ML20214W621
| ML20214W621 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 12/03/1986 |
| From: | Mckenna E Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8612100330 | |
| Download: ML20214W621 (27) | |
Text
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DEC 0 31996 Docket No.'50-029 LICENSEE:
Yankee Atomic Electric Company (YAEC)
FACILITY:
Yankee Nuclear Power Station
SUBJECT:
MEETING
SUMMARY
- DECEMBER 2, 1986 On December 2, 1986, members of the NRC staff met with representatives of YAEC to discuss incore detectors at the Yankee plant. A list of attendees is provided in Enclosure 1.
The presentation material used by the licensee during the meeting is provided in Enclosure 2.
The purpose of the meeting was to discuss YAEC's plans to install fixed incore detectors for power distribution measurements.
The existing incore detection system at Yankee has moveable detectors inside of tubes. However, failures of the tubes have occurred several times in the past. At present, 13 of the original 22 paths are available.
Rather than attempting additional repairs to this system, the licensee plans to install fixed detectors in 8 of the unavailable locations during the 1987 refueling outage (presently scheduled for May 1987).
Each of the eight strings of detectors will contain 5 Rhodium detectors.
During the startup and during the subsequent six months of operation, data from the fixed detectors will be collected for cross-correlation with data from the moveable detector maps to develop appropriate measurement uncertainty factors. With favorable results, a submittal would then be made to the NRC with a proposal to use the fixed incore detectors for power distribution mapping in place of the moveables.
For the initial portion of Cycle 19, including the startup, the moveable detector system will be used for these measurements. The Technical Specifications (TS) require that a minimum of 12 detectors be operable, with two per quadrant. As noted above,13 detectors are presently available.
Because of concerns for additional failures, a TS change was recently issued (December 1, 1986) which permits the minimum number of detectors to be 9, with 1 per quadrant, for the balance of Cycle 18.
At startup from Cycle 19 though, the TS requirement would revert to 12.
However, until the fixed detector system has been installed, the data analyzed, and the uncertainty factors quantified, the moveable detector system will still be needed for power distribution mapping. The licensee would therefore like to extend the reduced number of detector TS for Cycle 19 as well, h2100330861203 ADOCK 05000029 p
. The staff acknowledged the licensee's position but noted that the staff generally desires to have a larger number of detectors available particularly for startup to help detect any misloading or anomaly in the core.
The licensee noted several factors that would reduce the likelihood of mis-loading or that would aid in detection of problems.
For instance, there are only two types of assemblies which are shaped differently and thus cannot be misloaded. Also, fuel is only used in two cycles with the new fuel placed on the outside areas of the core. The fuel to be used in the upcoming cycle is similar to that used on the last few cycles. Further, Yankee performs a large number of startup tests, and in past cycles has achieved excellent consistency and accuracy of predictions versus measurements.
The licensee will submit proposed TS changes for Cycle 19, including a discussion of these factors to support their request, by the end of January, 1987. The staff will evaluate this request considering the status of the moveable and fixed detectors at the time of plant startup. As noted above, following installation of the fixed incores and development of the data reduction / measurement uncertainty factors, proposed TS changes for use of the fixed incores in place of the moveable detectors will be provided late in 1987.
N Eileen M. McKenna, Project Manager Project Directorate #1 Division of PWR Licensing-A
Enclosures:
As Stated cc's: See Next Page
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Office:
PMfPAJf1 PD/ PAD #1 2
Surname:
EMcKenna/ g Glear [7 /07 Date:
12/ 3 /86 12/ 3 /86
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DEC 0 31988 DistributiNnCopies:
'DeciEENNI5iMif93' NRC PDR Local PDR PAD #1 r/f PADil s/f GLear EMcKenna OGC-Bethesda EJordan BGrimes ACRS (10).
MChatterton WBrooks MDunenfeld RLobel-(cc: Licensee and Plant Service List) e I:
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Mr. George Papanic, Jr.
Yankee Atomic Electric Company Yankee Nuclear Power Station cc:
- Mr. James E. Tribble, President Yankee Atomic Electric Ccepany 1671 Worcester Road Framingham, Massachusetts 01701 Tbcmas Dignan, Esquire Ropes and Gray 225 Franklir. Street Scston, Massachusetts 02110 Mr. N. N. St. Laurent Plant Superintencent Yankee Atomic Electric Company Star Route
- Rowe, Massachusetts 01367 Chairman Board cf Selectmen Tcwn of Rowe Powe, Massachusetts 01367 Resident Inspector Yankee Nuclear Power Station c/o U.S. NRC Post Office Box 28 Monroe Bridge, Massachusetts 01350 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Robert M. Hallisey, Director Radiation Control Program Massachusetts Department of Public Pealth 150 Tremont Street, 7th Floor Boston, Massachusetts 02111 e
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ENCLOSUPE 1 I
YAEC/NRC MEETIh6 DECEMEER 2, 198f NAME AFFILIATICN
.Eileeri McKenna NRC R. J. Cacciapouti YAEC
~K. J. Morrissey Y/EC K. R. Hurlburt YAEC G. Papanic Jr.
YAEC Margaret Chatterton hRC George lear NRC Walter L. Brooks NRC Marvin Dunenfeld NRC Richard Lcbel NRC.
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4 YANKEE FIXEO DETECTOR SYSTE\\A APPLICATION STRAGETY o OBTAIN AXIAL SHAPE VIA SPLINE FIT C EXPAND TO EQUIVALENT MOVEABLE TRACE DATA o SUPERIMPOSE GRID DIPS l
0 PROCESS DATA VIA INCORE O DETERMINE UNCERTAINITY e NRC SUBMITTAL APPROX 6 MO AFTER STARTUP i
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D-YANKEE INCORE DETECTOR SYSTEM CURRENT TECHN CAL SPECIFICATIONS e CURRENT OPERABILITY SPECIFICATION 212 THIMBLES OPERABLE a 2 THIMBLES PER QUADRANT o CURRENT UNCERTAINTIES 5.0 % 317 6.8 % 212 <17 O CYCLE 18 EXCEPTION O OPERABILITY 2 9 THIMBLES OPERABLE a 1 THIMBLE PER QUADRANT 4
l O UNCERTAINITY 5.0 % e17 6.8 % z12 < 17 8.0 % = 9 < 12
1 YAN(EE INCORE DETECTOR SYSTEM INTERIM TECHN CAL SPECIFICATIONS c COVER CYCLES 18 AND 19 c UNCERTAINITY APPLIED 5.0 % 217 6.8 % 212 < 17 8.0 % a 9 < 12 GREASONS SIMILAR LOADING PATTERNS SIMILAR POWER DISTRIBUTIONS ODD CYCLES BOUNDED BY EVEN CYCLES ACCURATE PREDICTIONS TRANSITION TO FIXED DETECTORS
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l COMPARISON OF MEASURED AND PREDICTED SIGNALS INCORE RUN YR-16-013 599.9 MWT. GROUP C AT 85.0 INCHES 1172. MWD /MTU 0.605 0.614
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AVERAGE ABSOLUTE DIFFERENCE BETWEEN MEASURED AND PREDICTED 1.265 PERCENT
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COMPARISON OF MEASURED AND PREDICTED SIGNALS INCORE RUN YR-17-013 1656. MWD /MTU 599.3 MWT. GROUP C AT 84.9 INCHES 0.686 0.687 0.0 0.981 O.987
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1.136 0.0 1.12 0 1.0 17 1.115 1.004 0.5 1.3 1.023 1.023 0.0 0.667 0.996 WEASURED SIGNAL 0.000 1.012 PREDICTED SIGNAL
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-1.6 PERCENT DIFFERENCE AVERAGE ABSOLUTE DIFFERENCE BETWEEN MEASURED AND PREDICTED 0.788 PERCENT RMS ERROR 1.19 5
COMPARISON OF MEAS'JRED AND PREDICTED SIGNALS INCORE RUN YR-18-010 600.0 MWT. GROUP C AT 83.625 INCHES T738. MWDAETU 0.670 0.690
-2.9 1.099 1.142
-3.7 1.051 0.983 1.050 0.979 0.1 0.3 0.989 1.104 0.981 1.078 0.8 2.4 1.070 1.069 1.038 1.054 3.0 1.5 1.057 1.032 2.4 1.106 0.989 1.081 0.9 87 13 03 1.054 1.060
-0.5 0.651 1.11 0 WEASURED SIGNAL 0.672 1.157 PREDICTED SIGNAL
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-4.0 PERCENT DIFTERENCE AVERAGE ABSOLUTE DIFFERENCE BETWEEN MEASURED AND PREDICTED 1.945 PERCENT RMS ERROR 2.352
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c APPROXIMATELY 25 % POWER e APPROXIMATELY 60 % POWER o APPROXIMATELY 75 % POWER c APPROXIMATELY 90 % POWER i
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