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The RFO Spike - General Info
The RFO Spike - General Info

 In the first post ( The RFO Spike - Introduction - http://caferadlab.com/thread-2356.html ) we looked at Dr. Ian Farlie's work surrounding the relationship between childhood cancers and the radiation spike during a ReFueling Outage ( RFO ).

 In the US there is currently no political party capable of forcing the nuke industry to reveal rad levels around an NPS during RFO. The nuke industry won't even alert the public when they plan on RFO operations. The standard reason has to do with 'market competition', but I think the real reason is that they know that if citizen radiation monitoring groups knew when to look they would be able to detect the rad spike.

 In order to use open source information we have to piece together and map out when unit RFO's will occur and the sequence of events that occur during the RFO to know where and when to look.

 The info contained in the Daily Reactor Status reports will be one of the main sources of unit activity we'll use to map out a general sequence of events during an RFO.

 This is the base page to access the daily reactor status data.

Each reactor follows one of two RFO schedules, either 18 or 24 months between refuelings. Once we know when a unit has refueled we can surmise it's next refueling and track the unit power to see when the RFO begins.

 Examples of the RS data can be viewed in the 'The Daily Dose' post

 In the daily Event Notices (ENs) there is a box that details the state of the reactor both before the event and after. Of particular use is the RX Mode info which helps define the sequence when an EN is posted during RFO.

These two charts define what those states mean for both PWR and BWR units.

RX Modes PWR | https://www.nrc.gov/docs/ML1210/ML12100A222.pdf |
Definitions 1.1
Westinghouse STS 1.1-7  
Rev. 4.0 Table 1.1-1 (page 1 of 1) MODES  
          |          | CONDITION(keff)%  | POWER(a)            | COOLANT TEMPERATURE (°F)

1 | Power Operation     | ≥0.99         | >5                       | NA
2 | Startup                  | ≥0.99         | ≤5                       | NA
3 | Hot Standby           | <0.99         | NA                       | ≥[350]
4 | Hot Shutdown(b)    | <0.99         | NA                       | [350]>Tavg>[200]
5 | Cold Shutdown(b)   | <0.99         | NA                       | ≤[200]
6 | Refueling©            | NA             | NA                       | NA
(a)    Excluding decay heat.  
(b)    All reactor vessel head closure bolts fully tensioned.
©    One or more reactor vessel head closure bolts less than fully tensioned.
RX Modes BWR | https://www.nrc.gov/docs/ML1210/ML12104A192.pdf  
Definitions 1.1
General Electric BWR/4 STS 1.1-7 Rev. 4.0 Table 1.1 - 1 (page 1 of 1)  

          |          | SWITCH POSITION  |  COOLANT TEMPERATURE(°F)

1 | Power Operation   | Run                                           |  NA
2 | Startup                | Refuel(a) or Startup/Hot Standby  |  NA
3 | Hot Shutdown(a)  | Shutdown                                   |  >[200]
4 | Cold Shutdown(a) | Shutdown                                   |  ≤[200]
5 | Refueling(b)         | Shutdown or Refuel                     |  NA
(a) All reactor vessel head closure bolts fully tensioned.
(b) One or more reactor vessel head closure bolts less than fully tensioned.  

By matching the RX Mode with the RFO day we can map out the RX Modes during an RFO.

eg If on RFO day number four the RX Mode is Cold Shutdown and then on RFO day number five the RX Mode is Refueling we know the Reactor Pressure Vessel (RPV) head is being or has been removed because Refueling is defined as ' One or more reactor vessel head closure bolts less than fully tensioned'.

One of the RX Modes not defined is Defueled which is self explanatory. ALL the fuel assemblies have been removed from the core.

The following are some of the unofficial modes, arranged in a stack.

Mode 10 - We need to find a way to make lots of money.
Mode 09 - Lets con the public and gov't into building a nuclear reactor.
Mode 08 - We have all the permits and financing.
Mode 07 - We got the thing built.
Mode 06 - Adding the fuel.
Mode 05 - RPV closed and testing.
Mode 04 - Heating it up.
Mode 03 - Ready to go.
Mode 02 - Going to full power.
Mode 01 - Run
Mode 00 - Oh crap!  Run . . .  RUN !!

In the next post of this series I'll show how I mapped out the RFO sequence so we know when the RPV is open.

Earthday - got some things to do. Laterz.

posted by Staup Knewkinus a Dane Gerous production. All human rights reserved.

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