ML20043F639
| ML20043F639 | |
| Person / Time | |
|---|---|
| Issue date: | 02/12/2020 |
| From: | Office of the Chief Human Capital Officer, Woodard Corp |
| To: | |
| Gary Callaway | |
| Shared Package | |
| ML20043F634 | List:
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| References | |
| Download: ML20043F639 (40) | |
Text
Chapter 11 QUALIFICATION, SITE ACCEPTANCE, AND SURVEILLANCE TESTING
Learning Objectives This lesson will provide students an overview of:
- 2. Supplier's installation, set-up, and initial run
- 3. Licensee's pre-operational tests to verify EDG performance, establish baseline data
- 4. Ongoing surveillance testing by the licensee
- 5. "A typical surveillance run" (on grid)
EDG "Type Qualification" Tests for Nuclear Service All NPP EDGs type qualified RG 1.9 Rev 4, IEEE 387-1995 Clause 6 Prior qualification of similar design may reduce required testing, analysis Analysis used when testing is unneeded/impractical Testing by manufacturer, or independent third party (Requires 10 CFR 50 Appendix B Quality Assurance program)
For early plants, EDG qualification tests on-site (IEEE 387-1972 was not yet adopted)
Three Basic Type Qualification Tests Load Capability Tests:
Continuous rated load until engine temps stable Short-time rated load 2 hrs, continuous rated load 22 hrs (either order)
Load rejection test at short-time rating Engine speed increase: < 75% of between nominal (60Hz) RPM and over-speed trip set-point, also < 15% of nominal RPM.
Complete light/no-load test equal to the design light load, for allowed duration. Note: Follow with 50% load for 0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.
Three Basic Type Qualification Tests (continued)
Start and Load Acceptance Tests:
Start, reach specified voltage, frequency in required time Immediately accept single step load > 50% of continuous kilowatt (KW) rating At least 90 such tests with EDG initially at warm-standby At least 10 tests with engine at normal operating temps for the load ("hot start")
IF any failure: Design review, corrective action, more tests 100 consecutive starts without failure SM
Three Basic Type Qualification Tests (continued)
Margin Tests:
Extra high stress tests to confirm safety margin for plant's design.
Include loads = 110% of most severe single step load in profile.
Generator, exciter, voltage regulator Accept load without voltage collapse, or inability of voltage to recover.
Engine and governor Accept load without stalling, then recover to normal operating speed.
Note: Hz and V excursions may exceed limits specified for loads.
Additional EDG Evaluation (Test or Analysis)
Aging of Components, Assemblies:
IEEE 387-1995 Evaluation of aging for safety-related parts.
- Age-related failure mechanism potential must be evaluated.
- If significant, qualify by test (preferred)/analysis/both. Those parts with lifetime < EDG system life objective (40 years) must have maintenance/replacement interval defined.
Seismic Qualification Requirements IEEE 344-1987 seismic qualification required for safety-related components. Also, non-safety items require analysis/test, to show no impact on EDG during seismic event. STfT
Analysis/Test of EDG Design Changes IEEE 387 now requires analysis of design changes to previously qualified EDGs. Categorized as major or minor:
Major Changes Must be re-qualified, as if new design Minor Changes Qualify by analysis / testing / both The category given a (proposed) design change is influenced by function, use in other EDGs, experienced engineering judgment.
Examples?
"Factory" Production Testing Initial "break-in" run Load test engine, with dynamometer or generator. Log data per 5.2.1 of IEEE 387-1995. Do these in any order:
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> each at 50% and 75% of continuous rating 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> each at 100% and 110% of continuous rating Set and check engine-mounted alarms and shutdowns.
Perform post-test inspections. Document results.
Test generator to NEMA MG 1-1993
Initial On-Site Set-Up of EDG SM 11.3 Anchor EDG, align with gen, check web deflection Engine internal checks, inspections (clearances, etc.)
Governor, over-speed governor set-up Engine trip and alarm relay calibration Generator internal checks Generator output breaker Generator load sequencer Engine air start system
Initial On-Site Set-Up (continued)
Fuel oil analysis! Check fuel storage-transfer system.
(function, integrity, capacity, filters, gauges, alarms)
Lube oil analysis! Check lube oil system.
Coolant analysis! Check cooling system.
Verify engine room ventilation system function, including fan rotation and air flow (cfm)
EDG now ready for initial Site Acceptance Tests.
Site Acceptance Testing To confirm performance of installed system IEEE 387 Clause 7 and Table 3, Student Manual Figure 11-1 Starting Test: ("Fast Start") Rated frequency and voltage within limits, in time specified 35 Load Acceptance Test: Accept design basis load sequencing (V and Hz limits).
Rated Load Test: Carry continuous rating until engine temps stable (plus 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />), then short-time rating 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> (typ 110%).
Site Acceptance Testing (continued)
Electrical Tests:
Generator, exciter, voltage regulator, engine governor, etc.
Subsystem Tests:
Controls, protective features, instrumentation, data logging, etc.
Site Acceptance Tests complete EDG ready for initial use. $
NEXT: "Pre-Operational" tests Licensee required to demonstrate - document EDG performance.
Regulatory prerequisite to declaring the EDG system operational.
Pre-Operational Testing (SM Figure 11-1)
Pre-Operational tests confirm logic circuits, controls programming.
(Ref Generic Letter 96-01)
All starting modes demonstrated: Local manual, Control Room manual, LOOP, SIAS from RPS, combined SIAS + LOOP.
Steps should be taken to reduce engine wear during ALL testing, including keep-warm, pre-lube, cool-down at reduced power IEEE 387-1995, GL 84-15, GL 94-01 Reliability Test: Demonstrates ready for service. Minimum of 25 (slow) Start and Load-Run tests, without failure, on each EDG
Pre-Operational Testing (continued)
(Slow-) Start Test: Verifies design Hz and V obtained Load-Run Test: Slow-start test demonstrating basic load-carrying capability, equivalent to 90-100%, for not less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
(Fast-) Starting Test: No loading V - Hz within limits, time.
More demanding Pre-Op tests:
Loss-of-Offsite Power (LOOP) Test: LOOP event simulated Start, reach V-Hz within limits, energize auto-connected shut-down loads through load sequencer, operate 5 minutes
Pre-Operational Testing (continued)
Safety Injection Actuation Signal (SIAS) Test: Verify that upon SIAS signal, EDG will start to "running standby" mode with V - Hz in limits, ready to *immediately* accept E-1 loads if LOOP occurs Combined SIAS and LOOP Test: Combines two previous tests.
Largest-Load Rejection Test: Largest single load is shed Stay within acceptable V - Hz limits and not trip out from over-speed.
Design Load Rejection Test: Shed a load = 90-100% of design.
Must not trip out on over-speed No limit on V/Hz .
(See IN 93-96)
Pre-Operational Testing (continued)
Endurance and Load Test: A 24-hour run, with 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at short-time rating and 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> at 90-100% of continuous load rating Hot Restart Test: Immediately after shutting down from a run at full load temps, restart and run 5 minutes Synchronizing Test: Transfer of emergency loads back to normal power. EDG paralleled with grid, loads transferred to offsite power, then EDG isolated from grid and restored to standby.
Pre-Operational Testing (continued)
Test Mode Override Test: With EDG operating in automatic test mode, connected to its bus, a simulated SIAS overrides test mode.
E-1 loads energized from grid, EDG goes into running standby.
Independence Test: Verify that simultaneously starting and running redundant EDGs does not reveal any common failure mode undetectable in single-unit tests.
The EDGs are now operational.
Periodic Tests demonstrate continued readiness:
Periodic Testing (See Figure 11-1)
Availability Test: Slow start and load, monthly. Every 6th month, combined Fast-Start and Load-Run test, which will simultaneously satisfy Availability Test. RG 1.9 System Operation Tests: These verify the EDG's ability to perform under simulated accident conditions. Done at shutdown-refueling outages (approx 2 years). All have been described previously (See Figure 11-1 list)
Periodic Testing (See Figure 11-1)
Independence Verification Test: Required after mods that may affect EDG independence + every 10 years during plant shutdown or refueling outage. Start all redundant units simultaneously.
..PLEASE NOTE .....
Our discussion of EDG testing was based on Table 3 of IEEE 387-1995. There are differences between it and the corresponding Table 1 of RG 1.9 Rev 4 (3-2007). Those are flagged by a ""
symbol on the next slide.
Requirements applicable to each NPP are always determined by site-specific documents and revs the licensee has committed to.
LEGEND X Test in RG 1.9- Rev 4 (Table 1) and IEEE 387-1995 (Table 3)
Test in RG 1.9- Rev 4 only (NRC is "looking into" that)
Figure 11-1 Site Testing of EDGs IEEE 387-1995, Table 3
Records for Each EDG Unit Records shall be maintained and retrievable for each EDG unit, to analyze performance. Used to modify equipment maintenance intervals/replacement schedules. Include:
All start attempt, maintenance, repair, and out-of-service data, operating and maintenance data, statistical analysis of EDG test results and regular demand runs.
Analysis of failure mechanisms, human errors, and common mode failures, with causes and corrective actions included.
Test parameter data per IEEE 387-1995, Table 4 (SM Fig 11-2)
Figure 11-2 Test Parameters IEEE 387-1995, Table 4
Good place for a break!
Concerns about Adequacy of Licensee Testing Refer to Temporary Instruction (TI) 2515/176 - May, 2008:
NRC: Endurance tests at Dresden NPS did not adequately verify EDG operability because loading did not envelop the predicted design-basis event (DBE).
Problem identified at other sites. Issues found in test loading criteria, peak design-basis loading values - durations, and EDG ratings.
TI issued to assess the extent of these issues and evaluate adequacy of EDG tests, per plant-specific TS and design.
Concerns about Adequacy of Testing (continued)
EDG loading is generally designed for a concurrent loss-of-offsite power and a loss of cooling accident, LOOP+(LB)LOCA.
Problem: Some sites have higher calculated loads for a LOOP coincident with a small-break (SB)LOCA, or a main steamline break (MSLB), than the presumptive LOOP+(LB)LOCA.
Timing of these events can also impact load, depending on which occurs first + time interval between "Short-time rating" subject to interpretation. Manufacturers may have several ratings above "continuous" for run intervals of 2000, 4, 2, and 0.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />
Concerns about Adequacy of Testing (continued)
TI 2515/176 requested extensive data for every EDG used as an onsite standby power supply, as the first step in addressing this concern.
Follow-up report ML093370252 - 12 Dec 2009:
- NRC staff evaluated 239 EDGs, found a DBE could load 110 (46%) above their continuous or 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating.
- Concern expressed about impact of extended operation due to extreme weather, natural disaster,
- See report for additional concerns, and recommendations.
NRC Position on the Use of EDGs for Peaking Branch Technical Position ICSB-8 (PSB)
"Use of Diesel Generator Sets for Peaking."
"the potential for common mode failure modes should preclude interconnection of the onsite and offsite power sources except for short periods for the purpose of load testing."
Bottom Line:
Use of EDGs for peaking strongly discouraged Both EDG systems should never be run on grid together (Why?)
EDG Operation on the Grid for Test Three statements summarize this subject, discussed in more detail in 11.10 of your Student Manual:
- 1. Engine "feels" KW load, is not affected by KVAR load except to extent power factor impacts generator efficiency. KW load is increased by governor attempting to increase RPM (generator frequency) by adding fuel. It can't, engine-driven generator is locked in sync with the grid. EDG picks up more KW load.
Reducing engine power, as if trying to slow down, takes off KW load. Eventually power flow may reversegenerator becomes motor driven by grid.
EDG Operation on the Grid for Test (continued)
- 2. Generator "feels" KVA and, therefore, KVAR load. KVAR load increased by voltage regulator attempting to increase gen output voltage (via the field). It can't raise grid voltage!
Generator picks up more KVAR load.
If voltage regulator tries to lower generator output voltage below line voltage a loss-of-field trip occurs.
- 3. To prevent problems: Connect to grid with gen synchronized (but rotating at a slightly higher frequency than the grid) and with gen output voltage slightly above line voltage.
(continued)
EDG Operation on the Grid for Test (continued)
Disconnect will be made before getting too close to no load.
EDG must be in "droop" mode whenever on the grid NOTE: IEEE 387-1995 (4.5.2.2) requires that upon receipt of an emergency start-diesel signal, EDG's automatic control system shall provide automatic start-up, with adjustment of frequency and voltage to a ready-to-load condition, in isochronous mode.
Observations on EDG Surveillance Runs Chapter 11 includes technical information on:
EDG surveillance run Selection, operation of generators for particular loads Impact of abrupt load application/rejection on V and f Too detailed for class Next: Info on "typical" EDG surveillance run "Nuts and bolts" items to help assure a successful test.
Observations on EDG Surveillance Runs As-Found Documentation: "As-found" inspection of EDG and supporting systems. Compare to previous, "as-left" data Pre-Op General Walk-Around: Leaks, other anomalies? If any, tagged, reported, accepted for run?
Verify EDG Support Systems Status:
Fuel and lube oil Pre-lube, lube keep-warm Jacket water keep-warm 125 V dc control and field flash
Observations on EDG Surveillance Runs Starting air, control air pressure, dryness Fire protection system status Combustion air intake and exhaust, room cooling Shutdown trips and lock-outs cleared:
Shutdown relay Overspeed trip Output circuit breaker
Observations on EDG Surveillance Runs Additional checks:
Governor settings, actuator oil level "Bar" / slow-roll engine (cylinder cocks open)
All cylinder cocks closed Governor fuel rack linkages free Confirm governor in droop ("parallel") mode Switch local EDG control from local to remote (for Control Room manual start)
Observations on EDG Surveillance Runs Confirm availability and stability of offsite power system Get approval for start, loading onto utility power grid Turn EDG mode selector switch to manual test Engage START switch to initiate operations run Engine starts Nominal RPM for 60 Hz Record starting time Allow to stabilize, take readings Verify from local operator conditions normal
Observations on EDG Surveillance Runs At electric control panel, turn on synchronizing circuit:
Synchronize with grid, with V and f slightly above grid Gradually increase engine KW load in steps.
(KVAR load can either be ramped or not)
Run a few minutes at each KW step Observations, readings, continue to ramp After KW, KVAR loads reach intended test values, continue to take readings.
Observations on EDG Surveillance Runs Allow to run >1 hour, take set of stabilized readings. Note any abnormal/unacceptable conditions Over several minutes, unload EDG to 10% rated KW. (To keep power factor within normal limits, first unload to 10% KVAR.)
Trip EDG output circuit breaker.
Run a few minutes to cool down.
Shut down Set governor mode to isochronous 60 Hz
Observations on EDG Surveillance Runs Post-Operations Phase:
After 15-30 minutes, open cylinder cocks, "bar" engine. Close cylinder cocks. 13 Align for standby mode. Switch local control to Remote, control room switch to Auto.
Reset trips, clear alarm panels, ensure support systems operable, EDG aligned for standby.
Document actions, "as-left" condition of EDG.
Record whether or not the run met acceptance criteria!
END OF CHAPTER 11*