ML20024B041
| ML20024B041 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 05/22/1983 |
| From: | PUBLIC SERVICE CO. OF COLORADO |
| To: | |
| Shared Package | |
| ML20024B035 | List: |
| References | |
| NUDOCS 8307050008 | |
| Download: ML20024B041 (10) | |
Text
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A THE FORT ST. VRAIN l
INITIAL APPROACH TO POWER TESTS (B-SERIES) l INTERIM REPORT 27 Report for Period Ending May 22, 1983 l
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Interim Report 21 covering the 90-day period from August 23, 1981, to November 22, 1981, reported the completion of the majority of tests at 100% of plant load.
Since the plant has not attained significant power levels for remaining performance tests, no further initial approach to power tests were performed during the 90-day period ending May 22, 1983.
This report does, however, report the closing of another startup series test. During the 90-day period ending May 22, 1983, the results of startup test RT-485 were reviewed and approved by the Nuclear Facility Safety Committee. A summary of the test and the results are included for your review.
Future interim reports will report the results of any startup tests which still remain in the j'open" status.._ _
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-2 PURPOSE /0BJECTIVE The purpose of RT-485 was to install temperature sensors into the control rod drive assemblies located in regions 5, 34, and 36.
A total of five sensors are to be placed in regions 5 and 36, with one additional sensor placed in region 34. Regions 4, 34, and 35 had temperature sensors placed previously for other system tests. These regions plus the new regions stated above comprised the total testing spectrum of RT-485. Sensors will also be placed on certain missile plates and secondary closure plates. Data from all of these sensor points will be analyzed to determine heat load and heat penetration from the core during various power level runs.
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. JUSTIFICATION The modified Fort St. Vrain control rod drives (CRDs) have been in use since additional seals were installed during the summer of 1975.
At that time, thermal heat loads to the penetration liner cooling system were predicted for conditions up to 100% power based on empirical flow testing of individual prototype seals and extensive flow network and heat transfer models.
Prototype seals installed on a CRD and tested in air at Fort St. Vrain confirmed expected seal performance. Subsequent power testing to 28% power in the summer of 1976 produced top head heat loads to the penetration liner about 50 to 80% greater than expected. At that time, a CRD was returned to San Diego f r full scale flow testing. The flow General Atomic in 9
_. _ test agreed well with the existing flow model and only minor flow model parameters were modified. At that time, the added heat load was generally " explained" by assuming higher-than-measured seal leakage and less effective insulation, etc.
The thermal model of the CRD was a 2D model which had limitations in representing flow and conduction paths associated with the control ro,d guide tubes and the reserve shutdown hopper.
Thermal conductivity tests were not conducted due to the uncertainties involved with setup and evaluation of test results for testing in atmospheric air.
. i The existing liner and concrete thermocouples installed in the top head were of little use in determining flow rates and directions within the CRDs.
The liner head load thermocouples produce a head load per penetrations but give no clues as to helium flow direction i
or temperature distribution.
The flow rate can be calculated to balance heat load but only if the thermal conductivity through the control rod guide tubes and reserve shutdown hopper are well known.
There is considerable uncertainty in the contribution of these conduction paths.
The proposed resistance temperature devices were to indicate the metal surface temperature of the orifice drive mechanism mounting plate and the temperature of the gas flowing below this plate. They also measure upper and lower helium environments within the mechanism area of the drive, plus the temperature of the control rod drive motor itself. Analysis of these data provided information with respect to the following:
- 1) Gas flow direction under the plate and flow direction (up or down) in the CRD penetration.
- 2) Improved correlation of gas flow rates.
- 3) Assist in determining whether the increase in heat load is due to higher forced convection or increased thermal conductivity throughout the CRD.
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. 4) Determine the thermal environment of the orifice valve and control rod drive mechanisms.
- 5) There was a remote chance that if core oscillations were related to orifice valve flow / pressure oscillations, that some oscillations may have been detected on the gas temperature sensor.
- 6) The temperature information and related analysis should be of value in the design of other HTGR CRD designs.
RESULTS In general, it was shown that control rod drive mechanism internal temperatures are directly related to the core pressure drop, primary coolant flow rate and the position of the primary coolant flo'w
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orifice. The more closed the orifice, the greater the delta-P, resulting in higher control rod drive mechanism internal temperatures.
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. A total of five regions were monitored during the data gathering for RT-485. Those regions were regions 5,
4, 34, 35, and 36.
In addition, several secondary closure plates and other top head plates were monitored for temperature. There did not appear to be any specific correlation between control rod drive temperatures and plate temperatures beyond that generally associated with increasing temperature due to power rises.
The final data was taken during a 100% power run on November 8, 1981.
The results were analyzeu and reviewed by the Nuclear Facility Safety Committee on April 21, 1983. RT-485 startup test is now considered closed.
STATUS OF B-SERIES ST ARTUP TESTS:
The attached listing of the B-Series Startup Tests shows the individual test numbers, titles, and status.
a
. STATUS OF B-SERIES STEADY-STATE START-UP TESTS SUT TITLE STATUS B1-1 Steam Generator Steady State Closed B1-3 Steam Generator Steady State Closed 1 (Data with Plugged Tube)
B1-4 Steam Generator Steady State Closed 1 (HP Feedwater Heater Bypassed)
B1-6 Turbine Generator Steady State Closed Performance
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Primary Coolant System Impurities Closed ~
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B2-1
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B2-2 Purification Chemical Impurities Closed B2-3 Calibration of Gas Chromatograph Closed 83-1R Liner Cooling Maximum Temperatures
- Closed 83-IS Liner Cooling ADJ (as required)
Closed 1
Steam Generator Steady State data was taken with HP feedwater heater #5 removed from the system. However, both of these SUT's are considered closed. Whenever all feedwater heaters are operational, data will be taken to analyze the complete system.
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. STATUS OF B-SERIES STEADY-STATE START-UP TESTS B3-1Q PCRV Liner Cooling Closed 83-2Q PCRV Data Scan Closed B3-2R PCRV Internal Temperatures Closed B3-3A PCRV Leak Tightness Closed 83-3B Full Pressure PCRV Leakage Closed SR 5.2.1.6a-M (as required)
B4-1(0)
Circulator Primary Coolant Closed B5-1 Nuclear Instrument Calibration (100%) Open B5-2 Core Region TC Calibration Closed B5-3 Feedwater Flow Calibration Closed B ~11 Xenon Stability Test (100%)
Open
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STATUS OF B-SERIES STEADY-STATE START-UP TESTS B12-2 Shielding Survey (100%)
Open*
B13-1 Radioactive Gas Analysis Closed B13-2 Iodine Probe Analysis (100%)
Open RT-485 Control Rod Drive Internal Closed Temperatures (data to be taken at 6% intervals between 70% and 100%)
2 Shielding Survey data was acquired at 100% power.
However, this startup test is still considered open pending final review of results by General Atomic Company and Public Service Company of Colorado.
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JUN 2 71983 STARTl? FI"0RT DISTRIBl* TION
'j Number o f Contes Mr. John T. Collins, Regional Adminis trator 2 (Original of P Letter) tegion IV Muclear Regulatory Comission ill Ryan Plaza Drive iuite 1000
\\rlington. Texas 76011 Di re c to r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 (P Letter)
Jf fice of Management Information and Program Co: trol Nuclear Regulatory Comnission fashington, D.C.
20555 71 rector - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
25 (P Letter)
)f fice of Inspection and Enforcement
';uclear Regulatory Commission
?ashington. D.C.
20555 tr. Philip C. Wagner, Project Manager 1 (P Letter)
Region IV Nuclear Regulatory Comission ill Ryan Plaza Drive suite 1000 trlington, Texas 76011 N p a r tme n t o f E ne r gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter) tr. Glen A. Newby, Chief iTR Branch 31 vision of Nuclear Power Deve'.opment tail S tation B-107 lashington, D.C.
20545
' tr. Mike Do lphin - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)
FSV, GA Technologies. Inc. Site Representative
'A Technologies, Inc.
L6864 Weld County Road 10 1/2
'latteville. Colorado 80651
- RC Resident Site Inspector - -------------------------
1 (P Letter)