RA21-043, Cycle 19 Startup Test Report Summary

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Cycle 19 Startup Test Report Summary
ML21196A519
Person / Time
Site: LaSalle Constellation icon.png
Issue date: 07/15/2021
From: Washko J
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RA21-043
Download: ML21196A519 (10)


Text

LaSalle County Station Exelon Generation , 2601 North 21 ** Road Marseilles. IL 61341 815-415-2000 Telephone www.exeloncorp com RA21-043 July 15, 2021 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 LaSalle County Station, Unit 2 Renewed Facility Operating License No. NPF-18 NRC Docket No. 50-374

Subject:

LaSalle 2 Cycle 19 Startup Test Report Summary Enclosed for your information is the LaSalle County Station (LSCS) Unit 2 Cycle 19 Startup Test Report. This report is submitted in accordance with Technical Requirements Manual Section 5.0.b.

LaSalle County Station Unit 2 Cycle 19 began operation on April 17, 2021, following a refueling and maintenance outage. The Unit 2 Cycle 19 core loading consisted of 276 fresh Global Nuclear Fuel GNF-3 fuel bundles, 276 once-burned Global Nuclear Fuel GNF-2 fuel bundles, and 212 twice-burned Global Nuclear Fuel GNF-2 fuel bundles. Also installed in the Unit 2 Cycle 19 reactor were 8 new GE/Reuter-Stokes NA-300 Local Power Range Monitors (LPRMs), and 12 new General Electric Ultra HD Control Rod blades and 2 new General Electric Ultra MD Control Rod blades.

Attached are the evaluation results from the following tests:

- Reactor Core Verification

- Control Rod Friction and Settle Testing

- Control Rod Drive Timing

- Shutdown Margin Test (In-sequence critical)

- Reactivity Anomaly Calculation (Critical and Full Power)

- Scram Insertion Times

- Core Power Distribution Symmetry Analysis

- Reactor Recirculation System Performance

July 15, 2021 U.S. Nuclear Regulatory Commission Page 2 All test data was reviewed in accordance with the applicable test procedures, and exceptions to any results were evaluated to verify compliance with Technical Specification limits and to ensure the acceptability of subsequent test results.

There are no regulatory commitments in this letter. Should you have any questions concerning this report, please contact Mr. Daniel Mearhoff, Regulatory Assurance Manager, at (815) 415-2800.

Respectfully, i~,v(__.,

Jo shko Site resident LaSalle County Station Attachment cc: Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - LaSalle County Station

ATTACHMENT Page 1 of 8 Reactor Core Verification Purpose The purpose of this test is to visually verify that the core is loaded as intended for Unit 2 Cycle 19 operation.

Criteria The as loaded core must conform to the cycle core design used by the Core Management Organization (GNF & Nuclear Fuels) in the reload licensing analysis. Any discrepancies discovered in the loading will be promptly corrected and the affected areas re-verified to ensure proper core loading prior to unit startup.

Conformance to the cycle core design will be documented by a permanent core serial number map signed by the audit participants.

Results and Discussion Core verification was performed concurrently with core load and shuffle the guidance in NF-AA-330-1001, "Core Verification Guideline." The Unit 2 Cycle 19 core verification consisted of a core height, assembly orientation, assembly location, and assembly seating check. Bundle serial numbers and orientations were recorded during the video recorded scans for comparison to the appropriate core loading map and Cycle Management documentation. The core was verified as being properly loaded and consistent with the LaSalle 2 Cycle 19 Core Loading Plan, Revision 8. This was documented in work order (WO)# 4902283-01.

ATTACHMENT Page 2 of 8 Control Rod Friction and Settle Testing Purpose The purpose of this test is to demonstrate that excessive friction does not exist between the Control Rod Blade and the fuel assemblies during operation of the Control Rod Drive (CRD) following core alterations.

Criteria Appropriate acceptance criteria are provided in LOS-RD-SR?, "Channel Interference Monitoring" and include limits on rod settle time. The control rod settle test acceptance criterion is less than or equal to 7 seconds.

Results and Discussion CRD Friction Testing commenced after the completion of the core load verification and single rod subcritical check. All 185 control rods settled in less than 4.4 seconds, which is documented in WO# 4902211-01.

ATTACHMENT Page 3 of 8 Control Rod Drive Timing Purpose The purpose of this test is to check and set the insert and withdrawal speeds of the Control Rod Drives (CRDs).

Criteria LOS-RD-SR5, "Control Rod Drive Timing," preferred beginning of cycle acceptance criteria for the withdraw times (full-in to full-out) is between 45 and 60 seconds and insert times (full-out to full-in) is between 40 and 55 seconds.

Results and Discussion Control rod timing per LOS-RD-SR5 was performed satisfactorily for all 185 CRDMs and is documented in WO# 4902820-01. None of the rod withdrawal speeds were faster or slower than the LOS-RD-SR5 preferred criteria.

ATTACHMENT Page 4 of 8 Shutdown Margin Test Purpose The purpose of this test is to demonstrate, from a normal in-sequence critical, that the core loading has been limited such that the reactor will remain subcritical throughout the operating cycle with the strongest worth Control Rod in the full-out position and all other rods fully inserted.

Criteria In accordance with LTS-1100-1, "Shutdown Margin Determination" and Technical Specifications, if a shutdown margin (SOM) of 0.38% Llk/k + R cannot be demonstrated with the strongest worth Control Rod fully withdrawn, the core loading must be altered to meet this margin. R is the reactivity difference between the core's beginning of cycle SDM and the minimum SDM for the cycle. The R value for Cycle 19 is 0.00% Llk/k per the LaSalle Unit 2 Cycle 19 Cycle Management Report, Revision 7, so a SDM of 0 .38% Llk/k must be demonstrated.

Results and Discussion The beginning of cycle SOM was successfully determined from the initial critical data. The initial Cycle 19 critical occurred on April 17, 2021, on Control Rod 14-19 at position 16, using an A2 sequence. The moderator temperature was 153 °F and the reactor period was 303 seconds. Using LTS-1100-1 and the LaSalle Unit 2 Cycle 19 Cycle Management Report, Revision 7, the SOM was determined to be

1. 732% Llk/k. This was documented rn L TS-1100-1 , Attachment A and WO# 4902281-
01. The SDM was greater than the minimum 0.38% Llk/k that is required to satisfy the Technical Specifications.

ATTACHMENT Page 5 of 8 Reactivity Anomaly Determination Purpose The purpose of this test is to compare the actual and predicted critical rod configurations to detect any unexpected reactivity trends.

Criteria In accordance with NF-LA-715 "Critical Predictions with 3D Monicore," NF-AB-760 "Reactivity Anomaly Determination," and Technical Specifications, the reactivity equivalence of the difference between the actual critical Control Rod configuration and the predicted critical Control Rod configuration and the difference between the actual and predicted reactivity of the Control Rod configuration at full power steady state conditions shall not exceed 1% Lik/k. If the difference exceeds 1% Lik/k, the cause of the anomaly must be determined, explained, and corrected for continued operation of the unit.

Results and Discussion Two reactivity anomaly calculations were successfully performed during the Unit 2 Cycle 19 Startup Test Program. One reactivity anomaly calculation is from the in-sequence critical and the other is from steady state, equilibrium conditions at approximately 100% full power.

The initial Cycle 19 critical occurred on April 17, 2021, on Control Rod 14-19 at position 16, using an A2 sequence. The moderator temperature was 153 °F and the reactor period was 303 seconds. The expected kett supplied by Nuclear Fuels was 1.0025. The actual kett was 1.00482. The resulting anomaly was 0.232% Lik/k. The anomaly determined is within the 1% Lik/k required for BOC conditions as stated in NF-LA-715. This was documented in NF-LA-715, Attachment 3 and WO# 4902273-01.

The reactivity anomaly calculation for full power steady state operation was performed.

The data used was from 99.8% power at a cycle exposure of 316.3 MWD/sT at equilibrium conditions. The expected kett supplied by Nuclear Fuels was 1.0080. The actual kett was 1.0077. The resulting anomaly was 0.03% Lik/k. This value is within the 1% Lik/k criteria of Technical Specifications. This was documented in NF-AB-760, , and WO# 4902282-01.

ATTACHMENT Page 6 of 8 Scram Insertion Times Purpose The purpose of this test is to demonstrate that the Control Rod scram insertion times are within the operating limits set forth by the Technical Specifications.

Criteria In accordance with LOS-RD-SR12, "Scram Insertion Times," and Technical Specifications, the maximum scram insertion time of each Control Rod from the fully withdrawn position (48) to notch position 05, based on de-energization of the scram pilot valve solenoids as time zero , shall not exceed 7.0 seconds. Also, no more than 12 OPERABLE Control Rods shall be "slow" in accordance with the below table. In addition, no more than 2 Operable Control Rods that are "slow" shall occupy adjacent locations.

When the scram insertion time of an operable Control Rod from the fully withdrawn position (48), based on de-energization of the scram pilot valve solenoids as time zero, exceeds any of the following, that Control Rod is considered "slow":

Notch Position Scram Time to Notch Indicated (seconds) 45 0.52 39 0.80 25 1.77 05 3.20 Results and Discussion Scram testing was performed per WO# 4902192-01 . Results of testing are given below.

Notch Position Core Average Scram Times of all CRDs (sec) 45 0.302 39 0.585 25 1.261 05 2.278 Once SCRAM Timing was complete, there were no slow rods. These results also meet the "Option B" Scram Speeds referenced in the Unit 2 Cycle 19 Core Operating Limits Report (TRM Appendix J).

ATTACHMENT Page 7 of 8 Core Power Distribution Symmetry Analysis Purpose The purpose of this test is to verify the core power symmetry.

Criteria In accordance with NF-AB-707, "3D Monicore - Operation and Maintenance," the TIP uncertainty value must be less than 6%.

Results and Discussion Core power symmetry calculations were obtained based upon data obtained from a full core TIP set (OD1) at approximately 100% power. The TIP uncertainty value was 2.80%. This was documented in WO# 5108272-01.

ATTACHMENT Page 8 of 8 Recirculation System Performance Purpose The purpose of this test is to collect sufficient baseline data at the beginning of cycle to establish the following relationships:

  • core thermal power vs. total core flow
  • recirculation total drive flow vs. total core flow
  • core plate flow vs. total core flow
  • recirculation flow control valve position vs. loop drive flow
  • jet pump readings vs. loop drive flow Criteria In accordance with LTP-1600-13 "Recirculation System Performance" and Technical Specifications, the performance curves used in conjunction with reactor recirculation system flow and differential pressure data will establish baseline data to determine if possible jet pump or recirculation pump degradation exists.

The established baseline performance curves will also be used to verify jet pump operability to determine if jet pump anomalies exist.

Results and Discussion Reactor Recirculation data was collected during the L2C19 startup. Data was obtained from computer points for all the points of interest to evaluate the RR System performance . The RR performance curves were updated for L2C19; jet pump performance was improved in the jet pumps that had foreign material removed in comparison to L2C18 . This is documented in WO# 4904311-01 .