RA-11-017, Cycle 23 Startup Test Report
| ML110900062 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/21/2011 |
| From: | Massaro M Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA-11-017 | |
| Download: ML110900062 (12) | |
Text
Oyster Creek Generating Station www.exeloncorp.com Exelkn Nuclear Route 9 South PO Box 388 Forked River, NJ 08731 TS 6.9.1 RA-1 1-017 March 21, 2011 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Oyster Creek Nuclear Generating Station Renewed Facility Operating License No. DPR-16 Docket No. 50-219
Subject:
Oyster Creek Nuclear Generating Station Unit 1 (OCNGS) Cycle 23 Startup Test Report Enclosed for your information is the OCNGS Cycle 23 Startup Test Report. This report is submitted in accordance with Technical Specifications (TSs) Section 6.9.1 due to the introduction of a new fuel design GNF-2 at OCNGS.
OCNGS achieved initial cycle criticality on November 30, 2010, and reached steady state full power for the first time in Cycle 23 on December 30, 2010. Startup testing was completed on January 14, 2011, with the exception of the first sequence exchange. A supplementary report will be submitted following the completion of the first sequence exchange.
The refueling and maintenance activities performed during the 1 R23 refuel outage which may have impacted the fuel design change include: Core offload of 160 GEl 1 spent fuel bundles, Core reload of 160 new GNF-2 fuel bundles, replacement of 4 GE Marathon Control Rod Blades, and replacement of 27 control rod drives.
The 30 tests listed in FSAR Appendix 14.2A, and the two additional tests listed in FSAR Table 14.2A-1, were reviewed to determine their applicability given the scope of the fuel design change.
Attached are the evaluation results from the applicable tests:
- Control Rod Drives
- Fuel Loading
- Shutdown Margin Testing
- Control Rod Sequence
- LPRM Calibration
- Core Performance Testing
- Calibration of Rods
- Axial Power Distribution
- Rod Pattern Exchange
U. S. NRC All test data was reviewed in accordance with implementing test procedures, and exceptions to any result was evaluated to verify compliance with applicable TS limits and to ensure the acceptability of subsequent test results.
Should you have any questions concerning this letter, please contact Declan Doran at 609-971-4367.
Sincerely, Michael J. Massaro Site Vice President Oyster Creek Nuclear Generating Station
Enclosure:
Cycle 23 Startup Report cc: USNRC, Regional Administrator, Region I USNRC, Senior Project Manager, NRR USNRC, Senior Resident Inspector
U. S. NRC Attachment to RA- 11-017 Page 1 of 10 Control Rod Drives Purpose The purpose of this test is to demonstrate that the control rod scram insertion times are within the operating limits set forth by Technical Specifications (TSs).
Criteria The maximum scram time averages are described in TS 3.2.B.3. The average of the scram insertion times for the three fastest control rods of all groups of four control rods in a two-by-two array are compared, along with the full core average scram times. The time requirements are below.
Percent Core Avg 2x2 Array Inserted (%) (sec) (sec) 5 0.375 0.398 20 0.900 0.954 50 2.00 2.120 90 5.00 5.300 Results and Discussions All control rods were exercised to demonstrate normal notching capability prior to plant startup, and all control rods that underwent maintenance were scram time tested prior to startup.
All control rods were scram time tested while reactor pressure was greater than 800 psig and were well within required TS limits. There are no scram time testing requirements for individual control rods, only 2x2 arrays, and full core averages. The results from scram time testing show that the 2x2 arrays and full core averages are satisfactory. The full core average times are listed below.
Percent Core Avg Inserted (%) (sec) 5 0.326 20 0.696 50 1.509 90 2.586 Based upon the review of the scram times, there is no notable trend in scram times since last cycle. Therefore, there is no indication of system or configuration degradation.
U. S. NRC Attachment to RA-1 1-017 Page 2 of 10 Fuel Loading Purpose The purpose of this test is to load new fuel and to shuffle the existing fuel safely to the final loading pattern as intended for Cycle 23.
Criteria The as-loaded conditions for the core must conform to the cycle core design used by the Core Management Organization (Global Nuclear Fuels and Nuclear Fuels) in the reload analysis.
During fuel movement, shutdown margin and Source Range Monitor (SRM) connectivity is to be maintained within TS limits.
Results and Discussions During fuel movement activities, at least two SRMs were operable, one in the quadrant where the core alteration was being performed and one in the adjacent quadrant (TS Section 3.9).
Each fuel bundle remained neutronically coupled to an operable SRM at all times as verified by SHUFFLEWORKS, and Shutdown Margin was verified by Exelon Core Manager (ECM) throughout the shuffle. SRM count rates were recorded after each core component move.
The final loading pattern includes 160 new GNF-2 fuel bundles, 180 once burned GEl 1 bundles, 184 twice burned GEl 1 bundles, and 36 thrice burned GEl 1 bundles. The complete Cycle 23 core consists of all barrier fuel.
Core verification was completed on 11/22/10 in accordance with procedure NF-AA-330-1 001.
To ensure proper fuel loading into the core, the following steps were performed:
- Proper fuel bundle serial number, location and orientation
- Seating verification
- Debris inspection The verified core loading map was compared with the Core Loading Plan and no discrepancies were found.
U. S. NRC Attachment to RA-1 1-017 Page 3 of 10 Shutdown Marqin Testing Purpose The purpose of this test is to demonstrate that the reactor will be subcritical throughout the fuel cycle with any single control rod fully withdrawn and all other rods fully inserted.
Criteria TS 3.A.1 requires that Shutdown Margin (SDM) under all operational conditions shall be equal to or greater than 0.38% delta k/k with the highest worth control rod analytically determined.
OCNGS calculates shutdown margin using an in sequence critical with the strongest control rod analytically determined.
Results and Discussion Shutdown Margin Measurement test was performed by using the in-sequence critical method using Procedure 1001.27. This in-sequence test satisfies the requirement of the FSAR test by measuring the actual SDM value to verify the TS SDM requirements are met.
The Beginning of Cycle (BOC) SDM was calculated by taking the predicted cycle minimum shutdown margin and then subtracting the difference between the predicted critical eigenvalue and the actual critical eigenvalue. This calculated SDM value based upon plant conditions at criticality was equal to 2.21% Ak/k. This value was verified to be greater than the required 0.38% Ak/k as defined in TS 3.2.A
U. S. NRC Attachment to RA- 11-017 Page 4 of 10 Control Rod Sequence Purpose This test is intended to demonstrate acceptable rod worth's result from the sequence being used.
Criteria There are no TSs associated with this test, as this test predates the development of the Bank Position Withdraw Sequence (BPWS).
Results and Discussion The plant uses a BPWS compliant sequence enforced by the Rod Worth Minimizer (RWM) up to 10 % power as allowed by TSs. In-sequence rod worths vary more as a function of the loading than the nuclear fuel type.
BOC criticality was achieved on 11/30/10. The reactor was declared critical at 2022 with RWM Group 4 Control Rod 18-23 at position 20, RWM sequence step 6. Reactor water temperature was 186 degrees F. There were no inoperable control rods and the reactor period was 144 seconds. The actual critical eigenvalue was within .5 mk of the predicted critical eigenvalue.
Final Full power rod pattern was achieved on 1/1/11. All thermal limits remained within their required values.
U. S. NRC Attachment to RA- 11-017 Page 5 of 10 LPRM Calibration Purpose The Purpose of this test is to calibrate the local power distribution monitoring system.
Criteria All operable detectors are to be calibrated, and the gain adjustment factors (GAF) for each Local Power Range Monitor (LPRM) are within procedural requirements (0.80 - 1.20) to be operable.
Results and Discussion A full LPRM calibration using Traversing In-core Probes (TIPs) was performed at 100% power.
The LPRMs were within their TS Calibration interval and therefore the LPRMs were not re-calibrated from the full set of TIP set obtained at 75% Core Thermal Power (CTP). TIPs were obtained so that a GAF file could be created and used for LPRM adaption in 3D MONICORE. A LPRM Calibration was performed on 1/13/11 and 1/14/11 at 100% power and at equilibrium xenon conditions in accordance with OCNGS Procedures 1001.39 and 620.3.009. All operable LPRMs were successfully calibrated during this surveillance.
U. S. NRC Attachment to RA-1 1-017 Page 6 of 10 Core Performance Testina Purpose The purpose of this test is to determine thermal limits, bundle powers, core power, and core flow at various points in the power ascension.
Criteria All core conditions are to remain within the acceptance criteria for normal operations.
Results and Discussion Throughout power ascension, 3D MONICORE cases were manually triggered to provide current core conditions. No thermal limits or core parameters were exceeded during these maneuvers.
U. S. NRC Attachment to RA-1 1-017 Page 7 of 10 Calibration of Rods Purpose The purpose of this test is to obtain reference relationships between rod motion and reactor power in a standard sequence.
Criteria Predicted core conditions (power, recirculation flow, thermal limits, etc) are compared to actual core conditions, and anomalies are to be accounted for prior to raising power.
Results and Discussion During power ascension, 3D MONICORE predictors were routinely performed prior to significant rod or flow maneuvers to provide the operators with the size of expected power change. No anomalies were noted.
U. S. NRC Attachment to RA-1 1-017 Page 8 of 10 Axial Power Distribution Purpose The purpose of this test is to compare axial power distributions between online LPRM adapted conditions, and offline PANACEA conditions Criteria Online LPRM adapted conditions are to be comparable to Off line PANACEA conditions to ensure that the core axial power distribution is accurately modeled. Any deviations are to be analyzed.
Results and Discussion The Axial Power Distribution test was performed comparing Online LPRM adapted 3D MONICORE (3DM) axial power shape to Offline PANACEA axial power shape. Discrepancies were noted in the power shapes, and are discussed below. All results are within TS thermal limits.
Due to a difference in eigenvalue between the actual core reactivity (keff = 1.0071) compared to predicted conditions (keff = 1.0051), the full power steady state rod patterns were different.
More deep control rod notches were withdrawn than originally predicted. This results in more power being generated higher in the core, and conversely less power in the bottom of the core, which is reflected in comparison between predicted vs actual relative power as shown below.
Axial Power Profile 1.6 1.4 0.4 0.2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Axial Node
U. S. NRC Attachment to RA-1 1-017 Page 9 of 10 AXIAL PANACEA 3D MONICORE POWER NODE RELATIVE RELATIVE DIFF POWER POWER 24 0.125 0.153 0.028 23 0.211 0.258 0.047 22 0.478 0.679 0.201 21 0.603 0.817 0.214 20 0.713 0.951 0.238 19 0.807 1.028 0.221 18 0.891 1.061 0.170 17 0.994 1.103 0.109 16 1.103 1.178 0.075 15 1.177 1.223 0.046 14 1.232 1.240 0.008 13 1.266 1.260 -0.006 12 1.277 1.255 -0.022 11 1.285 1.233 -0.052 10 1.286 1.189 -0.097 9 1.287 1.192 -0.095 8 1.305 1.206 -0.099 7 1.337 1.200 -0.137 6 1.376 1.241 -0.135 5 1.407 1.265 -0.142 4 1.392 1.185 -0.207 3 1.249 1.050 -0.199 2 0.914 0.791 -0.123 1 0.285 0.244 -0.041 This difference in the axial power shape did not result in any significant adverse impact to thermal limits compared to predicted plant conditions as shown below.
Thermal PANACEA 3D MONICORE Limit Projected Thermal Actual Thermal Limits Limits MFLCPR 0.723 0.751 MFLPD 0.866 0.825 MAPRAT 0.806 0.781
U. S. NRC Attachment to RA-1 1-017 Page 10 of 10 Rod Pattern Exchange Purpose The purpose of this test is to determine the representative change in basic rod pattern at a high reactor power level Criteria Compare actual core conditions to predicted core conditions to determine correlation between predicted and actual core conditions. Any deviations are to be analyzed.
Results and Discussion The first Control Rod Sequence Exchange is scheduled at -3000 MWD/ST (May 2011). A supplementary report will be submitted following the completion of this exchange.