ML20217C522
| ML20217C522 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 08/01/1994 |
| From: | Levin A NRC (Affiliation Not Assigned) |
| To: | Mcpherson G NRC (Affiliation Not Assigned) |
| Shared Package | |
| ML20217C479 | List: |
| References | |
| NUDOCS 9803270050 | |
| Download: ML20217C522 (7) | |
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f*I UNITED STATES j
j NUCLEAR REGULATORY COMMISSION
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o WASHINGTON, o.C. 20665 0001
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August 1, 1994 MEMORANDUM FOR:
G: Donald McPherson, Senior Thermal Hydraulics and Testing Expert Division of Systems Safety and Analysis THRU:
Timothy E. Collins, Acting Chief Reactor Systems Branch Division of Systems Safety and Analysis FROM:
Alan E. Levin, Senior Reactor Engineer Advanced Reactor Systems Section Reactor Systems Branch Division of Systems Safety and Analysis
SUBJECT:
REPORT ON CORE MAKEUP TANK MATRIX TEST NO. 306 Enclosed is a report on the matrix test #306, performed in the Core Makeup Tank (CMT) test facility at Westinghouse's Waltz Mill site in Madison, PA.
The test was a constant-pressure drain-down test of the CMT, conducted at a pressure of approximately 1100 psia, with a target drain rate of 11 gpm.
The purpose of this test program is to acquire data for the development and validation of Westinghouse's accident analysis computer codes, including WCOBRA/ TRAC, NOTRUMP, and LOFTTRAN/LOFTTR2, and to test the operation of the heated resistance temperature devices (RTDs) to be used as CMT level sensors The CMT test program is a separate-effects test of behavior of f
in the AP600.
the CMT and related components.
1 and 1/8-diameter of the AP600 CMT.The test article is approximately 1/2-height The procedure for test #306 called for the tank to be drained from 100% full to less than 20% full, with steam supplied to the top of the tank to maintain a constant pressure.
Alan Levin and Rick Hasselberg of NRR and Frank Odar of RES monitored testing activities on June 1.
is on temporary assignment to the NRC.We were accompanied Mr. Andrea Orazi of ANPA/ D Our monitoring activities on June 1 included observation of pre-test preparations, the performance of the test, and post-test data review.
We discussed test procedures, instrument calibration procedures, and test validation and quality assurance with the Westinghouse staff.
The Westinghouse testing staff performed professionally and competently, and we were impressed with their knowledge of the facility behavior.
The test ran smoothly, and appeared to satisfy the test objectives.
The lead test engineer for Westinghouse is Mr. Frank Delose.
Mr. Bruce Rarig is Westinghouse's project engineer. Mr. Jon Gilmore is the operating test engineer.
9803270050 900116 PDR ADOCK 05200003 PDR A.
G. Donald McPherson August 1, 1994 Any questions on this report should be directed to Alan Levin,-at 504-2f90, or to Frank Odar, at 415-6500.
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Alan E. Levin, Sr. Reactor. Engineer Advanced Reactor Systems Section Reactor Systems Branch Division of Systems Safety and Analysis cc:
A. Thadani M. Virgilio R. Jones l:
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'I UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D.C. 20086 0001
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ENCLOSURE
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AP600 CORE MAKEUP TAfE TEST PROGRAN - MATRIX TEST #306 TESTING REPORT Introduction This test was one of a series of quasi-steady-state drain-down tests performed in Westinghouse's CMT test facility, which employs a full-pressure,1/2-height,1/8-diameter scaled representation of an AP600 core makeup tank. The facility is located at Westinghouse's Waltz Mill site, near Madison, Pennsylvania. The test conditions specified a constant-pressure drain-down of the CMT test article at a pressure of 1085 psig {UOO psia), with a target drain flow of 11 gpm.
A description of the test and procedures is included in Attachment 1.
The test was monitored by Alan Levin, SRXB lead AP600 test reviewer; Frank Odar, RES/RPSB, and Rick Hasselberg, AP600 Project Manager, NRR/PDST.
The NRC monitors were accompanied by Mr. Andrea Orazi, on assignment to the NRC from ANPA/ DISP, the Italian nuclear regulatory agency, which is participating in a cooperative agreement for passive reactor test monitoring with the NRC.
Based on observation of the test and a preliminary review of selected data, the test appeared to be successful in achieving its objectives; however, it is subject to further detailed review by Westinghouse. The. staff will also review the test data as part of its overall review of the AP600 design certification test program.
Pre-test Briefina We arrived at the Waltz Mill site on the morning of the test and proceeded to the test facility. Since the three NRC monitors had visited the facility previously, it was felt that a detailed facility tour was unnecessary; however, Mr. Orazi was given a brief tour after the test had been completed.
As stated above, the test article is a scaled version of an AP600 CMT, at approximately 1/110 volume scale. The test article contains a scaled steam distributor, similar to that in the AP600 CMT design. Other major components of the facility consist of a steam-water reservoir, which represents the AP600 reactor vessel, and a steam accumulator system, which is used to supply steam
=to the reservoir. Two lines connect the reservoir to the test article.
Originally, one line was to represent the pressurizer-to-CMT pressure balance line (steam line #1),.and the other was to represent the cold leg-to-CMT pressure balance line (steam line'#2). With the removal of the pressurizer balance line from the AP600 design, the original function of steam line #1 was rendered. unnecessary. However, the line has been retained in the CMT test facility, and the. check valves originally in the line have been removed. As a result. the flow resistances of the two lines are approximately the same, and -
-steam line #1 is'still being used to supply. steam to the test article during the drain-down tests. This is being done because steam line #2 extends
- further-into the top of the steam-water reservoir, and, near the end of a l test,.becomes submerged in water that drains from the test article into the reservoir.1 This would aspirate water into the line and interfere with the
' test, while steam line'#1 is able to supply steam throughout the test.
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. The. test-article also incorporates prototypic heat resistance temperature device (RTD) level sensors-that will be used in the AP600 to control actuation
.of the automatic depressurization system.. The test thus serves not only as a thermal-hydraulic experiment, but also as an operational test of the level detection system.
The observation team was briefed on the conduct of the experiment, including facility preparation and heat-up procedures. Attachment 2 is a copy of the
" Test Prerequisites Sheet," which defines the conditions. for the test and other necessary information, such as instrument ranges. When test facility conditions have been established per the target values on the Prerequisites Sheet,:the test-is initiated. We were also shown documentation concerning test acceptance criteria (but were not given copies for our own use, since the
.documentsareinternalWestinghousememoranda). An initial data review is Lcarried out by the site _ test team, to determine if the established acceptance criteria have been met. There are effectively three ways in which a test can be' categorized, on this basis. The first is that the test has met applicable acceptance criteria. The second is that some parameters did not fall within the. range specified in the acceptance criteria, but the test data still have some validity and should be evaluated further. The last is that the test did not meet acceptance criteria and, as a result, the data are rendered invalid.
After the test engineer. submits his report and the data, with his test evaluation, to the Nuclear Safety organization in Monrceville, that
-organization performs a more detailed and thorough evaluation of the data.
If this review raises. questions about the validity of the data, or if Nuclear Safety's requirements are not met, the test may be rerun.
'Throughout.the briefing, during the test, and in review of the data after the test, the test engineering crew demonstrated a detailed understanding of the behavior of the.CMT facility, and were able to answer the NRC's questions comprehensively. We were impressed with the competence and professionalism of the Westinghouse team.
Instrumentation The CMT facility is instrumented with flowmeters, pressure transducers, and thermocouples both in the CMT fluid and at various depths in the CMT walls. A completa instrument list is included in the' test procedure. Also, as noted previously, the heated RTD level sensors planned for use in the AP600 are
- installed in the test article.
Instrumentation is checked out prior to each
- test, and pressure-and differential pressure reference lines are purged and filled as part of the test procedure. We did not perform a quality assurance
. check of the instrumentation: at this. time;.however, based on observation of data during the test'and a brief post-test data review, it appears that the instruments are functioning well'and are providing good data. The
. instrumentation coverage of the facility has been evaluated previously and found to be acceptable.
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Facility Housekeepina The facility is contained within a small building; no other test apparatus is installed in that building. There is no control room, per se; the facility control panel.is installed in an adjacent-building which also contains other equipment. The data acquisition system is PC-based, and sits on a desk next to the conttol panel.
In general, facility housekeeping appears to be good.
.There were no activities in the building with the control /DAS equipment other than those of the test crew.
Both buildings were open to the environment on the day of the test;'however, the weather was clement. Presumably, the buildings may be closed if weather conditions so dictate.
' Preparation Attachments 1 and 2 are the written test procedures and prerequisites sheet for Test 306. When we arrived at the test facility on Wednesday, June 1, instrument checkout and pressure cell purging were in progress.
Test operations were not begun until about 9:00 a.m., after the NRC team arrived.
Test Conduct and Data Recordina The test operations str.ff performed smoothly throughout the test, demonstrating confidence and familiarity with operation of the loop.
- Mr. Jon Gilmore was the facility operator, with Mr. Frank Delose overseeing
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operations. Several other Westinghouse technicians assisted in various
. operations, such as verifying valve operations, venting steam from the facility,' and so forth. The loop operations are considerably simplified compared to a complex integral facility; as a result, one or two persons can control the facility, initiate data acquisition, and monitor the course of the
= test.
Initial operation involved charging the accumulator with steam, up to a pressurenearthatofthetest(1100 psia). After about 1-1/2 hours, when the accumulator had reached about 900 psi, steam was admitted to the steam-water
- reservoir (SWR) to begin to bring the SWR to test temperature and pressure.
.The SWR pressure and temperature and steam accumulator pressure continued to rise gradually.over the next two hours, with the SBWR reaching saturation conditions at 1100 psia at about 12:35 p.m.
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After a final pre-test' loop check,100 seconds of pre-test data collection was initiated.at 12:54 p.m.,'and the test was initiated at 12:56 p.m., by opening the CMT drain. valve.: Some initial oscillations in drain flow were noted; these were expected,. based on the results of previous tests, and resulted from an initial condensation of' steam by the subcooled water at the top of the CMT, e
building up a layer of saturated liquid. The drain flow rate increased rapidly to a value of about 12 gpm, slightly above the target value of 11 'gpm.
~ Over the course of the test, the decreasing head of water in the CMT and the Ereduction on SWR temperature by injection of water from the CMT combined to reduce the.' driving pressure differential for CMT flow, and the drain flow rate
. dropped to under 9 gpm..
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, The CMT drained completely in about 20 minutes, with an average rate of level decrease of about 1/2 ft/ min.- The loop was then depressurized to acquire data on the rate of heat release from the CMT walls. The test was terminated about 30 minutes after its initiation, at about 1:25 p.m.
In terms of the rate-of CMt level decrease, the test conditions were reasonably close to the results observed in integral tests in the SPES-2 facility and in AP600 analyses. Those results show level decreases of the order of about 2/3 ft/ min.
Data were recorded throughout the test, per the test procedure. We did not observe any related problems. We were able to observe selected parameters.on
- a digital display on the data acquisition system (DAS) PC monitor during the test. A very limited number of temperaturas and pressures can be observed, to track CMT level and loop thermal-hydraulic conditions.
Based on these
- observations, it appeared that the test successfully achieved -its objectives.
Data Processino and Quick-Look Reports Data processing is performed essentially concurrent with the test, with data
' in engineering units available for_ examination immediately post-test. Data from the test are plotted the day after the test is performed (this is a recent change in procedure; plotting data had previously taken a substantially longer time and had caused delays in Westinghouse's review of test data). The test engineer prepares a Day-of-Test Report to forward to Monroeville for review by Westinghouse's Nuclear Safety group.
Quick-look reports are planned for issuance to the NRC 30 days after each series of tests.
Post-Test Data Examination We performed a brief post-test data review on-site, immediately after the test.. As noted above, data conversion to engineering units is done as data are taken. The file _can then.be called up on the DAS PC, and examined in tabular form.- On-line plots are not available; however, this capability is planned for future test series.
The data appeared to confirm observations as to the success of the tests from a thermal-hydraulic standpoint.. CMT levels, temperatures, and drain flow behaved approximately as expected during the test. Of particular interest, though, was the response of the prototype heated RTD level sensors.. The
- active'(heated) and. reference-(unheated) temperatures for each probe are-recorded separately (as opposed to.a single differential temperature). The ability of the sensors to track level change can then be estimated using the.
' CMT temperature and. differential pressure measurements. The actual change in temperature difference between the " covered" and " uncovered" states of the sensor is relatively small--less than 10"F, and the response time of the
-.sensor'is relatively long--at least several tens of seconds.
It remains to be-
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. seen how Westinghouse will " condition" the data from these sensors to provide a reliable indication of CMT level for actuation of the automatic depressurization system in the AP600.
General Observations Overall, we found the Westinghouse testing staff to be professional and competent in test facility operations. Westinghouse's staff was also very cooperative in providing information to the NRC's observers and in responding to NRC questions.
Westinghouse has gained considerable experience in operating this _ facility, and turnaround time between tests is very short; several tests are being run each week. Recent information received from Westinghouse has indicated a need for more accurate data on CMT level and flow, which will result in installation of some additional instruments, but the delay in the program should be minimal.
This type of test--strictly separate effects, with almost no system-level interactions--is relatively simple and straightforward. While observation of the test provided good insight into facility operations and capabilities, the information from the test is relatively limited. However, future test series are planned in which interactions, such as concurrent system depressurization and draining, after a period of recirculation, will be studied.
The more complex nature of these tests should provide greater challenges to the test facility and operations staff, and should be of substantially greater interest for observations. A future trip to observe such testing is planned.
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