Reliable data on local gamma dose rates which are based on measurements are a prerequisite for well-founded decisions on emergency measures to protect the public in the case of a severe reactor accident.

Since the local density of on-line dose rate monitors is restricted, interpolations between the detector locations must be performed in real time using advanced emergency codes.

The local fine structure of the gamma dose rate originating from cloud and ground radiation is determined with refined dose modules.

Correlation factors between maximum and mean doses and the gamma dose rates measured at the detector locations are defined.

Absolute release terms need not be known since relative quantities are sufficient to calculate the correlation factors.

Results are given for the site of the nuclear plant of Obrigheim.