4x4 (or other) sqare of METL don't allow pressure . < In TPT there aren't any material(without walls) which not allow pressure.
New radioactive mode .( PLUT and URAN are radioactive materials ) Radioactive radiation(RRAD) will be change other materials (like NEUT but "RRAD" would change differently.
Create new RRAD view.
(Optional: RRAD should comprise: ALPHA RAY , BETA RAY and GAMMA RAY > This rays can be in the form of three merged waves , and every of them went or stayed in the various materials.)
Sorry for my English but I better read than write or speak :)