View source for B11750, Forwards Rev 1 to NUSCO-137, Millstone Unit 3 Boron Dilution Analysis for Failures in Chemical & Vol Control Sys. Rev Documents Compliance W/Min Operator Action Times for Boron Dilution Events W/O New Data

{{Adams
| number = ML20137Z520
| issue date = 10/01/1985
| title = Forwards Rev 1 to NUSCO-137, Millstone Unit 3 Boron Dilution Analysis for Failures in Chemical & Vol Control Sys. Rev Documents Compliance W/Min Operator Action Times for Boron Dilution Events W/O New Data
| author name = Opeka J
| author affiliation = NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
| addressee name = Youngblood B
| addressee affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| docket = 05000423
| license number = 
| contact person = 
| document report number = B11750, NUDOCS 8510080265
| package number = ML20137Z527
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 2
}}

=Text=
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(203) 66s-s000 1
October 1,1985 Docket No. 50-423 B11750 Director of Nuclear Reactor Regulation Mr. B. 3. Youngblood, Chief Licensing Branch No.1 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C. 20555

==References:==
(1)     W. G. Counsil letter to B. 3. Youngblood, Transmittal of Boron Dilution Analysis for Failures in the Chemical and Volume Control System, dated February 10,1984.
Gentlemen:
Millstone Nuclear Power Station, Unit No. 3 Revision to Millstone Unit 3 Boron Dilution Analysis Enclosed is Revision I to NUSCO-137, " Millstone Unit 3 Boron Dilution Analysis for Failures in the Chemical and Volume Control System" submitted in reference (1).
Revision I was performed for this report in order to account for more recent design details and nuclear analyses pertaining to selected aspects of this report, specifically:
: 1.        Boron concentrations as a function of temperature required for specified shutdown margins.
: 2.        Dilution flow rates based on current design documents listing operating system pressures for pertinent piping systems.
The analysis shows that Millstone Unit 3 can be operated with shutdown margins of 1.6% in Modes 3,4, and 5 (vs. the 2% assumed in the original analysis) without violating the minimum operator action times specified in Section 15.4.6 of the Standard Review Plan (SRP). Additionally, Mode 6 operations with a critical boron concentration of 980 ppm also comply with the minimum operator action time based on a dilution flow rate of 110 gpm through V-305, emergency boration line flush valve, identified in the original analysis as the source of the maximum dilution flow rate. The new flow rate through V-305 is based or more detailed engineering data than was available at the time of the original analysis.
This revision documents compliance with the minimum operator action times for boron dilution events at Millstone Unit 3 given new data not available at the time of the original analysis. The risk analysis portion of the analysis is not                                   00\
8510080265 851001 PDR      ADOCK 05000423
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being modified at this time since the increased time available for operator action considered in the revision will result in lower probabilistic values for the likelihood of a boron dilution event occurring and proceeding to a loss of shutdown margin.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY et. al.
BY NORTHEAST NUCLEAR ENERGY COMPANY Their Agent
: 3. F. OpeW
                                                    % R CM.                       U Senior Vice President STATE OF CONNECTICUT )
                                   ) ss. Berlin COUNTY OF HARTFORD           )
Then personally appeared before me 3. F. Opeka, who being duly sworn, did state that he is Senior Vice President of Northeast Nuclear Energy Company, an Applicant herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Applicants herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.
A M i r*                                        MW Sotary Pupg My Confmission Expires Wrch 31,1988 Y                                          _               . _     _ _ _ _ _ - _ _ _ _ _ _ _    _}}