Е, потруди се де за някакъв коментар на икономическите разчети. Или е по-лесно да вдигаш лозунги за супер-реакторите?

А ето ти описание на инцидента (надявам се, че си добре с английския):

In March 1979, an event occurred at the Three Mile Island Unit 2 that resulted in the first case of melted fuel in a full scale commerical nuclear power plant. There had been prior cases of small scale fuel melting, e.g. the Fermi 1 reactor near Monroe, Michigan. TMI-2 was a Babcock & Wilcox unit with a vertical once-through steam generator. In the event a valve in the secondary system closed and initiated the sequence of events.

The sequence of events was:
1. A valve in the condensate system (between the condenser and the pump on the secondary side) failed closed, which reduced the amount of water being supplied to the steam generator; the main feedwater pumps and the turbine tripped within seconds.
2. The design of the vertical one-through steam generator is such that there is not much water on the secondary (non- radioactive) outer side of the steam generator tubes that will boil to steam when the plant is at full power and the reactor continues to put out full power; thus all the water on the secondary side was rapidly converted to steam within minutes. The emergency feedwater pumps, which started as expected, were unable to inject water into the steam generators because several valves in the system were closed.



3. The reactor continued to heat the reactor coolant. The reactor coolant pumps continued circulating the water to the steam generators, however no heat could be removed by the secondary side since there was no water in the steam generators. The reactor coolant system started to heat up.
4. Pressure rose in the reactor cooling system until the reactor shutdown. A power operated relief valve opened in the line between the pressurizer and the quench tank.. This valve failed to reclose when it was supposed to - after pressure dropped below the setpoint for closure. This relief valve continued to discharge to the quench tank. The fact that the valve was open allowed steam to continue discharging to the quench tank. Pressure dropped in the reactor cooling system because the valve was still open (however, due to poor control board design and a failure to indicate the valve position properly, the operators did not know the valve was open). The quench tank has a rupture disc that opens at about 10-12 pounds per square inch. When this happened, the steam was released to the containment.
5. The pressurizer is normally at about 650F. As pressure dropped in the reactor cooling system, eventually water in the upper-most area of the reactor (about 10-15 feet above the fuel) flashed to steam. The indicated water level in the pressurizer stayed high (the relationship between the pressurizer and the reactor was like a manometer).
6. The operators turned off the emergency water injection pumps because they thought there was still water in the pressurizer.
7. The operators turned off the reactor cooling pumps because they were concerned about damage due to potential excessive vibration.. This resulted in a steam void forming in the reactor coolant loop. In addition, a steam bubble formed in the upper part of the reactor above the fuel. Eventually as the fuel heated, this void expanded. Eventually, the fuel cladding material overheated. It is likely that some hydrogen was produced by a chemical reaction between the zircaloy clad and the steam in the reactor. In addition, the hydrogen normally present in the reactor cooling system (used to reduce the presence of oxygen and subsequent corrosion in the system) was released to the containment through
8. At one point, containment pressure rapidly spiked to 28 pounds per square inch; then rapidly dropped. This was most likely due to the chemical reaction of hydrogen with the oxygen in the containment.
9. Water was added to the reactor cooling system and the level raised in the pressurizer until cooling of the reactor was assured.

А, забравих - да, по-старите реактори в Европа са по-безопасни от нашите малки. Ако си специалист от по-горното описание ще знаеш защо.

Погледни към себе си

Редактирано от exPesho на 07.03.02 17:38.