ML20084S765
| ML20084S765 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/02/1995 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9506120190 | |
| Download: ML20084S765 (7) | |
Text
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Station Support Department i
.g PECO ENERGY 72f '!!3'": Le,,
965 Chesterbrook Boulevard Wayne. PA 19087-5691 l
June 2,1995 Docket No. 50-277 50-278 Ucense No. DPR-44 GP.9-56 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555
SUBJECT:
Peach Bottom Atomic Power Station, Units 2 and 3 Facility Operating Ucense Change Request 94-07, Supplement 1
REFERENCE:
Letter from G. A. Hunger, Jr. (PECO Energy) to NRC dated January 13,199.5
Dear Sir:
In the referenced letter, PECO Energy Company submitted Ucense Change Request (LCR) 94-07, in accordance with 10 CFR 50.90, requesting changes to Appendix A of the Peach Bottom Atomic Power Station (PBAPS) Facility Operating Ucenses.
The proposed changes concem a revision to the frequency of calibratic n for the Local Power Range Monitor (LPRM) signals from every 6 weeks to every 2000 Megawatt Days per Standard Ton (MWD /ST).
During a May 16,1995 meeting, PECO Energy and GE Nuclear Energy provided the NRC staff with supplementalinformation regarding LCR 94-07. At the conclusion of the meeting, the staff requested that PECO Energy formally submit the information provided. Accordingly, this letter supplements our earlier submittal by providing the requested information (see Attachment). This information was prepared by GE Nuclear in support of the May 16,1995 meeting.
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i June 2,1995 Page 2 if you have any questions concerning this submittal, please contact us.
l Sincerely,-
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G. A. Hunger, Jr.,
~ Director - Licensing
Enclosures:
Affidavit, Attachment cc:
T. T. Martin, Administrator, Region I, USNRC g
W. L Schmidt, Senior Resident inspector, PBAPS, USNRC R. R. Janati, Commonwealth of Pennsylvania t
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. COMMONWEALTH OF PENNSYLVANIA l
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COUNTY OF CHESTER W. H. Smith, Ill, being first duly sworn, deposes and says:
That he is Vice President of PECO Energy Company; the applicant herein; that he has read the attached License Change Request (LCR 94-07, Supplement 1) for changes to the Peach Bottom Facility Operating Ucense DPR-44, and knows the contents thereof; and that the statements and matters set forth therein are true and i
correct to the best of his knowledge, information and belief.
t Vice Presidenf i
Subscribed and sworn to before me this day i
of b W 1995.
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ATTACHMENT l
Supplemental information to LCR 94-07 for
.q Peach Bottom Atomic Power Station, Units 2 and 3 -
"LPRM Signal Calibration Frequency"
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,t Peach Bottom 2 & 3 TechnicalSpecification Change LPRM Calibration Change to 2000 MWDIST SupplementalInformation l
Procedure for Determining Nodal RMS Uncertainty Start fiom cases where power distribution was determined immediately after TIPS were run.
Power distribution is based on the TIP flux data rather than LPRM flux data. Five cases were utilized:
DATE-6 EXPOSURE (OR MWDff)i
'M ACoW J Cycles iSequencey Changes iEFPH*4 4
07-23-91 11545.7 1016.4 A2 08-03-91 11783.5 1254.2 A2 237.8 265 09-02-91 12422.9 1893.6 A2 877.2 976 10-13-91**
2768 A2=>Al 10-18-91 13413.2 2883.9 Al 1867.5 2078 11-25-91 14233.2 3707.9 Al 2687.5 2991
- Effective FullPowerIlours
" Information only LPRM calibrations were performed prior to the cases of 9-02-91,10 46-91 and 11-25-91. The calibration curn:nt data were obtained fmm Hatch 2 and LPRM reading consistency for the LPRM monitoring cases was maintained by nulling out the LPRM amplifier changes.
Calibration currents are those currents that the LPRM detectors generate when the meter should read a fixed valued (typically 100 meter units). As an individual LPRM looses sensitivity, the calibration current decreases. This decrease is compensated in calculations based on an expected rate of decrease of the detector sensitivity. The decrease also is corrected physically by adjusting individual LPRM gain amplifiers to yield the conect LPRM meter readings.
For this analysis, the effect of the physical calibration of the LPRM gain amplifiers were reversed relative to the 7-23-91 LPRM readings for input to downstream LPRM monitoring cases as follows:
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" Peach Bottone 20 3 Technical Specification Change l
LPRM Calibration Change to 2000 MWD /ST e ~ l SupplesmentalInforniaten i
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PCLPRM = PCLPRM
- CALCUR/CALCUR(7-23) l o
where: PCLPRM
' LPRM Reading Input
=
l PCLPRM from Adaptive f
-PCLPRM
=
o Case l
CALCUR(7-23)
Chamber Calibration current
=
on 7-23 CALCUR Current Chamber Calibration
=
current The site cases after TIPS wem nrun using steady state xenon and the monitoring programs' calculated decay of the LPRM sensitivity. These cases were used as the basis for determining the additional uncertainty caused by running in the LPRM mode for up to 2991 EFPH without running TIPS and calibrating the LPRMs.
Starting fmm the 7-23-91 case after TIP case, LPRM monitoring cases were run
.f as follows:
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1.
Run an LPRM case burning from 7-23-91 to 8-03-91 using the live plant
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data from the 8-03-91 case. No PCLPRM cormction was required.
2.
Run an LPRM case restarting from the above 8-03-91 case burning to the 9-02-91 case and using the live data from the 9-02-91 case. Correct the PCLPRM inputs as discussed earlier.
3.
Repeat this process for the 10-18-91 and Il-25-91 cases.
l Compute the standard deviations of the nodal powers comparing the LPRM and corresponding TIP case results.
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Peach Bottom 2 & 3 Tech ical Specificction Chrge LPRM Calibration Change to 2000 MWD /ST Suppicmentalinformation Nodal Power RMS versus Exposure 3
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42 4.3 4-3.7 3.5 -
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2.1 2-1.5 -
1-05-0-
n 265 976 2078 2991 Change in EFPH Combining the 4.2% additional uncenainty with the other components contributing to nodal uncertainty (Power calculations, LPRM available, TIP available for calibration, use of thermal TIP), the total nodal uncertainty is well bellow the value assumed in the GETAB Analysis. For gamma TIP plants, the total uncertainty is even less.
Applicability to Other Cores Additional exposum of LPRM detectors - and associated change in LPRM readings - create penurbations in nodal power calculations (an additional uncertainty) about a base calculation.
That base calculation which accounts for different core loadings has its own associated uncenainty that is uneffected by the proposed change in LPRM calibration frequency. As similar LPRMs at diffemnt sites behave in the same manner with additional flux reganiless of the source of that flux, the perturbations and additional uncenainty will be similar.
'Ihis change is dependent on uncenainties in the nodal power and additional LPRM exposure being based upon the same nuclear methods. Also, LPRM detectors are assumed to behave in a predictable manner with exposure.
i The study's use of a conventional com is bounding over control cell core (CCC) configuration as sequence exchanges in conventional cores would introduce larger flux uncertainty than deep-shallow swaps in contml rod positions in CCC.
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