ARMI should be better at helping people identify what a PIN is.

[john-science]

I believe ARMI does not do enough to help people identify what a PIN is. And it doesn't help handle the different types of pins in obvious ways.

NOTE: ARMI has a Flags.Pin, but it does not appear to be widely used, or otherwise solve the problem.

1. This is a risk. There are currently several different implementations in ARMI and downstream projects, all doing slightly different things. Without consistency, there is the possibilities of error.
2. We already know that the current tools are inconsistent.
3. This is a solvable problem, once we all agree on the pathway.

Examples of different "count the pins" implementations

https://github.com/terrapower/armi/blob/drewj/pin-indices/armi/reactor/blocks.py#L2167-L2168
Examples:

armi/armi/reactor/blocks.py

Line 994 in 83d6292

def getNumPins(self):

armi/armi/reactor/blocks.py

Line 1428 in 83d6292

def getPinLocations(self) -> list[grids.IndexLocation]:

Ideas for Solutions

• Make solid, 100% use of the current PIN flag, such that people can rely on it.
• Add a POISON flag, for LWR folks?
• add some helper methods: getNumPins(), getNumFuelPins(), getNumPoisonPins(), etc and fix them using flags
• a Pin(Composite) with nested Composites inside Composites
• Block.pins

[john-science]

@albeanth @keckler @mgjarrett @jakehader @onufer @drewj-tp @wcscherer I am happy to take the brunt of the work needed to make this happen. But I am eager to make "how many pins" as easy as possible for my userbase. (Considerations: multiple pin types, non-fuel pins.)

[john-science]

@mgjarrett said:

Flags.PIN allows for the simplest logic within code but puts the most burden on the user to update every input to explicitly put a pin flag on everything. It's probably the best solution, though.

I am surprised this is a lot of burden. But that's still good information.

[keckler]

I do not see the relevance of the suggested POISON flag to this ticket, or why it would be LWR specific. What is the context there?

[drewj-tp]

I think it's in reference to the PIN_COMPONENT magic list

armi/armi/reactor/blocks.py

Lines 53 to 61 in fcc30f4

	PIN_COMPONENTS = [
	Flags.CONTROL,
	Flags.PLENUM,
	Flags.SHIELD,
	Flags.FUEL,
	Flags.CLAD,
	Flags.PIN,
	Flags.WIRE,
	]

I may be responsible for indicating POISON would be specific for LWRs in a convo w/ JS. They're used in more reactors than just LWRs

[keckler]

I think that making people use the PIN flag is probably the most straightforward. But I think it also starts to become hairy, because in reality a given pin is a composite of multiple components. So should the user put PIN on the fuel, clad, gap/bond, and wire (if existing) components? That starts to become complicated, because in some cases a user might have different mults for different pieces of the composite pin (for instance, if only some of your pins have wire wraps, or you have different fuel materials in some pins).

I think that the only sure way for ARMI to be able to KNOW what is a pin and what is not is for people to define their blocks with grids. Honestly this is not that hard to do.

[albeanth]

is for people to define their blocks with grids. Honestly this is not that hard to do.

If we went this route (which knee jerk reaction I agree with, btw), ARMI would need to provide a new helper method to quickly pull the pins by latticeID on a composite. E.g., something like composite.getPinComponent(pinNumber: int) where pinNumber is the latticeID provided in the blueprints. This might get complex to do at the composite level though; at the component and block, it's simpler, but at the assembly, do you return the pin components over the whole assembly? Similarly at the core level.

[john-science]

@keckler We could use Flags.PIN for the pins themselves, and a Flags.ROD to label the clad, wire, etc etc.

Just thinking aloud.

[drewj-tp]

See also

armi/armi/reactor/blocks.py

Lines 53 to 61 in a9f0f45

	PIN_COMPONENTS = [
	Flags.CONTROL,
	Flags.PLENUM,
	Flags.SHIELD,
	Flags.FUEL,
	Flags.CLAD,
	Flags.PIN,
	Flags.WIRE,
	]

vs.

armi/armi/reactor/converters/blockConverters.py

Lines 488 to 502 in a9f0f45

	PIN_COMPONENT_FLAGS = (
	Flags.FUEL,
	Flags.ANNULAR | Flags.VOID,
	Flags.GAP,
	Flags.BOND,
	Flags.LINER,
	Flags.CLAD,
	Flags.WIRE,
	Flags.CONTROL,
	Flags.REFLECTOR,
	Flags.SHIELD,
	Flags.SLUG,
	Flags.PIN,
	Flags.POISON,
	)

[albeanth]

I know we (I) do this once more in an internal tool too. and yes, this list is different than either of those above.

FUN!