Sky-High Radiation Found in Fukushima Fish

[PamW]

58. Damn it, Kris - I said PWR!!!

Last edited Mon Jan 28, 2013, 11:41 AM - Edit history (1)

Kris,

Damn it, Kris - I specifically said PWR. Contrary to your ill-conceived contention above that I was using a "dishonest tactic" in switching to a PWR, my post was NOT dishonest. Do you know why? Because BWRs don't have atmospheric dump capabilities. ONLY PWRs have atmospheric dump capability.

Contrary to being a "dishonest tactic"; there's was no switch. The presence of atmospheric dump implies the reactor is a PWR. Nothing dishonest except Kris' tactics.

Courtesy of the NRC, here is the diagram of the PWR system:

http://www.nrc.gov/reading-rm/basic-ref/students/animated-pwr.html

Note that the only water loop that goes through the reactor is the "primary" loop with the yellow / red color. Since it is the only loop that goes through the reactor, it is the only loop that is slightly radioactive.

As I stated in my first explanation, the purpose of the atmospheric dump is so one can stop the turbine for a short time for adjustment or repairs. In order to stop the turbine, you have to stop the flow of the steam through the turbine, which means you have to vent the loop that is the working fluid of the Rankine steam cycle. In the PWR, that loop doesn't go through the reactor, so that water is non-radioactive, and hence one can vent it to stop the turbine.

Now here's the diagram of the BWR system:

http://www.nrc.gov/reading-rm/basic-ref/students/animated-bwr.html

The BWR doesn't have steam generators. Note that in the BWR, the Rankine working fluid that goes through the turbine also goes through the reactor. In the BWR, the reactor coolant and Rankine working fluid are one and the same loop. Since this loop goes through the reactor, it is radioactive.

Because of that, BWRs DO NOT have atmospheric steam dump capability

In a BWR, if you want to stop the turbine; there is a valve called the "turbine bypass valve". When you want to stop the turbine; the turbine bypass valve diverts steam from the reactor directly to the condenser without going through the turbine. Instead of dumping steam to the atmosphere, the steam is condensed, and the heat is dumped to the environment by the water loop that cools the condenser.

So if someone says a nuclear reactor plant is doing an "atmospheric steam dump"; then that reactor can NOT be a BWR since they don't have atmospheric dump capability. They have the turbine bypass to the condenser in lieu of atmospheric dump.

Therefore, if a nuclear plant in doing an atmospheric dump; it MUST be a PWR. In the PWR, the Rankine working fluid is NOT radioactive, and so it DOES NOT release radioactivity to the environment.

Thus, bvar and Kris are BOTH WRONG.

PamW