ML20137Z541

Rev 1 to Millstone Unit 3 Boron Dilution Analysis for Failures in Chemical & Vol Control Sys

ML20137Z541
Person / Time
Site:	Millstone
Issue date:	10/01/1985
From:	NORTHEAST NUCLEAR ENERGY CO.
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Shared Package
ML20137Z527	List: 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 ML20137Z541
References
NUSCO-137, NUSCO-137-R01, NUSCO-137-R1, NUDOCS 8510080270
Download: ML20137Z541 (5)

Text

7.0 References

1. Westinghouse internal memo, R. Mark to C. Sterrett, Fluid Systems FSAR input data for NEU, August 11, 1977, N4SA-New-506, Westinghouse Proprietary Class 2 (re: RCS volumes, Milsitone Unit 3).

2. NE-83-R-574, Millstone Unit 3 Shutdown Boron Concentrations for use in Boron Dilution Analysis, memo from J. A. Camp to R. L. Beveridge.

3. NUREG/CR-1278, Handbook of Human Reliability Analysis with Emphasis on Nuclear Power Plant Applications - Draf t Report for Interim Use and Comment.

4. Millstone Nuclear Power Station, Operations Procedures OP3208 (Draf t A),

OP3304A (Draf t B), and OP3304C (Draf t C).

5. NUREG/CR-3010, Post Event Human Decision Errors: Operator Action Tree / Time Reliability Correlation.

6. Personal communication from R. H. Langer to R. L. Beveridge.

7. Millstone Unit 3 Probabilistic Safety Study, August 1983.

8. Stone & Webster Engineering Corporation Engineering Calculation Note 12179-816T (R), " Millstone 3 Residual Heat Removal System Piping and Equipment Volume."

9. Personal communication from J. Mallick (SWEC) to R. Beveridge (NUSCO).

10. Northeast Utilities Service Company Millstone Nuclear Power Station Unit No. 3 Precautions, Limitations and Setpoints for Nuclear Steam Supply Systems, S. O. NEU-490, November 1982.

11. NE-85-R-253, Millstone Unit 3 Boron Dilution Analysis, memo from J. A. l Camp to R. L. Beveridge, May 23,1985.

8510080270 851001 NUSCO-137 PDR ADOCK 05000423 Revision 1 A PDR October 1,1985 L A

APPENDIX B: Boron Dilution Analysis Table B.1 shows the input data for the boron dilution model described in Appendix A, including the source of each parameter. Table B.2 displays the results of the calculations in terms of time to alarm (td) and time to loss of shutdown margin (tc)-

The boron concentration rations were taken from Reference 2 and are based on boron worth at beginning of life, cold plant conditiens to assure conservative results.

Boron concentrations used in the analysis are the result of several iterations performed to determine which concentrations would yield time differentials consistent with the minimum allowable times for operator action in boron dilution events from Section 15.4.6 of NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants. This procedure yielded best estimate values for Millstone 3 shutdown margins and was required since the safety analyses that will determine the initial boron concentrations have not been performed as of this writing. Shutdown margins used in this analysis are as follows:

o Modes 3,4 - 1.6 percent o Mode 5 - 1.6 percent o Mode 6 -initial boron concentration from FSAR Dilution flowrates are based on engineered features in the respective systems:

o Unborated flushing flow to the chemical additional tank is limited to 2 gpm by an orifice.

o Primary gr .de water is supplied to various components at 50 gpm.

o Normal charging flow is set at 55 gpm through the charging flow control valve and 20 gpm via the reactor coolant pump seals for a total flow of 75 gpm.

o The emergency boration line flush valve, V-305, was calculated to have a mixumum possible actual flow of 110 gpm. l o The Failed Fuel Monitor flush valve, AOV 64, was calculated to have a maximum possible actual fow of 27 gpm.

NUSCO-137 Revision 1 October 1,1985

o TABLE B.1 Input Data For Appendix A Calculations Mode Parameter Value Source 3,4 RCS Volume 76,072 Reference I fo 0.2

• 6 Co 1079 ppm Reference 11 Cc 940 ppm Reference 11 5 RCS Volume 79,183 gal.(2) Reference 1,8 l Go 0.2 6

Co 1116 ppm Reference 11 Cc 980 ppm Reference 11 6 RCS Volume 28,843 gal.(3) Reference I 0.2 l_o Co 2000 ppm MNPS-3 FSAR Cc 980 ppm Reference 11 l

+ Based on High Flux at Shutdown Alarm setpoint of SX background.

(1) 10,170 ft3 (RCS piping volume less pressurizer and surge line)

(2). 10,586 ft3 (includes 50 percent of RHR System Volume)

(3) 3,856 ft3 (to reactor vessel flange; loops isolated)

NUSCO-137 Revision 1 October 1,1985

TABLE C.2 Human Error Probabilities vs. d t Case a t (min.)~

Mode Flow Rate jcgg H.E.P.*.

3/4 110 20.2 3.5 x 10-3 l 75 29.8 1.4 x 10-3 50 44.6 6.0 x 10-4 27 202.3 1.0 x 10-4 2 1117 1.0 x 10-4 5 110 19.7 3.5 x 10-3 75 31.0 1.5 x 10-3 50 46.5 5.0 x 10-4 27 210.5 1.0 x 10-4 2 1162 1.0 x 10-4 6 110 49.6 4.5 x 10-4 l 75 66.1 3.0 x 10-4 50 99.3 1.0 x 10-4 27 411.4 1.0 x 10-4 2 2431 1.0 x 10-4

• Reference 5 NUSCO-137 Revision 1 October 1,1985

i, 8 v

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I P

ItEFUEL COLD S/D liOT STBY-110T S/D til tc td tc td tc 110 117.5 187.0 93.5

73. P. 75.2 95.4 75 188.9 255.0 115.6 146.6 111.1 140.9 If 50 283.3 382.6 173.4 219.0 166.7 211.3 M

=

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u. 27 297.0 708.4 196.6 407.1 189.0 391.3 5

y 2 7083 9564 4336 5498 4166 5283 '

d TIME (Hin.)

O tO C Table B.2 E1E Ei?

4

!!Oll0N DILUTION ANALYSIS RESULTS-BASE CASE '

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