ML11138A283
| ML11138A283 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/19/2011 |
| From: | Steely J Duke Energy Carolinas |
| To: | Widmann M NRC/RGN-II/DRS/OLB |
| Lawrence Vick | |
| References | |
| Download: ML11138A283 (5) | |
Text
April 19, 2011 U.S Nuclear Regulatory Commission Mr. Malcolm T. Widmann, Chief Operator Licensing Branch, Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Re: OCONEE NUCLEAR STATION Second Simulator Testing Schedule Mr. Widmann, In Quarter 1 of 2010, Oconee Nuclear Site completed building and testing a second full scope simulator. The new simulator is referred to a Simulator Bravo (Sim-B) and the existing Simulator is referred to as Simulator Alpha (Sim-A). Sim-B is located at the Oconee Training Center adjacent to Sim-A. Sim-A and Sim-B are referenced to Oconee Unit 1.
This letter includes the following:
- Design
- Initial Tests
- Test Plan and Testing Credit Design The design scope for the Sim-B was to build a Sim-A functionally equivalent Unit 1 referenced simulator and control room environment. All modeling software will execute identically regardless of running in the Sim-A or Sim-B environment. This design bounded changes to hardware and interface Input/Output (I/O) levels and therefore excluded modeling changes.
Likewise bounding the required verification and validation (i.e. the modeling software configuration was not changed). Since the existing Sim-A modeling software design did not require updates to support the Sim-B hardware the existing Sim-A software modeling executes identically on both simulators Sim-A and on Sim-B.
During the design of Sim-B, effort was made to purchase Sim-A functionally identical or equivalent hardware that interfaces the identical Sim-A I/O layout, executive control, modeling, OAC, PMC, EHC, Moore Controller and Chessell Chart recorder design. Sim-B utilizes a functionally equivalent set of computers and hardware panels. Sim-B modeling is not subject to any functional input differences in panel response when connected to either Sim-A panel hardware or Sim-B panel hardware.
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The following table details the hardware and interface functional equivalences:
Component Equivalence Sim-A Sim-B IO (DO, DI, AO, AI) Difference TMI TMI 1UB1 1UB1 1UB2 1UB2 1AB1 1AB1 New RPS) 1AB3 2AB3 RTP 1VB1 1AB3 1VB2 2AB3 1VB3 1VB1 ECB 1VB2 Old RPS 1VB3 ECB Old RPS OAC Same PMC Same EHC Same Strings Same Moore Controller Same Chessell Recorders Same Network Difference 10.10.10.xxx 10.10.30.xxx Sim-A I/O is a hybrid design that includes RTP I/O and TMI I/O. Sim-A panels (1UB1, 1UB2, 1AB1) that makeup the horseshoe, were upgraded to TMI I/O in December 2010 and the new RPS cabinetry was delivered with TMI I/O. The remaining Sim-A panels (1AB3, 2AB3, 1VB1, 1VB2, 1VB3, ECB) are planned for upgrade at a future date.
Sim-B I/O interface hardware is a monolithic design that includes only TMI I/O. For both simulators, the I/O buffer layout is identical resulting in functional equivalence.
Initial Tests ANSI/ANS 3.5-1998 Section 4.4.1, Verification Testing, states that the extent and nature of the testing to be performed shall be based on the design of the software and its affect on simulator fidelity. As previously noted, Sim-B design difference is bounded to the hardware and I/O system. Tests were conducted to that extent. Sim-B tests verified component like-for-like compatibility with Sim-A ensuring Sim-B and Sim-A component level functional equivalence.
Each and every panel component was verified at least twice; initially at the vendors location and subsequently onsite in an integrated mode.
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ANSI/ANS 3.5-1998 Section 4.4.2, Validation Testing, requires a comparison of results and requires validation testing Section 4.4.2(3) whenever there are changes that affect simulator capability or repeatability. The baseline for the comparative result is Sim-A. The Sim-B design bounded the changes to hardware and to the I/O interface. The Sim-B tests results compared to Sim-A demonstrates the same result for the same action. This result was determined by comparing the expected change on Sim-B to the demonstrated result on Sim-A. The Digital Inputs and Digital Outputs were validated by completing a bit-for-bit comparison. Analog Inputs were validated by viewing the full range 0.0 to 1.0 value change for the Analog Input I/O location in question. Analog Outputs were similarly validated by updating the I/O location for that Analog Output and then viewing the expected component response. Since the I/O mapping alignments are identical, unmodified Sim-A modeling executes identically on Sim-B.
In addition to the hardware and I/O interface verification and validation tests, the following tests were completed:
- Scenario Based testing (SBT) Spot Checking
- Performance Tests:
o PT/N/01, Plant Startup to 100% from Cold Shutdown o PT/N/02, Plant Shutdown from 100% to Cold Shutdown.
o PT/N/03, Steady State Comparison Test
- Transient Tests:
o PT/T/01: Anticipatory reactor trip on loss of main feedwater (Unit 1; September 12, 2001) o PT/T/02: Loss of MFDW with EFW overfeed o PT/T/03: Loss of offsite power o PT/T/04: Trip of one RCP from 100% power (Unit 2; April 12, 2006) o PT/T/06: Reactor Trip with Turbine Bypass Valve Bias Failure (Unit 3; August 31, 2005) o PT/T/07: LBLOCA with loss of offsite power (LOOP) o PT/T/08: Double-ended Main Steam line break from full power o PT/T/09: Depressurization with pressurizer spray o PT/T/10B: SBLOCA with B&C HPIPs inoperable (Use venting) o PT/T/11B: SBLOCA without HPI - HPI eventually restored o PT/T/12: Loss of all feedwater resulting in HPI Forced Cooling o PT/T/13: TMI-2 Accident o PT/T/14A: Steam Generator tube rupture with no operator action o PT/T/14B: Steam Generator tube rupture with operator action o PT/T/15: Dropped control rod (Unit 3; August 16, 2006) o PT/T/16: ATWS/Loss of Main Feedwater transient The Performance Tests and Shutdown/Startup Tests results were reviewed by the Simulator Configuration Management Instructor SME.
The Transient Tests results were reviewed by the Simulator Configuration Management Instructor SME and compared to Sim-A Transient Test results.
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Based on the test results Sim-B hardware and I/O verification and validation, SBT spot checks, Performance Test and Transient Test results, Oconee has concluded that Sim-B simulator response is functionally equivalent to Sim-A.
Test Plan and Testing Credit Presently ANSI/ANS 3.5-1998 and 10CFR55.46, Simulation Facility requirements are specific to single simulator simulation facilities. Oconee presently has two Oconee Unit 1 referenced full-scope functionally equivalent simulators. Oconee requests the NRC consider for acceptance the following testing and test credit plan:
- Grandfather of the certified Sim-A malfunction testing credit to Sim-B Simulation models and initial conditions execute identically without regard to simulator environment Sim-A or Sim-B.
- Relative to changes that involve hardware/software:
Hardware - Verification and Validation on both simulators is conducted.
Software - Verification and Validation on a single simulator. Acceptance of test credit for both simulators.
- Single simulator SBT testing credit be accepted for both simulators
- Single simulator Annual Testing credit be accepted for both simulators based on the schedule below ANS 3.5-1998 Section 4.4 states that performance testing shall be conducted in an integrated manner. This requirement precludes taking performance testing credit for having performed tests on the other full-scope simulator.
Proposed annual testing schedule:
Testing Year Simulator 2011 Sim-B 2012 Sim-A 2013 Sim-B 2014 Sim-A 2015 Sim-B Physical hardware changes require verification and validation be conducted on both simulators.
In 2010, the required annual testing was completed on both simulators.
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Summary of Testing Completed on Sim-B
- Complete I/O testing o Digital Inputs o Digital Outputs o Analog Inputs o Analog Outputs
- OAC (Plant Computer)
- PMC (Radiation Monitoring)
- Strings
- Moore Controllers
- Chessell Chart Recorders
- SBT Spot Checking
- Performance Tests
- Transient Tests Please provide comments to JR Steely (864-873-3446) or Keith Welchel (864-873-3349).
Sincerely, John R. Steely Manager, Operator Training Oconee Nuclear Site Page 5