ML19329B654
| ML19329B654 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 01/05/1977 |
| From: | Bunch D Office of Nuclear Reactor Regulation |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8002050763 | |
| Download: ML19329B654 (8) | |
Text
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Distribution
' Central File DSE Reading
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NRR Reading C. Ferrell AAB Reading L. Soffer AAB File R. Vollmer L. Engle D.' Bunch.
Docket Jo. 50-346 JAh 5 1977 MEl!DRAUDUM FOR:
J. F. Stolz, Chief, Light Water Reactors Branch lio.1 DP!!
FRON:
D. F. Bunch, Chief, Accident Analysis Branch, DSE
SUBJECT:
REVISED DAVlS BESSE UdIT NO 1 DBA DOSES PLANT NAME: Davis Bessa Unit No. 1 LICENSI;!G STAGL: OL DOCKET NU:3ER: 50-346 MILESIONE NLYJdER: 27-31 RESPOMSIBLE BPM CH: LWR #1; L. Engle, LPM REQUESTED COMPLETION DATE: N/A REVIEW STATUS: Raview Continuing At.tached are the revised Davis Besse Unit No. 1 design basis accident doses which are based on the two years of meteorological data provided by the applicant. Havised X/Q values were provided by ILMB on Decet:bcr 13, 1976. The 0-2 hour site boundary X/Q value remains unchanged while the 0-30 day LPZ values are reduced by roughly a factor of.05 fron those used in our previcus analysis. Those LOCA doses are based on the 302 second positive pressuro period as provided by the LPM and D. Piciett of CS3 on January 3, 1977.
If the positive pressure period was further increased to 840 seconds, the site boundary thyroid dosas would be about a ren higher.
This evaluatica was provided by C. Ferrell, Sita Analyst, Section 3, Accident Analysis Branch.
/
D... Dunca, Chief Accident Analysis Branch Division of Site Safety and Environmental Analysie
Enclosure:
acvised Davis Becsc Unit.io. 1 D5A Loses ri:
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_1h77 Form ABC 31s iRev.M3) AICM 0240 W u. s. oovanument eniaevine orries ser..sae.see 8002050763
TABLE 15.1 ASSUMPTIONS USED TO ESTIMATE RADIOLOGICAL CONSEQUENCES CUE TO A POSTULATED LOSS OF COOLANT ACCIDENT AT DAVIS BESSE UNIT 1 Power level, megawatts thennal 2772 3
Operating time, years Primary Containment Leak Rate, percent per day 0.5 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 0.25 greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Fraction of Core Inventory Available for Leakage from Containment:
Noble Gases 100 percent Iodine 25 percent Bypass Leakage Fraction, percent of Primary Containment Leak Rate 100.
0-802.sec.
3.
802'sec, to 30 days 6
Primary Containment Free Volume, cubic feet 2.834 x 10 Iodine Form Fractions, percent Elemental 91 Particulate 5
4 Organic Filter Efficiencies for Iodine Forms, percent Elemental 95 Particulate 90 35 Organic Spray Removal Rates, per hour Elemental (Effective to 1.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />) 0.5 Particulate 0.2 Relative Concentrations, seconds per cubic meter 2.2 x 10~4 0-2 hours at 732 meters 8.2 x 10-6 0-8 hours at 3200 meters 5.7 x 10-6 8-24 hours at 3200 meters 2.6 x 10-6 24-96 hours at 3200 meters 8.0 x 10-7 96-720 hours at 3200 meters i
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TABLE 15.2 HY ROGEN PURGE DOSE The assumptions used to calculate the low population zone doses due to post-loss-of-coolant accident hydrogen purging are:
Power Level: 2772 megawatts thermal 6
Containment Volume: 2.83 x 10 cubic feet Purge Time: 30 days Holdup Time Prior to Purging: 24 days Purge Rate: 47 cubic feet per minute Charcoal Filter Efficiency of 95 percent and 95 percent for Elemental and Organic Iodine, respectively X/Q Value: 4-30 days (8.0 x 10~7 seconds per cubic meter)
Estimated Consequences LPZ Doses, Rem Thyroid Whole Body 11
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TABLE 15.3 ESTIMATED LOSS OF COOLANT ACCIDENT DOSE RESULTS i
Doses, Rem Thyroid Whole Body Exclusion Area Boundary 0-802 see 163.6 1.73 802 see - 2 hrs.
115.8 4.68 i
279.4 6.41 s
LPZ 0-802 sec.
6.08
.064 802 see - 8 hrs.-
10.56
.410 8-24 hours 3.76
.110 1-4 days 3.38
.027 4-20 days 2.74
.013 26.52
.624 a
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TABLE 15.4 ASSUMPTICMS FOR STEAM LINE 3REAK & STEAM GENESATOR TLBE RUP'l)RE ACCICENT5 Core Power Level 2772 MWt 2-hour rotative concentration at exclusion bouncary 2.2 x 10 seconds per cubic meter Iodine water / steam decontamination factor 10 Scurce spike factor after accidents 500 Iodine and noble gases fuel activity in gaos 10 percent percent fuel with clad failures after rod ejection accident 23 percent
- ercent fuel reaching initiation of melting 0 percent Coolant equilibrium concentrations as limited by Technical Specifications
- Reactor Coolant. Iodine-131 Equivalent without Iodine s,;,ike 1.0 microcuries per gram Reactor Coolant. Iodine-131 E uivalent with Iodine spike at 2S27 megawatts thernal 60.0 microcuries per gram Reactor Coolant, Nchie Gases 100/f aferocuries per gram secondary coolant. Iodine-131 Ecuivalent 0.1 mic ocuries per gram "All releases carougn Secondary System I
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m TABLE 15.6 OOSE RESULTS FOR STEAN UNE BREAK. STEAM GENERATUR TLBE auPTURE AND CONTROL E00 EJECTION ACCICENTS THYR 010 WHOLE BODY (REM)
(REM)
DOSES (732 MTERS)
(732 METERS)
Tube Rupture Accident 1.5 less than 10 Tube Rupture Accident with Coincident Iodine Spike 12.0 less than 1,0 Steam Line Break less than 1.0 less than 1.0 Loss of Offsite Power less than 1.0 less than 1.0 Loss of Offsite Power with Coincident Iodine Spike less than 1.0 less than 1.0 Rod Ejection Accident Case I*
4 less than 1.0 I
Case 11**
34 less than 1.0 Red Ejection Accident (0-8 hour Low Population Z ne Relative Concentration Value 8.2 x 10'6 seconds per cubic meter) 2.0 less than 1.0 Rod Ejection Accident (8-24 hour Low Population Zone 5,7 x 10'pncentration Value Relative seconds per cubic meter) less than 1.0 less than 1.0
- Releases through the containment.
" Releases througn the seconcary system.
15-9
..m TABLE 15.2 ASSUMPTIONS FOR AND CCNSECUE%25 CF A_
PO5TULATED FUEL MANGLING ACCICENT_
i 2772 Megawatts-therwal Power Level 1.7 Power Peaking Facter 3 years Operating Time 208 Number of Rods Failed 38.21 6 j
Number of Rods in Core Fraction of Inventory in Gap:
10 percent 1
Neale Gases 10 percent j
Iodinas i
Effective Iodine Cecontamination Factor 100 in Pool Filter Efficiencies:
90 percent Elemental Iodine 70 percent Organic Iodine Iodine Fractions Leaving Pool 75 percent Elemental 25 percent Organic
)
72* hours
, Shutdown Time Q/X Relative Concentration Values 2.2 x 10'# seconds per cucic meter 0 - Z nours ac 73Z meters 0 - 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at 3200 meters 8,2 x 10-6 seconds per cubic meter u
Estimated Consecuences:
Ocs e, rom Thyroid ancie Body 9
less than 1 Exclusion Area Scundary (732 meters)
Low Population I:ne Scunoary (3200 meters) less than 1 less tnan 1 9
e 15-10
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TA8LE 15.8 AS$UMPTIONS FOR AND CONSEOUENCES OF A POSTULATED GAS CECAY TAAK ACCICENT Gas Decay Tank Ruoture The assations used to calculate the offsite doses from a gas decay tank rupture were:
(1) Gas decay tank contains one complete pri. nary coolant loop inventory of noble gases resulting fmm operation with 1 percent failed fuel (94,000 curies of noble gases).
(2) The release is complete within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
(3) Meteorological assumptions are the same as for the loss-of-coolant accident.
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Estimated Consequences:
Exclusion Area Boundary Negligible
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(732 meters)
Low Population Zone (3200 meters)
Negligible
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