Monday, September 11, 2017

NRC Update on Florida's Irma- Beleagured Nuclear Power Plants

USNRC (September 11, 2017) NRC Continues to Respond to Irma

Turkey Point Unit 3, in south Florida, remains safely shut down, as it has been since Saturday. Turkey Point Unit 4 shut down automatically just before 7 p.m. Sunday evening due to a valve issue. The shutdown was uncomplicated, the plant is in a safe condition, and winds and rain have diminished at the site such that the plant staff exited their declaration of an unusual event at 4 a.m. Three NRC resident inspectors remain at the site, but the agency is now assessing steps to return to its normal inspection staffing within the next day or two.
At St. Lucie, also in Florida, operators are reducing power on Unit 1 due to salt buildup on insulators in the switchyard that supplies offsite power and plant employees are working to resolve this situation. St. Lucie Unit 2 remains at full power. Two NRC resident inspectors remain at the site, but it is expected that NRC will return to normal inspection staffing at this site, also within a day or two.

1 comment:

  1. COMMENT BY PavewayIII
    September 11, 2017 at 12:19

    Sequence of NRC reports: NRC Friday Event Notifications Turkey Point (3,4) 52952

    Thursday 23:14 – NWS Hurricane Warning issued

    Friday 00:06 – Notification – Emergency Declared/Offsite Notification

    Friday (no time specified) 'Updated' – no indication of what was updated
    (Convenient notification Friday at 00:06 ensures it won't be seen by public until Monday)

    NRC Monday NRC notifications

    Turkey Point (3,4) 52952
    Identical notification appears again

    Turkey Point (4) 52960
    Sunday 18:55 Reactor only running at 88% for some unknown reason - failure of loop 4C Steam Generator main feed regulating valve - Loop 4C S/G [Steam Generator] water levels drop

    - Emergency Operating Procedures initiated

    - Manual trip of reactor from 88% PWR (?)

    - Auxiliary Feed Water initiated as designed [normal response]

    - restored S/G water level

    - Emergency Operation Procedures exited

    - returned to General Operating Procedures

    - Reactor at 0% PWR; in Hot Standby

    For the textually challenged (me) here's a diagram:

    The blue juice in one of the 4 steam generators go too low, so they pumped more in. The red juice got angry at all the commotion so the operators shut the reactor down. The reactor operators don' t like it when the red juice wants to leave the containment building and comes to visit them.

    Unusual that reactor was at 88% – something else was happening that they're not saying.

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    PavewayIII PavewayIII
    September 11, 2017 at 12:47 pm Log in to Reply

    Either the manual scram (if unplanned, i.e., not part of planned shutdown) or the activation of the steam generator aux. feedwater system would have required reporting.

    The steam generator main feedwater valve is stuck/closed/secrewed up, so they can't run steam through the turbines, cool it down and pump it back into the steam generators through that valve like normal. That'e the normal route for the secondary steam loop. Instead, they're pumping auxiliary water into the steam generator thorough a different valve, and then just dumping the steam produced into the air outside the plant. That steam/water *shouldn't* be radioactive like the primary loop steam/water, but isn't completely radiation-free, either.

    In any case, the reactor doesn't care as long as the steam generators are removing enough heat from the primary loop reactor water. That's the red loop in the diagram that goes in/out the 4 steam generators' U-tubes.


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