Thermocouple hot temperature is less than its cold...

Error message on RTG: "Thermocouple hot temperature is less than its cold temperature".  Not sure I understand how that couple be the case / reads like an error to me?

I was trying to implement Gold-198 as a mod, mostly for the sake of it -- the half life is hilariously short at 2.69 days, and the beta decay power is non-trivial at 1.372 MeV.  I don't expect this to be practical -- I was implementing it to see how high the cost would go, and for the "build a ship out of gold" challenge.  This produces a ridiculously high radioactive decay specific power of 1.99 MW / kg, which I think, along with the short half life and the requirement of an operational RTG for 6 months, must be overflowing / underflowing something.

Elements.txt:Element Gold
Symbol Au-198
AtomicMass 198
AtomicNumber 79
MolarMass_g__mol 197.9682
FirstIonizationEnergy_kJ__mol 890.1
MeanGammaRayMassAbsorptionCoefficient_cm2__g 6.953E-02
HalfLife_s 232862.688
BetaDecay_keV 1372.8
SolarAbundance 0
Emission Gold
TransmutationParents Au

Radionuclides.txt:Material Gold-198
Elements Au-198
ElementCount 1
Density_kg__m3 19398
YoungsModulus_GPa 79
ShearModulus_GPa 27
SpecificHeat_J__kg_K 128
MeltingPoint_K 1337.33
BoilingPoint_K 3243
ThermalConductivity_W__m_K 320
ThermalExpansion__K 14.2e-6
Resistivity_Ohm_m 22.41e-9
RefractiveIndex Gold
RoughnessCoefficient .3