ML20128E069
| ML20128E069 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 09/11/1973 |
| From: | Harold Denton US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 9212070463 | |
| Download: ML20128E069 (4) | |
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SEP 111973 fhlhS D. Skovholt, Assistant Director for Operating Reactors, L Oyy-CAS SYSTDI ACCIDENT ASSESSMENT FOR MONTICELLO - TAR-590 This is in response to your request for calculations to estimate the dose consequences of a break in the modified off-gas system proposed for Konticello (TAR-590).
The Accident Analysts Branch has evalueted the dose consequences of a postulated f ailure of the proposed off-gas system of the Monticello Nucicar Power Plant. Table 1 provides' the assumptions used in the calculation and Table 2 provides the calculated doses.
The analyeis considers a noble gas composition specified in G.E. Topical Report NEDO 10734 based on a release rate of 100,000 microcuries per second af ter a 30 minute delay. We have scaled this up to 350,000 microcuries per second after a 30 minute delay.
The analysis indicates that a failure of the Monticello off-gas system consisting of a total release within two hours of the contents of the delay line, and - five hold-up tanks, including staan jet air ejector isolation within one hour will result in a two hour whole body dose at the site boundary of 6.5 ren, in excess of the 5 rem whole body guideline we entrently use for.
plants of this vintage to define Category I seismic design requirements.
(New plants would have to meet a 500 nr limit.)
The off-gas release rates for Monticello should be limited to 270,000 microcuries per second.af ter a. 30 mismte delay in order to keep the potential whole body dose below 5 rem at the site boundary.
This work was performed by Joel E. Kohler of the Accident Analysia Branch.
$ Natl signed by R.' R, p.og Barold R. Denton, Assistant Director for Site Safety Directorate of Licensing cet See next page.
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s TAht.E 1 0FF CAS ACCIDENT ASSltMPTIONS Power Level (MWt) 1630 Number of Units Using Common Delay Line 1
Condenser Leak Rate (SCFM) 28 Number of Hold-Up Tanks 5
liold-Up Time per Tank (hrs.)
12 Delay Time to Tank (min.)
30 Noble Gas Release Rate (after 30 minute delny) (uct/see) 350,000 Iodine Release Rate (uC1/sec)
.5 3
Safety Guide 3 Neteorology (sec/m )-
2.0 x 10'3 Minimum Site Boundary (meters) 500 Accident Duration (hrs.)
2 Isolation Time for Steam Jet Air Ejector (hrs.)
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TABLE 2 Th'O HOUR SITE BOUNDARY DOSE ($00m) b* hole Body Dose
_ Thyroid Dose Steam Jet Air Ejector 3.10
.002 Delay Line
.569
.001 Tank 1 1.92
.452 Tank 2
.418
.425 Tank 3
.214
.403 Tank 4'
.142
.383 Tank 5 2
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.365 4
TOTAL 6.47 2.03 i
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