NG-05-0516, Startup Test Report for Extended Power Uprate - Phase II
| ML052860202 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 09/29/2005 |
| From: | Vanmiddlesworth G Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NG-05-0516 | |
| Download: ML052860202 (20) | |
Text
NMC Committed to Nuclear Exellence Duane Arnold Energy Center Operated by Nuclear Management Company, LLC September 29, 2005 NG-05-0516 Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Duane Arnold Energy Center Docket 50-331 License No. DPR-49
Subject:
Startup Test Report for Extended Power Uprate - Phase II In accordance with the Duane Arnold Energy Center (DAEC) Updated Final Safety Analysis Report (UFSAR), Revision 17, Section 17.2.14.6 commitments, Nuclear Management Company, LLC hereby submits the Extended Power Uprate (EPU) Startup Test Report -
Phase II. This report summarizes the startup testing performed on the DAEC following implementation of EPU Phase II modifications during the recent refueling outage (RFO19).
Testing was conducted over the period from June 13, 2005 to June 30, 2005. No problems were encountered during the testing and the final results of the testing and data gathering demonstrated successful operation at the Phase II target power level of 1840 MWt.
Follow-up reports will be submitted in accordance with UFSAR 17.2.14.6, as testing is completed for the subsequent phase(s) of the EPU implementation.
This letter contains no new commitments and no revisions to existing commitments.
Gary n Middlesworth Site Vice President, Duane Arnold Energy Center Nuclear Management Company, LLC Enclosure cc: Administrator, Region ll, USNRC Project Manager, Duane Arnold Energy Center, USNRC Resident Inspector, Duane Arnold Energy Center, USNRC 3277 DAEC Road
- Palo, Iowa 52324-9785 Telephone: 319.851.7611
ENCLOSURE DUANE ARNOLD ENERGY CENTER EXTENDED POWER UPRATE STARTUP TEST REPORT PHASE - II September, 2005 Prepared by: (23 2I Roget. Browning Reviewed by: d c A1Xh J. Roderick Power Uprate Test Coordinator Reviewed by: ____ ___
Stephen D. Kottenstette Power ra Test Coordinator Approved by: I1z W.Olenn Rushworth Chairman, Power Uprate Expert Panel
Duane Arnold Energy Center Extended Power Uprate Startup Test Report Phase - II Table of Contents Section Pape 1.0 Executive Summary 1 2.0 Purpose 2 3.0 Program Description 2 4.0 Acceptance Criteria 3 5.0 EPU Startup Test Program Summary 3 6.0 Testing Requirements 4 6.1 UFSAR Section 14.2 Tests Required for EPU - Phase II 4 6.2 Additional Tests 11 6.3 Industry Operating Experience with EPU 13 7.0 References 14 Tables 1 Test Matrix - Phase I 15 2 Test Conditions - Phase II 16 Figures 1 DAEC Power/Flow Operating Map for EPU 17 i
Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II 1.0 Executive Summary The Duane Arnold Energy Center (DAEC) Extended Power Uprate (EPU) Startup Test Report is submitted to the Nuclear Regulatory Commission (NRC) in accordance with regulatory commitments contained in the DAEC Updated Final Safety Analysis Report (UFSAR), Section 17.2.14.6. The report summarizes the startup testing performed as part of the implementation of EPU. EPU was approved by the NRC in Operating License Amendment No. 243 on November 6, 2001.
DAEC was previously licensed to operate at a maximum reactor power level of 1658 MWt. The result of EPU is a licensed power increase of 15.3% to a new maximum of 1912 MWt. The DAEC is implementing the EPU in planned phases that support a schedule for the necessary modifications needed to achieve the full EPU. The current phase, Phase II, has a target power level of 1840 MWt, a 2.8%
increase in thermal power over the Phase I power level of 1790 MWt. The startup test report for Phase I can be found in Reference 1.
All testing specified in the DAEC UFSAR Section 14.2 have been addressed and evaluated for applicability to EPU, Phase II (Ref. 2). Special test procedures were written and implemented in combination with existing surveillance test procedures, as described in this report. All required tests were completed up to the target power of 1840 MWt. Testing was conducted over the period from June 13, 2005 to June 30, 2005. Test results were reviewed by an Expert Panel for acceptability. No equipment problems were encountered during the testing and the final results of the testing and data gathering demonstrated successful operation at the Phase II target power level of 1840 MWt.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II 2.0 Purpose In accordance with UFSAR Section 17.2.14.6 requirements, this report summarizes the testing performed following the implementation of the DAEC EPU, approved as Amendment #243 to Operating License DPR-49. While Amendment # 243 approved a new licensed thermal power limit of 1912 MWt, an increase of 15.3%, the implementation of the EPU is being conducted in planned phases. This report summarizes the testing performed as part of Phase II, which resulted in a steady-state operating thermal power of 1840 MWt, a 2.8% increase in thermal power over the Phase 1 power level of 1790 MWt. Each test performed is described in Section 6.0 of this report. Follow-up reports, as required by UFSAR Section 17.2.14.6, will be made as the subsequent phases are implemented and core thermal power is increased up to the licensed limit.
3.0 Program Description The EPU startup testing program requirements were developed primarily from:
- Review of the original startup testing program, as described in UFSAR Section 14.2;
- Section 10.4 of the DAEC Power Uprate Safety Analysis Report (PUSAR), NEDC-32980P;
- General Electric (GE) Uprate Test Program recommendations.
The in-plant testing was begun on June 13, 2005, shortly after startup from Refuel Outage 19 (RFO19) on May 3, 2005, and was completed on June 30, 2005. The results of the testing verified the unit's ability to operate at the Phase - II target power level of 1840 MWt.
All startup testing specified in UFSAR Section 14.2 have been evaluated for applicability to the EPU testing program (Ref. 2). Special Test Procedures (SpTPs) were written to coordinate and control the startup testing program. Where possible, the testing program took credit for existing Surveillance Test Procedures (STP).
The majority of the testing falls within the following categories:
- Verification that the control systems (i.e., Condensate and Feedwater and EHC-Pressure Regulation) are stable at uprated conditions.
- Collection of system performance data to verify modifications made to support EPU operation were performing as expected.
- Collection of general plant data (i.e., radiation surveys, coolant chemistry, thermal performance) for comparison to previous plant rated conditions.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II Table 2 presents the Test Conditions at which startup testing was performed in Phase II. Reactor core flow could be any flow within the safe operating region of the power/flow map (Figure 1) that will produce the required power level. Testing at a given power level was completed and thoroughly reviewed prior to proceeding to the subsequent Test Condition. Test results were reviewed by an Expert Panel, a multi-disciplinary group, chaired by the Operations Manager, who made the recommendation to the Plant Manager that it was acceptable to increase power and proceed to the next Test Condition.
4.0 Acceptance Criteria For each recommended test, individual test abstracts will define the purpose of the test, the appropriate test conditions and the associated acceptance criteria.
Test criteria for each test have up to two levels of importance. The criteria associated with plant safety are classified as Level 1. The criteria associated with design expectations are classified as Level 2.
- 1. Level 1 Variable or Criteria Data trend, singular value, or information relative to a Technical Specifications margin and/or plant design in a manner that requires strict observance to ensure the safety of the public, safe operation of the plant, continued operation at power, worker safety, and/or equipment protection.
Failure to meet Level 1 criteria constitutes failure of the specific test. The plant must be placed in a safe condition, based upon prior testing, until the problem is resolved, and the test is satisfactorily repeated, if necessary.
- 2. Level 2 Variable or Criteria Data trend, singular value, or information relative to optimizing system or equipment performance that does not fall under the definition of Level 1 criteria.
Level 2 criteria do not constitute a test failure or acceptance; they serve as information only. It is not required to repeat a test due to a Level 2 criterion failure.
5.0 EPU Startup Test Program Summary Post-modification testing was performed as part of startup from RFO19 on May 3, 2005 and baseline data was collected during power ascension to the Phase I steady state power level of 1790 MWt. The EPU Phase II test program was begun 3
Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II on June 13, 2005 and the final test data at 1840 MWt was completed on June 30, 2005. The Expert Panel did an initial review of the test data for anomalies on July 5, 2005. The Expert Panel final review of the last set of data was conducted on July 25, 2005 and the formal report to the Plant Manager recommending continued steady state operation at the Phase II target power level of 1840 MWt was made on August 15, 2005.
As discussed in Section 6.1, based upon review of test data at lower power levels, the test matrix at higher power was simplified and some test steps were not performed, as they would not have provided useful data.
The completed testing at the Phase II target power level of 1840 MWt demonstrated stable plant operation. Changes in plant chemistry and radiological conditions were minor, vibration measurements of main steam and feedwater piping were acceptable, and no plant equipment anomalies were noted.
6.0 Testing Requirements Each of the Startup tests discussed in UFSAR Section 14.2 has been evaluated for applicability to EPU (Ref. 2). Pre-operational tests used to confirm construction of systems was per design are excluded and not discussed further. Several tests performed in EPU Phase I (Ref. 1) were not required to be re-performed in Phase II (Ref. 2). Throughout the following discussion, the test numbers and titles are consistent with the original Startup Test Specification.
Section 6.1: This section identifies each Section 14.2 test required to be performed for EPU. The purpose of the test, a description of the test, Acceptance Criteria, and the test results are included.
Section 6.2: This section identifies additional test/data collection that was performed to assess the performance of the unit at EPU conditions. The purpose of the test, a description of the test, and the test results are included.
Section 6.3 This section identifies additional activities conducted based upon recommendations from industry operating experience with EPU.
Table 1 identifies the tests/activities conducted as part of Phase II. Table 2 presents the Test Conditions for Phase II.
6.1 UFSAR Section 14.2 Tests Required for EPU- Phase II 6.1.1 Test No. 1 - Chemical and Radiochemical Monitoring 4
Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II
Purpose:
The purpose of this test is to maintain control of and knowledge about the quality of the reactor coolant chemistry and radiochemistry at EPU conditions.
Description:
Samples were taken and measurements were made at the uprated conditions to determine 1) the chemical and radiochemical quality of reactor water and reactor feedwater and 2) gaseous release.
Test Conditions: 1, 2, and 3 Acceptance Criteria:
Level 1: a) Chemical factors defined in the Technical Specifications, Fuel Warranty, and Technical Requirements Manual are maintained within the limits specified.
b) The activity of gaseous and liquid effluents conforms to license limitations.
Level 2: Water quality is known at all times and remains within the guidelines of the water quality specifications.
Results: All Acceptance Criteria were met at all Test Conditions. No abnormalities were observed.
6.1.2 Test No. 2 - Radiation Monitoring
Purpose:
The purpose of this test is to monitor radiation at the EPU conditions to assure that personnel exposures are maintained ALARA, that radiation survey maps are accurate and that radiation areas are properly posted.
Description:
Gamma dose rate measurements and, where appropriate, neutron dose rate measurements were made at specific limiting locations throughout the plant to assess the impact of EPU on actual plant area dose rates. UFSAR radiation areas will be monitored for any required posting changes.
Test Conditions: 1, 2, and 3 Acceptance Criteria:
Level 1: The radiation doses of plant origin and the occupancy times of personnel in radiation areas shall be controlled consistent with the guidelines of The Standard for Protection Against Radiation outlined in IOCFR20.
Level 2: Not Applicable.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II Results: Radiation surveys were conducted with hydrogen water chemistry in service. The general plant dose rates were comparable to those experienced at the previous (Phase I) power level. Dose rates near the main steam piping increased proportional to the power increase (2-3%),
as expected. Radiation dose rates remain compliant with all applicable regulatory limits.
6.1.3 Test No. 19 - Core Performance
Purpose:
The purpose of this test is to measure and evaluate the core thermal power and fuel thermal margin to ensure a careful, monitored approach to the EPU level.
Description:
Core thermal power was measured using the current plant methods of monitoring reactor power. Demonstration of the fuel thermal margin was performed and was projected to the next test condition to show expected acceptance margin and was satisfactorily confirmed by the measurements taken at each test condition before advancing further.
Test Conditions: 1, 2, and 3 Acceptance Criteria:
Level 1: a) Average Planar Linear Heat Generation Rates (APLHGR) shall be less than or equal to the limits specified in the Core Operating Limits Report (COLR).
b) Minimum Critical Power Ratios (MCPR) shall be greater than or equal to limits specified in the COLR.
c) Maximum Linear Heat Generation Rate (LHGR) shall be less than or equal to the limits specified in the COLR.
c) Steady-state reactor power shall be limited to values on or below the Maximum Extended Load-Line Limit Analysis (MELLLA) upper boundary.
d) Core flow shall not exceed its rated value.
Level 2: Not Applicable.
Results: Per normal operating practices, thermal limits are continuously monitored during power ascensions. Specific core monitoring cases were performed at the specified Test Conditions. Projections at the next Test Condition were made to determine if adjustments in control rod position would be necessary to maintain thermal limits within Acceptance Criteria. By adjusting the control rod patterns in the core, as needed, the Acceptance Criteria were met at all power levels.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II 6.1.4 Test No. 22 - Pressure Regulator
Purpose:
The purposes of this test are to:
a) confirm the adequacy of the setting for the pressure control loop used in the analysis of the transients induced in the reactor pressure control system using the pressure regulators, b) demonstrate the takeover capability of the backup pressure regulator upon failure of the controlling pressure regulator and to set spacing between the setpoints at an appropriate value, c) demonstrate smooth pressure control transition between the control valves and bypass valves when reactor steam generation exceeds steam used by the turbine, and d) demonstrate that other affected parameters are within acceptable limits during pressure regulator induced transient maneuvers in preparation for operation at uprated conditions.
Description:
The pressure regulator system tuning was verified to be within the guidance of Service Information Letter (SIL) 589, "Pressure Regulator Tuning."
The backup regulator test was not required to be performed in Phase II, as the maximum power level for this test (1540 MWt) was reached in Phase L.
During testing, step changes in reactor pressure, of increasing magnitude (+/-1 to 2 psi, +3 to 4 psi, +/-5 to 6 psi, +/- 7 to 8 psi, and +/-9 to 10 psi), were simulated, and the resulting transients were recorded. The data for each step change were analyzed for acceptable performance and scram margins prior to performing the next increased pressure step change. Step changes were first performed with pressure regulator "A" in control and second with pressure regulator "B" in control.
Test Conditions: 1, and 3 Acceptance Criteria:
Level 1: The transient response of the turbine inlet (throttle) pressure to any test input must not diverge.
Level 2: a) The decay ratio of the turbine inlet (throttle) pressure must be less than or equal to 0.25. (This criterion does not apply to tests involving simulated failure of one regulator with the backup regulator taking over.)
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II b) The pressure response time from initiation of pressure setpoint change to the turbine inlet (throttle) pressure peak shall be less than 10 seconds.
c) Pressure control system deadband, delay, etc., shall be small enough that steady state limit cycles (if any) shall produce steam flow variations no larger than +/- 0.5 percent of rated steam flow.
d) The peak neutron flux and peak vessel pressure shall remain below the scram settings by 7.5 percent and 10 psi, respectively, for all pressure regulator transients.
e) The variation in incremental regulation, over the range from approximately 10% to 100% of rated core thermal power, shall meet the following:
Percent Steam Flow Variation 0% to 85% <4: 1 85% to 97% <2: 1 97% to 99% <5:1 Results: Based upon the successful "A" controller tests at Test Condition 1, the "B" controller tests for +3 to 4 psi and + 7 to 8 psi step changes were not performed. Similarly at Test Condition 3, the +3 to 4 psi and + 7 to 8 psi test steps were not performed for either "A" or "B" controllers.
All Level 1 and Level 2 Acceptance Criteria were satisfied. The system response to step changes at each power level was satisfactory. No signs of divergence occurred. Pressure response time and margins to scram setpoints were adequate in all test cases. System linearity was confirmed.
6.1.5 Test No. 23 - Feedwater System 6.1.5.1 Test No. 23C - Feedwater Control System (Step Changes in Level)
Purpose:
The purposes of this test are to adjust the feedwater control system for acceptable reactor water level control and to demonstrate stable reactor response to subcooling changes.
Description:
Small step changes in reactor water level (+1, +2, +3, and +5 inches) were inserted to evaluate level control stability and any oscillatory response. These step changes were performed in both "A" and "B" Level Control and each set in both single-element and three-element control. A total of 32 level setpoint change tests were planned at each Test 8
Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II Condition. System responses (steamflow, feedflow and vessel water level) were monitored for overall stability.
Small step changes in system flow were introduced by making level adjustments (+/-1 and +/-2 inches) with the Master Feedwater Regulating Valve (FRV) in Automatic, and one individual FRV controller in Automatic and the other FRV controller in Manual. The tests were repeated with the individual FRV controller settings reversed. A total of 8 system flow tests were planned at each Test Condition.
System responses (steamflow, feedflow and vessel water level) were monitored for overall stability.
Test Conditions: 1, 2, and 3 Acceptance Criteria:
Level 1: The transient response of any feedwater level control system related variable to any test input must not diverge.
Level 2: a) Level control system-related variables may contain oscillatory modes of response. In these cases, the decay ratio for each controlled mode of response shall be less than or equal to 0.25.
b) Following a +/- 3 inch level setpoint adjustment in three element control, the time from the setpoint change until the level peak occurs shall be less than 60 seconds without excessive feedwater swings (changes in feedwater flow greater than 25% of rated flow).
Results: Based upon previous test results from Phase I, the test matrix was simplified at Test Conditions 1, 2, and 3 by omitting the +/-1, +2, and +/- 5 inch level setpoint change tests, i.e., only the +/-3 inch tests were performed, as they have the explicit Level 2 acceptance criterion. Also, given the similarity of response between "A" and "B" level control tests, the "B" single element level control test was not performed at Test Condition 3.
In addition, for the system flow step change tests at Test Condition 3, only the +/-2 inch step was performed.
All tests performed met the Acceptance Criteria. At no time was unstable control system behavior observed and response time was within the 60-second criterion.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase -II 6.1.5.2 Test No. 23D - Feedwater Flow Element Calibration
Purpose:
The purpose of this test is to confirm acceptable calibration of the feedwater flow elements at uprated power conditions.
Description:
In order to verify accurate feedwater flow input to the process computer, feedwater flow data from the flow elements will be compared against a known flow source information (i.e., the ultrasonic flow meter).
Test Conditions: 1, 2, and 3 Acceptance Criteria:
Level 1: Not Applicable.
Level 2: The accuracy of the feedwater flow venturi indication relative to the calibrated flow information shall be within acceptable tolerance for flow rates between 20 and 125 percent rated. The process signal noise shall be within acceptable tolerance of rated flow.
Results: The venturies were within the required tolerances at each Test Condition. No anomalies were observed.
6.1.6 Test No. 25E - Main Steam Flow Element Calibration
Purpose:
The purpose of this test is to confirm acceptable calibration of the main steam flow elements at uprated power conditions.
Description:
In order to verify accurate steam flow input to the process computer, steam flow data from the flow elements will be compared against a known flow source information.
Test Conditions: 1, 2, and 3 Acceptance Criteria:
Level 1: Not Applicable.
Level 2: The accuracy of the main steamline flow venturi relative to the calibrated feedwater flow shall be within +/- 5 percent of rated steam flow at flow rates between 20 and 125 percent 10
Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II rated. The process signal noise shall be within +/- 5 percent of rated steam flow.
Results: The main steamline flow venturies were within the required tolerances at each Test Condition. No anomalies were observed.
6.2 Additional Tests 6.2.1 Steady-State Data Collection
Purpose:
To obtain steady-state data of important plant parameters during EPU operation.
Description:
Plant parameters, both Nuclear Steam Supply System (NSSS) and Balance of Plant (BOP) were recorded at various Test Conditions and evaluated for anomolous behavior prior to increasing power to the next Test Condition.
Test Conditions: 1, 2, and 3 Results: This data was gathered during Summer conditions (i.e., high ambient temperature and humidity), which are more demanding on most plant equipment. Review of the plant data did not identify any anomalous behavior.
6.2.2 Power Conversion System Piping Vibration Monitoring
Purpose:
The purpose of this test is to gather vibration and displacement measurements on the Main Steam and Feedwater (FW) system piping to evaluate the vibration stress effect due to the EPU.
Description:
During the EPU power ascension, locations on Main Steam and Feedwater piping, coincidental with those in the initial startup vibration measurements report or evaluated as representative of the piping system, were monitored for vibration. Vibration measurements taken above that of the previous test will permit a thorough assessment of the impact of EPU.
Subsequent to Phase I, additional vibration monitoring points and associated acceptance criteria were generated for the Feedwater system piping. Specifically, nine additional monitoring points were added on the FW pump discharge piping and FW Regulating Valve areas for Phase II.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II Test Conditions: 1, 2, and 3 Results: After startup from RFO19, three of the original 38 sensors failed - 2 on the Main Steam piping and 1 on the FW piping system. The loss of data from these 3 sensors was evaluated and determined to not impact the overall ability to monitor for excessive piping vibration.
Screening criteria (frequency and magnitude) are established for evaluating the vibration data. If the "Negligible" values in the screening criteria are exceeded, Engineering evaluation of the data is required.
Only two locations, both on the main steam piping, exceeded the Negligible level. The Engineering evaluation determined that the high response is found at 60 Hz and is believed to be from transient electrical response on the cabling and is not a result of actual piping vibrations.
All other vibration data was within the Negligible range.
It should be noted that during Phase II of EPU, modifications were made to the Condensate pumps and motors to allow for a higher feedwater flow capability necessary to achieve the target power level of 1840 MWt. The change in pump characteristics, in particular, pump vane passing frequency, was known to impact the vibration characteristics of the piping systems. Thus, this piping was targeted for monitoring as part of post-modification testing of this modification. Results of this monitoring follow:
The vibration at the critical location on the "A" FW pump 6-inch recirculation piping was flagged as a follow-up issue for Phase III. The values of the measured vibration at the critical location on the 6-inch piping were 70%, 79% & 87% of the allowable vibration values at Test Conditions 1, 2, and 3, respectively.
During general plant observations right after plant restart from RFO19, the 3-inch condensate reject line was observed by Operations personnel as having high amplitude vibration. Engineering evaluation determined that no immediate problem with the vibration existed and developed acceptance criteria for monitoring the piping during power ascension for Phase II. The measured vibration values at the critical location on the piping was 77%, 56% & 33% of the established allowable limit at Test Conditions 1, 2, and 3, respectively. No further action is warranted for Phase III.
During general plant observations right after plant restart from RFO19, a 1-inch drain line was observed as having high amplitude vibration.
Subsequent evaluation determined that a U-bolt had broken off the piping supports. This was repaired. However, at Test Condition 3, the 12
Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II replacement U-bolt was found to be broken and the high amplitude vibration had returned. The measured vibration value at Test Condition 3 was 99% of the allowable (endurance) limit. This has been entered into the Corrective Action Program to design a permanent fix for this vibration.
6.2.3 General Service Water (GSW) Heat Exchanger Performance Monitoring
Purpose:
To gather data on GSW system performance to optimize cooling capacity to individual components.
Description:
Obtain GSW flow (ultrasonic), GSW inlet temperature (contact pyrometer), GSW outlet temperature, and throttle valve positions for various component heat exchangers. The GSW system piping was replaced for EPU with piping of a larger size to increase the cooling to critical components, such as generator stator hydrogen cooling. This testing was to confirm adequate cooling and to provide data for further system balancing (i.e., optimize cooling to critical components.)
Test Conditions: 1, 2, and 3 Results: The data was collected during Summer conditions (i.e., high ambient temperatures and humidity), which are the most challenging for cooling.
Review of the data indicates that all components were receiving adequate cooling.
6.3 Industry Operating! Experience with EPU 6.3.1 Steam Dryer Inspections and On-line Monitoring (SIL 644, Rev. 1)
While not part of the formal EPU Startup Test Program, the results of the steam dryer inspections and subsequent on-line monitoring of moisture carryover is a key attribute of demonstrating safe and reliable operation at uprated power levels.
Service Information Letter (SIL) 644, Rev. I provides the latest recommendations for performing these inspections and on-line monitoring.
Steam dryer inspections were conducted, per the SIL, during RFOl9. These inspections did not find any major problems, only minor indications in the drain channel and a single indication in the cover plate upper support ring, which is consistent with BWR operating experience prior to EPU operation. The likely cause of the DAEC dryer indications is Intergranular Stress Corrosion Cracking (IGSCC), which is not power level dependent. In addition, the indications identified by the inspections performed during RFO1 8 were specifically re-13
Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II inspected and evaluated during RFOI9. None of the previous indications were found to have propagated further. A Justification for Continued Operation (JCO) was prepared that concluded plant startup and operation with the existing dryer cracking was acceptable for the upcoming (i.e., current) operating cycle. The DAEC dryer will be re-inspected during the next refuel outage, currently scheduled for February 2007.
After startup from RFO1 9, moisture carryover measurements were conducted at the Phase I power level (1790 MWt) at least weekly to establish a baseline for future use. In addition, nine measurements were taken at the Phase II power level (1840 MWt). There is no significant increasing trend (statistically or qualitatively) in this moisture carryover data, thus there is no indication of steam dryer damage (per the guidelines of SIL 644, Rev. 1, Appendix D). Periodic monitoring will continue during the operating cycle.
7.0 References
- 1. NMC letter, "Startup Test Report for Extended Power Uprate - Phase I," NG-02-0187, March 4, 2002.
- 2. NMC letter, "Response to Request for Additional Information Regarding License Amendment Request (TSCR - 056): "Elimination of License Condition 2.C(2)(b) for Performance of Large Transient Tests for Extended Power Uprate," NG-04-0478, August 9, 2004.
- 3. NRC letter, "Duane Arnold Energy Center - Issuance of Amendment Re:
License Amendment Request TSCR-056, Modify License Condition 2.C.(2)(b) to Eliminate Main Steam Isolation Valve Closure Test for Extended Power Uprate (TAC No. MC2320)," March 17, 2005.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II Table 1 Test Matrix - Phase II Test Test Title Test Conditions (% of OLTP - 1593 MWt)
No. 112.4 114.3 115.5 1790 MWt 1820 MWt 1840 MWt 1 Chemical and Radiochemical X X X Monitoring 2 Radiation Monitoring X X X 19 Core Performance X X X 22 Pressure Regulator c) Step Changes in X X Pressure 23 Feedwater System c) Step Changes in X X X Level d) FW Flow Element (a) X X Calibration (a) X 25 Main Steam Isolation Valves b) Full MSIV Closure (b)
Test _ _ _
e) Flow Element (a) X X Calibration General Plant Data X Collection Steam and Feedwater Piping Vibration X X X Monitoring General Service Water (GSW) Heat Exchanger (a) X X Performance Monitoring Steam Dryer l Inspections and (c) X X On-line Monitoring (SEL 644, Rev. 1) l (a) Previously performed as part of Phase I testing program.
(b) Per License Amendment # 257, this test is no longer required to be performed. (Reference 3)
(c) Steam Dryer Inspections were conducted during RFOl9.
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Duane Arnold Energy Center Extended Power Uprate Startup Test Report, Phase - II Table 2 Test Conditions - Phase II Test Condition Thermal Power % of Current Licensed % of Original Rated Thermal (MWt) Power Level (1912 MWt) Power (1593 MWt) 1 1790 93.6 112.4 2 1820 95.2 114.2 3 1840 96.2 115.5 16
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