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2022-08-11011 August 2022 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-22-030, Application to Revise Technical Specification 3.4.12, Low Temperature Overpressure Protection System for Sequoyah Nuclear Plant (SQN-TSC-22-01) and TS 3.4.12 Cold Overpressure Mitigation System for Watts Bar Nuclear Plant (WBN-TS-22-03)2022-07-27027 July 2022 Application to Revise Technical Specification 3.4.12, Low Temperature Overpressure Protection System for Sequoyah Nuclear Plant (SQN-TSC-22-01) and TS 3.4.12 Cold Overpressure Mitigation System for Watts Bar Nuclear Plant (WBN-TS-22-03) CNL-22-039, Application to Revise Technical Specifications to Adopt TSTF-554-A, Revision 1, Revise Reactor Coolant Leakage Requirements (BFN TS-537) (SQN-21-05) (WBN-TS-21-04)2022-07-13013 July 2022 Application to Revise Technical Specifications to Adopt TSTF-554-A, Revision 1, Revise Reactor Coolant Leakage Requirements (BFN TS-537) (SQN-21-05) (WBN-TS-21-04) CNL-22-071, Supplement to Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections (SQN-TS-21-03 and WBN-TS-21-08)2022-07-13013 July 2022 Supplement to Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections (SQN-TS-21-03 and WBN-TS-21-08) CNL-22-070, Status Regarding the Improved Flood Mitigation System Project2022-06-30030 June 2022 Status Regarding the Improved Flood Mitigation System Project CNL-22-008, and Watts Bar Nuclear Plant - Application to Revise Technical Specifications to Adopt TSTF-529, Clarify Use and Application Rules (BFN-TS-541, SQN-TS-21-09, and WBN-TS-22-002)2022-06-13013 June 2022 and Watts Bar Nuclear Plant - Application to Revise Technical Specifications to Adopt TSTF-529, Clarify Use and Application Rules (BFN-TS-541, SQN-TS-21-09, and WBN-TS-22-002) CNL-22-064, Response to Request for Additional Information Regarding Tennessee Valley Authority License Amendment Request to Revise Emergency Plan Implementing Procedure Regarding Seismic Event Emergency Action Level Change2022-06-0909 June 2022 Response to Request for Additional Information Regarding Tennessee Valley Authority License Amendment Request to Revise Emergency Plan Implementing Procedure Regarding Seismic Event Emergency Action Level Change CNL-22-068, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2022-06-0808 June 2022 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions CNL-22-047, Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions2022-05-23023 May 2022 Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions CNL-22-043, Response to Request for Additional Information and Confirmation of Information Regarding Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board.2022-05-0202 May 2022 Response to Request for Additional Information and Confirmation of Information Regarding Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board. CNL-22-046, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan.2022-04-28028 April 2022 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan. 2024-01-09
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Text
Tennessee Valley Authority, 1101 Market Street, Chattanooga , Tennessee 37 402 CNL-15-130 July 10, 2015 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington , D.C. 20555-001 Watts Bar Nuclear Plant, Unit 2 Construction Permit No. CPPR-92 NRC Docket No. 50-391
Subject:
WATTS BAR NUCLEAR PLANT (WBN) UNIT 2 - DISTRIBUTED CONTROL SYSTEM (DCS) DATA STORM TEST PLAN
Reference:
NUREG-0847 , Supplement No. 23, "Safety Evaluation Report Related to the Operation of Watts Bar Nuclear Plant, Unit 2," dated July 2011 (ML11206A499)
The purpose of this letter is to provide the Distributed Control System (DCS) Data Storm Test Plan which satisfies a verbal request from the Nuclear Regulatory Commission (NRC) staff.
The completion of the Data Storm Test is the subject of Supplemental Safety Evaluation Report (SSER) 23, Appendix HH , Open Item No. 83 contained in the above reference . TVA will provide the results of the data storm test after completion of the test which is currently scheduled for August 5, 2015. provides the DCS Data Storm Test Plan . Enclosure 2 provides the commitment to provide the test results to the NRC .
Should you have questions regarding this submittal, please contact Gordon Arent at (423) 365-2004.
ctfully, u~
J ~~Shea icJ President, Nuclear Licensing Enclosures cc: See Page 2
U.S. Nuclear Regulatory Commission CNL-15-130 Page 2 July 10, 2015
Enclosures:
- 1. Watts Bar Nuclear Plant, Unit 2, Distributed Control System (DCS) Data Storm Test Plan
- 2. List of Commitments cc (Enclosures):
U.S. Nuclear Regulatory Commission, Region II NRC Project Manager - Watts Bar Nuclear Plant, Unit 2 NRC Senior Resident Inspector - Watts Bar Nuclear Plant, Unit 2
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNIT 2 DISTRIBUTED CONTROL SYSTEM (DCS) DATA STORM TEST PLAN PURPOSE:
The purpose of this test plan is to establish the requirements, test methodology, and acceptance criteria for the non-safety related Foxboro (Invensys) Intelligent Automation (I/A) Distributed Control System (DCS) Data Storm test. This test plan is driven by Supplemental Safety Evaluation Report (SSER) 23 of NUREG-0847 (ADAMS Accession No. ML1206A499), where Tennessee Valley Authority (TVA) was to provide the results of the DCS data storm test to the Nuclear Regulatory Commission (NRC).
DCS CONFIGURATION:
The Watts Bar Nuclear Plant (WBN) Unit 2 DCS is the control and monitoring platform for most of the Nuclear Steam Supply System (NSSS) and Balance of Plant (BOP) systems. The basic configuration of the DCS are redundant fault tolerant control processor (CP) pairs, redundant power supplies with diverse power sources, redundant communication networks, and redundant operator workstations. Redundant field-bus modules (FBM) are utilized for critical inputs and outputs. The system is designed such that the control system is not affected by the failure of a single device or component for functions important to safe plant operation. The DCS has been segmented, consisting of 15 functional groups, each with a redundant CP pair. See Table 1 below. This segmentation ensures that a failure of one CP pair, with all outputs failing high, low, or as is, maintains independence between redundant control functions and limits the effects of failures on the critical control system.
TABLE 1: FUNCTIONAL GROUPS GROUP PRIMARY FUNCTION (CP PAIR) 01 Steam Generator (SG) 1 Level, Feedwater (FW) Flow 02 SG 2 Level, FW Flow 03 SG 3 Level, FW Flow 04 SG 4 Level, FW Flow Main Feedwater (MFW) Pump Speed Control & Steam Dump Loss of Load 05 Interlock 06 Rod Control 07 SG 1 Power Operated Relief Valve (PORV) (Atmospheric Dump) 08 SG 2 PORV (Atmospheric Dump) 09 SG 3 PORV (Atmospheric Dump) 10 SG 4 PORV (Atmospheric Dump) 11 Condenser Steam Dump Pressurizer (PZR) A [Pressure, Level, Charging, Letdown, Spray, Cold 12 Overpressure Mitigation System (COMS)]
13 PZR B (Pressure, Level, Charging, Letdown, Spray, COMS) 14 Auxiliary Control System A 15 Auxiliary Control System B E1-1
DCS NETWORK CONFIGURATION:
The WBN Unit 2 DCS is configured with two communication links to the Integrated Computer System (ICS) using separate Network Interface Controller (NIC) hardware and subnet address from the DCS mesh network. The DCS mesh network achieves redundancy using two dedicated NIC cards in each Operator and Engineering workstation. Additionally, DCS is configured with redundant networks and hardwired analog control signal transmission between CP pairs, so that no critical control functions are totally dependent upon the network to ensure the system will continue to function if the network fails.
- DCS Network Impacts to Multiple/Common Systems:
o There are no digital communications from DCS to any other control system or protection system. The analog inputs from the protection system are transmitted via qualified isolators as on WBN Unit 1.
o Firewalls between the DCS and ICS limit the volume of data traffic and ensure that common cause events, such as a data storm, do not prevent DCS from performing its design function or prevent any other system from performing its design function.
- This configuration ensures DCS network failures will not propagate to other control or protective systems and result in a condition more severe than already described in Chapter 15 of the Final Safety Analysis Report.
Some communication signals are used in more than one functional group or processor pair and are transmitted to other processors by either hardwired analog connection, peer-to-peer network connection or both. No critical control function is dependent upon the network alone. Figures 1 and 2 provide a depiction of the network configuration. Table 2 below provides the switch and port configuration.
TABLE 2: DCS SWITCH AND PORT CONFIGURATION Network Switch Port Control Groups 1 SG 1 Level, FW Flow 2 SG 2 Level, FW Flow 3 SG 3 Level, FW Flow 4 SG 4 Level, FW Flow 5 MFW Pump Speed Control, Main Feed Pump (MFP)
W2SW01/W2SW02 Recirculation Control, SG Blowdown Control, Cold Leg Accumulator (CLA) N2 Vent Header Control, Residual Heat Removal (RHR) Heat Exchanger (Htx) A Flow Control, Charging Header Reactor Coolant Pump (RCP) Seals 6 Rod Control 7 Hotwell Level Control, SG 1 PORV E1-2
TABLE 2: DCS SWITCH AND PORT CONFIGURATION (Continued)
Network Switch Port Control Groups 8 RHR Htx B Flow Control, SG 2 PORV, Main Feed Pump Turbine (MFPT) Oil Htx A Temp, MFPT Oil Htx B Temp, #3 Heater Drain Tank Level/Flow, #3 Heater Drain Tank Level Bypass 9 Hotwell Pump Discharge Header Flow, SG 3 PORV, #7 Heater Drain Tank Level, #7 Heater Drain Tank Level Bypass, Stator Cold Leg H2O Temperature, H2 Side Seal Oil Temperature, Air Side Seal Oil Temperature, Raw Cooling Water (RCW) Exciter Htx Temperature, RCW H2 Htx Temperature, Main Turbine Oil Tank Temp W2SW01/W2SW02 (continued) 10 SG 4 PORV, RHR Htx Bypass Flow 11 Condenser Steam Dump Pressure Control, Loss of Load Interlock 12 Primary Water Flow, Primary Water Batch, Boric Acid Flow, Boric Acid Batch, PZR Pressure, PZR Pressure Loop (LP) 1 Spray, Excess Letdown Flow 13 Boric Acid Tank B Recirculation, Charging Flow, Letdown Pressure, Letdown Htx Outlet Temp, PZR Pressure LP 2 Spray, PZR Level, RHR Letdown, Volume Control Tank (VCT) Level 1 Auxiliary Control Room (ACR) VCT Level, ACR SG 1 PORV, ACR SG 3 PORV, ACR Excess Letdown Flow, ACR RHR Letdown, ACR Charging Header Flow, ACR RHR Htx A, ACR W2SW03/W2SW04 RHR Htx Bypass 2 ACR Letdown Htx Temp, ACR Letdown Pressure, ACR SG 2 PORV, ACR SG 4 PORV, ACR RHR Htx B, ACR Charging Flow, ACR CLA N2 Vent REQUIREMENTS:
TVAs Engineering Standard Specification SS-E18.15.01, Requirements for Digital Systems (Real-Time Data Acquisition and Control Computer Systems), provides guidelines on testing digital systems and confirming robustness of critical design features including Data Storm testing. It is preferred that data transfer and communication routines be robust with designed in fault recovery such that loss of communications or communications overloads do not adversely affect critical design features. Although the DCS is not safety related, it provides critical plant control and monitoring functions and therefore a Data Storm (network system is overwhelmed by continuous multicast or broadcast traffic) and a loss of network, which can be caused by a Data Storm, are credible failures and thus testing is needed to confirm the ability of the DCS to sustain critical design features.
E1-3
The WBN Unit 1 and Sequoyah Nuclear Plant (SQN) Unit 1 and Unit 2 have similar DCS platforms already installed and are operational. However, WBN Unit 2 impacts more systems.
Although WBN Unit 1 and SQN Unit 1 and 2 demonstrated during their Factory Acceptance Test that a data storm can disable the communication networks and cause one CP of a pair to become non-functional, the control groups, however, continue to operate. The WBN Unit 2 DCS has yet to confirm that the installed configuration will sustain a data storm event without experiencing a plant upset. Therefore, TVA has committed to perform a network data storm test on the installed system prior to final commissioning.
A network data storm test will be performed with the system installed and prior to final commissioning. The test will confirm that the system will continue to function with a failed communication network without any plant upset.
ANALYSIS:
In SSER 23, Section 7.7.1.4.4.2 states that TVA provided a description of the Foxboro I/A Mesh Network, including an analysis of credited network failures. Based on its review of the analysis, the NRC concluded that a Foxboro I/A Mesh Network failure in one segment will not disable another segment. The Data Storm test results are to be analyzed to ensure CP or CP pairs sustain their design function during the data storm event. Segmentation Analysis concluded that events listed in SSER 23, Section 7.7.1.4.4.1, items (1) through (8), will not be caused by the propagation of failures. This test will document that the CP or CP pairs sustain their design function through a data storm event and thereby validates the Segmentation Analysis.
TEST METHODOLOGY:
With the WBN Unit 2 DCS installed, a network Data Storm will be generated to validate system performance. System performance will be accessed thru monitoring and trending critical attributes of each control processor including control processor loading, processor overruns and system alarms. Additionally, Input thru Output timing metrics will be monitored using external test devices on sample Field Bus Module types. The input/output monitoring will demonstrate the effect of the data storm on the processing cycle time of 200 msec and 1 sec requirements which are detailed in the purchase specification. Network Storm testing will be implemented in two phases: Loss of Network and Data Storm. Loss of network is not addressed within this testing plan as it will be performed in a separate test. The loss of network test will confirm that upon loss of network, the systems logic detects loss of peer-to-peer points and the control algorithm switches to the hardwired analog backups.
The Data Storm is initiated in two phases (Broadcast and Multicast) for up to three separate locations within the DCS network, workstation connection, CP switch connections, and the Auxiliary Control Room network switch. Figure 1 provides a depiction of the data storm generation locations.
E1-4
- Broadcast Storm o Overwhelm the network with continuous traffic at maximum speed. This is accomplished utilizing a Packet Generator to send data (all 1s) at maximum speed onto the network with no specific address.
This test validates the network switch limiters.
- Multicast Storm o Overwhelm the network with continuous traffic at maximum speed. This is accomplished utilizing a Packet Generator to send data (all 1s) at maximum speed onto the network to a specific media access control (MAC) address.
This test forces the DCS to process the network data and demonstrates that CP pairs continue to function independent of the network.
ACCEPTANCE CRITERIA:
- Clause 6.3 of IEEE Standard 603-1991 is met and the propagation of failures does not take place beyond the Foxboro I/A mesh network from one segment to another. There is no effect on the Reactor Protection System.
- During a simulated data storm event, network limiter settings/functions are validated.
- During a simulated data/multicast storm, DCS sustains process control capability, and control system segmentation is maintained as detailed in SSER 23, Section 7.7.1.4.4.1, items (1) through (8) by monitoring demand signals.
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WBN UNIT 2 DCS DATA STORM TEST PLAN FIGURE 1: DCS NETWORK CONFIGURATION (INFO ONLY - SOME DETAILS AND CONNECTIONS ARE NOT SHOWN)
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WBN UNIT 2 DCS DATA STORM TEST PLAN FIGURE 2: SHARED NETWORK E1-7
ENCLOSURE 2 LIST OF COMMITMENTS
- 1. TVA will provide the results of the data storm test after completion of the test which is currently scheduled for August 5, 2015.
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