Del. has a nuke plant event

[ensho]

The Salem 1 nuclear reactor is shut down today because of problems with “grassing,” the blocking of cooling water intakes by vegetation, officials said. Salem 1 was manually taken off line Thursday about 4 p.m. and remains down today as operators attempt to clear debris causing the problem. Grassing is caused by vegetation such as phragmites and other weeds and grasses growing along the Delaware River’s shoreline and its tributaries becoming dislodged and floating downstream in the river. Grassing can be especially troublesome in the spring when dead vegetation moves downstream. High tides and heavy rains — like the conditions seen last weekend — can dislodge even more of the dead materials and carry them downstream. Salem 1 and its neighboring Salem 2 reactor together draw in and return 3 billion gallons of water from the river each day for cooling purposes. Hope Creek, the third reactor at the Artificial Island nuclear generating
complex here, draws in only about 58 million gallons a day from the river because the plant has a cooling tower which recirculates cooling water.

Salem 1 had been operating at reduced power — 89 percent — at the time it was shutdown after the grassing issue became more severe, according to Joe Delmar, spokesman for the plants’ operator, PSEG Nuclear. The Nuclear Regulatory Commission said today that the shutdown was handled properly. “Our resident inspectors assigned to Salem observed the shutdown from the plant’s control room and identified no concerns with operator or equipment response,” said NRC Spokesman Neil Sheehan. “The inspectors have also concluded that PSEG’s response to an increase in grassing this week was appropriate and in accordance with plant procedures used during the grassing season.” Delmar said he could not estimate when Salem 1 would return to service. “River grassing continues to be an operating challenge for the Salem plants,” Delmar said. “Our operators are trained to take
appropriate measures when need as they did yesterday to ensure the safe shutdown of the plant. “We will continue to explore opportunities to make plant modifications to lessen the impact of grassing on our plant operations,” Delmar said. The Salem 2 reactor was taken off line on April 9 for a scheduled refueling outage. Each of the reactors generates enough power for 1 million homes.
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http://hisz.rsoe.hu/alertmap/index2.php

[ReggieVeggie]

1. they exclusively use river water for cooling?

that doesn't make sense

[ensho]

2. 3 billion gallons a day - and when that water come out of the other end

its just lovely

[NutmegYankee]

4. It's just warmer.

It is not radioactive because it never gets near the reactor. It cools the spent steam back into water through heat exchangers. All steam cycle plants (Coal, Gas, Nuclear, garbage, wood) use cooling water to condense the steam. It's simply thermodynamics at work.

[MH1]

5. Yep, and temperature doesn't matter at all to river life.

Not at all.

:sarcasm:

(but you are right that normally there shouldn't be any significant contamination other than thermal)

[ensho]

6. kick

nt

[NutmegYankee]

7. It depends on the volume of cooling water.

If the river is large enough and flows enough volume, the impact is minor. If the river has low flow, as has happened in Georgia a few summers ago, the plant is forced to reduce power to avoid killing fish. Are there irresponsible plants owners out there? yes there are. But most follow the environmental regulations that protect aquatic life.

No need for snark. I was addressing what I believed to be a reference to radiation versus heat.

[NutmegYankee]

3. That's common for steam condensers at any power plant.

Cooling towers are used if there isn't an ideal supply of water nearby to serve as a heat sink.

On edit: There are separate loops for cooling the reactor. The river water takes the heat away from the reactor cooling system through heat exchangers (a large vessel, shell, with tubes running through it such that the fluids never touch but can exchange heat) and never is in contact with the water that cools the reactor.