ML18037A454
| ML18037A454 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/15/1993 |
| From: | Zeringue O TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M84395, NUDOCS 9309210260 | |
| Download: ML18037A454 (10) | |
Text
ACCELERATE DOCUMEN'1" DISTRI TION SYSTEM REGULAT INFORMATION DISTRIBUTIO STEM (RIDS)
ACCESSION NBR:9309210260 DOC.DATE: 93/09/15 NOTARIZED: NO DOCKET N
FACIL::50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH.NAME AUTHOR AFFILIATION, ZERINGUE,O.J.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards suppl info.requested by NRC re TS Table 3.2.C,to revise flow-biased RBM upscale setpoint resulting from reanalysis of limiting control rod withdrawal error operational transient.
DISTRIBUTION CODE:
D030D COPIES RECEIVED: LTR i
ENCL g SIZE:
TITLE: TVA Facilities Routine Correspondence NOTES:
RECIPIENT ID CODE/NAME COPIES LTTR ENCL RECIPIENT ID CODE/NAME COPIES LTTR ENCL INTERNAL: ACRS OC.
DCB EG F
EXTERNAL: NRC PDR Ol 6
6 1
0 1
1 1
1 NRR/DSSA OGC/HDS3 RES/DE/SSEB/SES NSIC 1
1 1
0 1
1 1
1 S
NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACI'fHEDOCUMEN'I CON'I'ROI. DIISK, ROOM Pl-37 (EXT. 504-20(i5) TO FLIMINATFYOUR NAME FROM DIS'fili!II)'I'ION LISTS FOR DOCUMEN'I'S YOU DON'T NEED!
D TOTAL NUMBER OF COPIES REQUIRED:
L'TTR 13 ENCL 11
41 4'L r
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Tennessee Vatley Autbority. Post Office Box 2000, Decatur. Alabama 35609-2000 O. J.
Ike" Zeringue Vice President, Browns Ferry Nuclear Pfant SEP l5 1993 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter Of Tennessee Valley Authority Docket Nos.
50-260 BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 TECHNICAL SPECIFICATION (TS)
CHANGE TS-303 SUPPLEMENTAL INFORMATION (NRC TAC NO ~ M84395)
Reference:
Letter from TVA to NRC dated October 5,
No.
303 Flow-Biased Rod Block Monitor (RBM) Upscale Setpoint Change In the referenced letter, TVA forwarded to NRC a TS change to revise the flow-biased RBM upscale setpoint (TS Table 3.2.C) as a result of a reanalysis of the limiting control rod withdrawal error operational transient.
TVA also proposed to revise TS 3.3.B.5/4.3.B.5 to express the RBM subsystem limiting condition for operation and surveillance requirement in terms of thermal parameter limits supported by this reanalysis.
In addition, the TS change proposed to add a new definition, Core Maximum Fraction of Critical Power, and adopt the Boiling Water Reactor Standard Technical Specification definition of Limiting Control Rod Pattern.
During NRC's review of this TS change, NRC has requested that TVA provide supplemental information.
Accordingly, the enclosure to this letter provides the supplemental information requested by NRC.
sooo260 qgo'st % 5 PDR, ADQCQC0 pDR P
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U.S. Nuclear Regulatory Commission Page 2
SEP %5 1993 If you have any questions, please call Pedro Salas at (205) 729-2636.
Since e
O.
. Zering e Enclosure cc (Enclosure):
Mr. R. V. Crlenjak, Project Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street,,
NW,. Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns. Ferry Nuclear Plant Route 12,,
Box 637
- Athens, Alabama 35611 Mr. Thierry M. Ross, Project Manager U.S. Nuclear Regulatory.'.Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
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S/
ENCLOSURE BROWNS FERRY NUCLEAR PLANT (BFN)
PROPOSED TECHNICAL SPECIFICATION (TS)
CHANGE TS-303 - ROD BLOCK MONITOR (RBM)
UPSCALE SETPOINT SUPPLEMENTAL INFORMATION NRC uestion 1
"When thermal margin is greater than five percent, is one operable RBM channel sufficient to prevent violation of fuel safety limits?"
TVA Res onse The analysis of the limiting rod withdrawal error (RWE) event performed for the current fuel cycle demonstrates that this event does not cause violation of the fuel safety limit when one RBM channel is inoperable and the initial core maximum fraction of critical power (CMFCP) and core maximum fraction of limiting power density (CMFLPD) are less than or equal to 0.95 (i.e., the thermal margin is greater than five percent).
The analysis also demonstrates that the fuel safety limit is not violated when the CMFCP and CMFLPD are equal to 1.0 (i.e., the thermal margin is zero) and both RBM channels are operable.
This analysis will be performed for subsequent fuel cycles.
NRC uestion 2
"How are thermal limits determined if the computer is out of service?"
TVA Res onse BFN Technical Instruction (TI) O-TI-46, "3D Monicore Manual Monitor," is utilized to perform a backup thermal limits calculation when the integrated computer system is unavailable.
This TI provides
~a means to manually collect input data along with a procedure to perform a thermal limits calculation on the off-line backup computer.
NRC uestion 3
1 "TS-303 provides justification for revising the RBM upscale setpoint for Unit 2, Cycle; 6. If the change is intended for subsequent fuel cycles, provide additional information to confirm that the analysis is bounded.,",,
TVA Res onse The limiting RWE'vent is analyzed for each reload cycle to determine the allowable fue'l operating limits.
The TS allowable setpoints and operabil'ity requirements provide input to the
~l
~y'
cycle-specific analyses.
Examples of the analyses for Unit 2, Cycle 6 were provided as part of TS-303.
Unit 2, Cycle 7
analyses are documented in General Electric's report 23A7190, "Supplemental Reload Licensing Report For Browns Ferry Nuclear Plant Unit 2 Reload 6 Cycle 7," Revision 1, April 1993.
Similar analyses will be a standard',part of each reload analysis.
The basic analysis process is described in General Electric's document NEDE-24011-P-A (GESTAR-II), "General Electric Standard Application for Reactor Fuel."
NRC uestion 4
"The definition of Core Maximum Fraction of Critical Power discusses the
'CPR operating l'imit defined in Technical Specifications.
, Is the.,CPR,operating limit still in the TS, or was it removed by TS-309,- Core Operating Limits Report, approved by amendment numbers 197.,
- 214, and 170 for Units 1, 2, and 3
respectively, dated May 20,, 1993?"
TVA Res onse The CPR operating limi.t was in the TS at the time this TS change was submitted.
However, it was subsequently removed and relocated to the Core 'Operating Limits Report by amendment number 197/214/170 (TS-309).
As a result, the definition of Core Maximum Fraction of Critical Power (Definition 1.U.5) should be revised as follows:
"5.
Core Maximum Fraction of Critical Power 'MFCP Core Maximum Fraction of Critical Power is the maximum value of the ratio of the flow-corrected CPR operating limit found in the Core Operating Limits Report divided by the actual CPR for all fuel assemblies in the core."
.Additionally, since amendments 197/214/170 (TS-309) added a new definition to the TS, the proposed definition of Limiting Control Rod Pattern in TS-303 should be renumbered from 1.00 to 1.PP.
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