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Nuclear Plant Batteries

  1. Jul 24, 2017 #1
    It seems that the batteries installed at nuclear power plants would have been one of the largest scale applications of battery technology prior to the development of battery storage stations for utilities. I'm wondering what kind of technology they use(d) and what kind of lifespan, capacity, and discharge rate they might have. If nuclear power had become more common could the demand for nuclear power station batteries alone have helped to significantly advance battery technology?
  2. jcsd
  3. Jul 24, 2017 #2
    I don't believe nuclear power plant batteries are any different power plan batteries in general.
    Here's a wiki article:
    Of course, they've made news recently:
    Also, there is another aspect to this:
    Look about 25% down this page:
  4. Jul 25, 2017 #3
    The batteries in a nuclear station aren't really very large. They provide power to the instruments and controls, mostly. There are a few DC motor operated valves but those have small motors and usually will stroke the valve once under design conditions, to move the valve to the "safe" position. Normally there are 4 safety related batteries. These are just a bunch of lead-acid batteries tied together to make 125 volts DC. Typical size for each is ~1800 amp-hours. If I did the arithmetic right that's about 225 kw-hr each. The plant will usually have a couple more non-safety batteries to power equipment related to the turbine generator. So say six time 225 or 1350 kw-hr. The grid batteries mentioned above are in the tens of MW-hr range, that's a lot bigger.
  5. Jul 26, 2017 #4
    The batteries are "small" compared to a ship. My vital batteries are 58 large cells per division. I have 4 DC divisions in my plant. It's a boiling water reactor. They are normal lead acid batteries with plates. A couple hundred amps at best (although we don't have enough load for that).

    The division 1/2 batteries can only last 4 - 6 hours with load shedding. They do not power any emergency cooling pumps. They do provide valve power for RCIC (steam turbine driven aux feed) and power for the control circuits. They power the vital bus inverters for engineered safeguard logic, reactor protection logic, breaker control power, and a number of accident monitoring indications.

    You can't run any major equipment with them. But the control logic and indications are invaluable, in addition to breaker close/trip power, because when you do get offsite AC power back you need that to close the feed breakers in.
  6. Aug 3, 2017 #5
    So there are batteries for the pumps, they just can't actually run them? I thought the batteries could actually run the pumps and would thus be in the MWh range.
  7. Aug 4, 2017 #6
    The batteries are for control power and instrumentation.
  8. Aug 7, 2017 #7

    jim hardy

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    They're about a thousand times smaller than you imagine .
  9. Aug 7, 2017 #8
    Are there any plans to make more extensive use of batteries for future nuclear power plants or modernize existing plants to use them as safety systems?
  10. Aug 7, 2017 #9
    Gen 3+ designs use passive cooling features like elevated water tanks. The batteries are used to open the valves needed for passive cooling and that's it.
  11. Aug 23, 2017 #10


    Staff: Mentor

    Why? Diesel generators make pretty good backup. Of course diesels are imperfect (Fukushima), but so would batteries be imperfect.

    Batteries have a KISS advantage over diesel, but diesel has the advantage of trucking in more fuel from off-site allowing for almost unlimited energy production.
  12. Sep 4, 2017 #11
    Batteries are becoming price competitive with diesel engines for providing peaker power. If a nuclear power station has a battery storage site located nearby it could use that to help with safety, especially if there are some renewable power units nearby that feed power to the storage unit.
  13. Sep 4, 2017 #12
    Just some numbers.

    I need around 12 MW of power for 30 days for the class 1E power system to meet its required mission time. That's 8.6 gigawatt hours. That's a LOT of battery capacity. That's going to sit there at 100% state of charge for decades. On top of the high powered inverters to take the battery voltage and boost it to 4160V or more to power a large emergency core cooling pump. It's a real technical challenge and extremely expensive and complex compared to diesels. In my opinion.

    Also it's not wise to use power generation sources outside the plant (renewable, hydro/solar/wind) to meet minimum energy requirements. You don't know what's going to remain functional if it's not in a bunkered seismic class 1E enclosure. The only exception is Oconee's hydro dams instead of emergency generators. However there's a lot of weird exceptions with that and I wouldn't expect that to ever happen again.
  14. Sep 4, 2017 #13

    jim hardy

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    Megawatt size inverters and chargers do not though.
    By volume, diesel fuel enjoys an energy density advantage over Li-Ion batteries of roughly 17::1
    In a long term blackout as after a hurricane the diesel tank is easily refilled by tanker truck.
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