ML20023B666
| ML20023B666 | |
| Person / Time | |
|---|---|
| Site: | 05000128 |
| Issue date: | 04/13/1983 |
| From: | Jennings F TEXAS A&M UNIV., COLLEGE STATION, TX |
| To: | |
| Shared Package | |
| ML20023B650 | List: |
| References | |
| NUDOCS 8305050257 | |
| Download: ML20023B666 (16) | |
Text
{{#Wiki_filter:. s , COMPLETION AND RESULTS OF PHASE I 0F THE NSCR POST DAMAGE PULSE TEST PROGRAM FOR A FULL FLIP TRIGA CORE APRIL 1983 RSB Review and Aporovals:
- a. Phase I Report Review (FeenanW denningy e=[-
#-/ 3 -8 2 Date Chairman, RSB
- b. Approval to proceed with w v. ^
4-/ 3 - % '3 Pulse Test Program Feenan Jenn Chairman,RS@B s b Date l
- c. Approval of Changes to g _, g _3, Phase II and III of the Feenan Jenryffgs Date Pulse Test Program Chairman, RSB 8305050257 830429 DR ADDCK 05000 2
m . Completion and Results of Phase I of the NSCR Post Damage Pulse-Test Progran I. Introduction On 21 February 1983 Fhase I of the NSCR post damage pulse test program was initiated using Core VIII (see Figure 1) and a total of sixteen pulses were completed. Although the original Phase I program called for pulses of up to $2.00 in reactivity it was necessary to stop at $1.85 pulse reactivity insertion based on the peak core temperatures being obtained. It was decided by NSC management to perform an early inspection and measurement of certain fuel elements of interest as six pulses had resulted in peak 0 core temperatures above 1200 F (649 C). A peak core temperature of 1330 F (721 C) was obtained for $1.85 pulse reactivity insertions. The inspection of fuel was completed on 24 February 1983 with no detection of fuel damage, and in accordance with the requirements of the test program this report is presented to the Reactor Safety Board for review and for approval to proceed with the pulse test program. Revisions to Phase II and III of the initial pulse test program are also presented for review and approval (see Appendix I). II. Initial Conditions Prior to initiating Phase I, reactor operations personnel involved in the pulse test program were required to demonstrate proficiency in operating the reactor in the pulse mode. This requirement was met by having these individuals attend a lecture series on the theory of pulse operations and procedural requirements. In addition each was required to simulate pulse operations on the reactor console and to satisfactorily pass a written exam. It was also verified that reactor pulse instrumenta-tion was operational and the mechanical pulse stop for $2.00 pulse insertion limiting value was installed. NSCR Memorandum #161, established to implement Phase I, was reviewed by individuals involved prior to pulsing.
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9 III. Phase I Pulsing Results The sixteen pulses completed ranged from $1.00 to $1.85 reactivity insertion, and a summary of the data obtained is provided in Table I. As can be seen the pulse reactivity values were increased incrementally and comparisons of observed temperatures and energy were made for reproducibility as the program progressed. The peak core temperature was determined for each pulse by applying power peaking factors, generated by Exterminator-2 reactor code, to the observed If themocouple temperature. It should be noted that throughout Phase I of the test program two separate themocouples were monitored and compared. However, the Doric digital indication was used in determining peak core temperatures because of its faster response and better accuracy as compared to the recorder indication. The temperature recorder was used, though, as a backup indication to the DORIC and was used in two cases to determine peak core temperatures. Pulses #83-1 through #83-15 were performed to establish the Phase I pulse program. Pulse #83-16 was performed as a test to compare the resultant peak core temperature obtained for a different instrumented element position in the core. For this test, the Doric digital temperature instrument was switched to IF #7525, TC #1, located in E-5 (S,W) and the recorder remained. connected to IF #8795, TC #2, locatedinD-6(S,W). The results of this single test were not conclusive as IF #7526 historically displays higher temperature values when compared to other thermocouples under the same conditions. Therefore additional tests will be performed at the Phase I pulsing level to normalize the thermocouples in the two ir strumented fuel elements prior to the initiation of Phase II pulsing. The two instrumented elements, for example, will be interchanged to obtain comparative pulse temperatures for the same core positions. Pulse temperatures will then be obtained for selected high temperature elements by relocating one of the instrumented elements for pulsing at each of these core positions. The tests will pro-vide information for the verification of the power peaking factors j generated by the Exterminator-2 reactor code. A special report will be made to the Reactor Safety Board of the test results. t I l
TABLE I Phasa I Test Data Results T T max max
-T amb Cbserved(Doric) Observed Peak Core Pulse (Recorder) Temp *** Energy (Mw-Sec)
(op ) (o) p u P_ulse # Reactivity ( F) ( F) 83-1 $1.00 70.4 140* 355 665 1.9** 83-2 $1.00 68.4 360 358 672 1.9** 83-3 $1.00 68.4 351 350 654 1.9** 83-4 $1.00 69.3 346 345 642 1.4** 83-5 $1.00 68.9 354 352 659 1.9** 83-6 $1.25 68.8 469 470 892 9.8** 83-7 $1.50 69.0 578 590 1104 16.0** 83-8 $1.50 68.8 577 590 1100 15.3 83-9 $1.50 68.2 578 595 1103 15.5 83-10 $1.50 69.7 577 590 1100 15.5 83-11 $1.75 69.0 665 685 1264 20.1 83-12 $1.75 68.4 667 685 1269 20.1 83-13 $1.75 68.7 662 680 1259 19.2 83-14 $1.85 69.1 700 720 1329 21.4 83-15 $1.85 69.6 701 720 1330 21.3 83-16+ $1.85 70.2 805 720 1360 21.6
*A second meter was in parallel with the doric temperature indicator causing a loading effect and reduced indication (Peak core temperature was determined using observed recorder temperature).
** Corrected value following pulse energy calibration.
*** Peak Core temperatures based on T Observed (Doric).
max IF #7526 TC #1 connected to Doric for pulse #83-16. (Peak core temperature was determined using observed recorder temperature as #7526 TC #1 historically displays a high temperature value). NOTE: IF #8795 TC #1 connected to Doric for pulses #83-1 through 83-15. IF #8795 TC #2 connected to Recorder.
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h l O k 400 - 83 s a Foil activation calibration points !- Iok I 200 l- 5 i Maximum allowable 83 4 o 'gjjj reactivity insertion = $ 2.19 0 O 0.75 1.00 1.25 1.50 1.75 2.00 2.25 PROMPT REACTIVITY INSERTION ($) Figure 2. Peak Core Temperature & Pulse Energy vs. Reactivity for Pulsing Core Vill t - _
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Peak core temperatures and pulse energy were plotted as a function of pulse reactivity, and as shown in Figure 2 a rolloff was observed at pulses greater than $1.50. This effect is due to the very short prompt neutron' lifetime of approximately 16 psec for a FLIP TRIGA core as compared to approximately 40 usec for a Standard TRIGA core. The t'ransient rofwithdrawal system is not fast enough to keep up with the pulse, thus, the selected pulse reactivity is not inserted to its full 7 value. A pcTak core temperature of 1330 F (7210C) corresponding to
- 21.4 N-sec was observed for the $1.85 pulse insertion.
Since Phase II of the program was primarily concerned with pulses yielding peak core temperatures in the range of approximately 1326 F (719 C) to 1526 F (830 C) it was decided at this point to stop and visually inspect and measure the fuel elements of interest. An extrapolation of the data indicates that a reactivity insertion of
$2.19 would generate a peak core temperature of 1526 F (8300C) and a total core energy of 26.0 Mw-sec. It should also be noted that based on this extrapolation a peak core temperature of 1825 UF (996 C) would be attained should the full worth of the transient rod ($2.69) be accidentally inserted. This would result in a peak are temperature below the fuel safety limit of 2100 F (11500C).
It is anticipated that the rolloff will continue for the pulse reactivity insertions of Phase II, thus, the $2.19 maximum extrapolated value from Phase I pulsing is considered to be a conservative limit. Pictures obtained from oscilloscope traces are included in Figures 3 through 7 and demonstrate that a $1.85 pulse produced an approximate
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peak power of 1200 Mw with a pulse width of 10-12 milli-seconds. IV. Results of Fuel Inspection On Thursday, 24 February 1983, Core VIII was partially disassembled and certain predetermined fuel elements were measured and visually in-spected. These elements were in bundles located in core locations C-5, D-4, and E-5. All elements inspected passed the go-no-go test for transverse bend and elongation measurements indicated an insignificant change from the readings obtained in January, 1983. In addition these elements were visually inspected and no severe defects such as surface scratches, puffiness, or bowing were observed. m V. Conclusions It is felt by~the NSC management that based on the data obtained and the favorable results of fuel inspection that the requirements of Phase I have been met. The reproducibility of pulse data was very satisfactory, and the early inspection of the fuel was a conservative measure to detect the onset of fuel damage. As a result of Phase I being terminated with $1.85 pulse reactivity' insertions, it will be necessary to make small revisions to Phase II and III of the initial pulse test program. The first pulse of Phase II will be adjusted downward to a reactivity value which lies halfway between
$1.85 and the maximum extrapolated insertion value of $2.19. Phase III will be changed to establish fuel surveillance based on pulse reactivity insertions equal to or less than the value lying halfway between $1.85 and the maximum allowable reactivity insertion. Upon approval of this report of Phase I test results, approval shall be obtained by the RSB for changes to Phase II and III of the initial pulse test program and to continue with the pulse test program. Phase II and III revisions are attached as Appendix I to this report. It should be noted that Phase II pulsing will be implemented based on experimenter need. Thus, the fuel surveillance requirements of Phase III will be implemented for pul:;ing at the Phase I reactivity insertion level.
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p_ : b i l PULSE #83-5 DATE: 2-21-83 PULSE REACTIVITY: $ l.OO PEAK POWER: 4.9 Mw FWHM:Not Measured S OSCILLOSCOPE CALIBRATION:1.5x10 amp /div DETECTOR CURRENT: lx10 7amp /Mw l Figure 3 t - . - - .. - --
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- 83- 6 DATE: 22183 PULSE REACTIVITY: $ l.25 PEAK POWER:106 Mw FWHM: 0.048 sec OSCILLOSCOPE CALIBRATION: 1.5 x IO-6 amp /div DETECTOR CURRENT: 1xIO-7 amp /Mw Figure 4
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*,,, .k PULSE # 83- 8 DATE: 2-21-83 PULSE REACTIVITY: $ 1.50 PEAK POWER:472 Mw l FWHM: 0.020 sec OSCILLOSCOPE CALIBRATION:lxlO'5 amp /div DETECTOR CURRENT IxlO'7 amp /Mw Figure 5 l __
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I:3 ,{ J. 'll PULSE #83-14 DATE:2 21-83 PULSE REACTIVITY: $ 1.85 PEAK POWER:1216 Mw l FWHM: 0.010 sec OSCILLOSCOPE CALIBRATION:2xIO-samp/div DETECTOR CURRENT: IxIO-7 amp /Mw U t s 1 Figure 7
s . APPENDIX I Revision of Phase II and Phase III of the Full FLIP Pulse Test Program
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fievision of Phase II of the Full FLIP Pulse Test Program Phase I pulsing was terminated at a reactivity insertion of $1.85 which resulted in a peak core temperature of approximately 1330 F (7210 C). Thus, in this phase the pulse reactivity insertion to produce peak core temperatures of approximately (13300 F (721 C) < T core < 1526 F (830 C) will be determined.
- Fuel element inspections are included in this phase of the pulse program.
- 1. From the extrapolated results of Phase I select the extrapolated value of the pulse reactivity insertion predicted to lie half-way between $1.85 and the maximum allowable pulse insertion (i.e., the pulse required to reach a maximum core temperature of 1526 F) (8300C).
- 2. Pulse the reactor at the value obtained above and immediately inspect visually the fuel elements of interest (see Section V).
- 3. After reassembly of the core select a pulse reactivity insertion of near maximum allowable value.
- 4. Pulse the reactor at the near maximum allowable pulse insertion and immediately inspect visually the fuel elements of interest (see Section V).
(If the pulse reactivity insertion in Item 1 is considered to be a near maximum pulse then proceed to Item 5 following inspection of the fuel).
- 5. Execute five (5) near maximum pulses and compare observed temperature and energy for reproducibility.
- 6. Halt pulsing and immediately inspect fuel by visual means and direct measurement of elongation and bowing. In addition to the fuel elements previously inspected during the pulse test program, the elements in the instrumented and transient rod bundles will be inspected.
- 7. Prepare a report of the near maximum pulsing results for presentation to the RSB for review and approval to proceed to Phase III of the pulse test program.
- 8. Provide a copy of the results of Phase II to the USNRC (Washington and Region IV) following review and approval by the RSB.
Note: The reactor may be pulsed during the review and approval period of Phase II assuming no damage was detected. Pulse insertion values will be limited to one-half the value between
$1.85 and maximum allowable insertion.
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Revision of Phase Ill of the Full FLIP Pulse Test Program This phase of the prv" am represents continued surveillance of fuel for pulse damage should it occur. This phase is designed to complement the proposed fuel surveillance requirements of the Technical Specifications for renewal of License R-83. The new Technical Specification will require an annual fuel inspection program. This phase will require the following fuel inspections:
- 1. The elements of interest as described in Section V will be inspected as follows:
(a) Visual inspection following each 25 pulses of reactivity insertion value equal to or less than the value lying half-way between $1.85 and the maximum allowable reactivity insertion, and (b) Visual and measured inspection following each 15 pulses of reactivity greater than the half-way value described in (a) above. (c) Inspection annually of fuel in accordance with Technical Specification requirements.
; 2. This inspection program will continue as follows:
(a) Until the total number of pulses of 1(a) has reached 75, or (b) Until the total number of pulses of 1(b) has reached 45, whichever comes first. (Note that this will extend beyong the total equivalent pulsing of Core III-A). (c) Following completion of the requirements of 2(a,b) the elements in the instrumented and transient rod bundles will be inspected by visual and measurement methods. (d) Annual inspection of fuel will be performed in accordance with Technical Specification requirements. l Note: The fuel surveillance requirements of 1(a) and 2(a) above shall be implemented following completion of Phase I of the pulse test program and the requirements of 1(b) and 2(b) shall be implemented upon completion of Phase II. I _ - , ~ _ - - - - -
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