This proposal forms part of our larger study into the mechanics of nickel based alloys. In particular we are attempting to correlate the intergranular stress development in certain Inconel alloys with locations of failure in reactor feeder pipes. While uniaxial stresses are easy to impose in tests they are not necessarily representative of the stress state in a real system. Hence, although models appears to be well validated under these conditions, the next step to improve and verify the predictions of polycrystalline models in IN 690 and 800 is the in-situ measurement of lattice strains under plane strain conditions.