Re: Doserates in Turbine Hall

[jgbarnes@ix.netcom.com (JAMES BARNES)]

>
FROM:
    Jim Barnes, CHP
    Radiation Safety Officer
    Rocketdyne Division, Rockwell Aerospace
    jgbarnes@ix.netcom.com


You wrote: 
>

>A question for all Power Station RP guys.  Has anyone done a study on 
>the doserates in the turbine hall of a 900 MWe PWR in the event of 
>severe fuel damage (3.9% enriched) and a steam generator tube rupture 
>following soon after.  If so, what were the assumptions, results; and 
>did you consider the installation of a doserate alarming device in 
>the turbine hall to warn people in the vicinity?

-------------
This is a fairly common design-basis accident scenario.  My experience 
is with a 900MW+ Westinghouse reactor.  The scenario was described in 
the FSAR for the plant.

The scenario follows the following logic:

1)  A core rupture occurs.

2)  Activity circulates in the primary loop.

3)  A steam generator rupture occurs.

4)  Activity circulates into the secondary loop.

5)  The activity is carried in the secondary steamlines out of 
containment.  This activity is detected by rad monitors installed on 
the steam lines as the lines exit containment.

6)  The activity is carried into the turbines, then into the main 
condensor.

7)  The activity (nor primarily nobles gases) are removed as 
non-condensible gases by the vacuum eductor to the main condensor.  The 
noble gases are emitted through the eductor where they are detected by 
a monitor installed on the eductor discharge.

I recall there were two turbine floor monitors, but don't think they 
are considered as primary indicators of the event.

I don't recall any specific numbers; however I seem to recall that they 
had been calculated.

I believe the NRC publishes a "standard" tech spec for this reactor 
class.  You might be able to get more details from them.  You also 
might try contacting Westinghouse directly regarding the design.

Hope this is helpful.
>