Radioactive Incident Monitoring Network (“RIMNET” – UK)

One of the lesser known networks in the United Kingdom is Radioactive Incident Monitoring Network or “RIMNET.” This network was set up in 1986 following the accident at the Chernobyl nuclear station in the Ukraine as part of the National Response Plan.

Rimnet is designed to monitor radiation dose across the entire United Kingdom (a map of all sites can be found here [PDF]) and relayed to a computer in London at the Department for Energy and Climate Change for near-immediate alerts to rises in radioactivity. It is managed by the Met Office. There are 92 sites spread across the UK in all areas both close to major cities, in rural areas and near or in MoD properties.

Rimnet was developed in three stages:

  • An initial system, RIMNET Phase 1, was installed in 1988 as an interim solution
  • The Phase 2 system operated until January 2005
  • Phase 3 went live in 2006

There was a detailed article in the journal Radiation Protection Dosimetry in 1993 detailing Phase 2 (Radiat Prot Dosimetry (1993) 50 (2-4): 171-176.) (see

The article gave a technical summary of the systems in use:

System Configuration
Monitors Type: Geiger-Muller
Measurement range: background to 3 mGy.h -1
Temperature –20oC to +40oC
Windspeed: up to 100 knots
Humidity up to 95%
Main CDF (“Central Database Facility” Configuration: two Digital VAX clustered processors
RIMNET workstation terminals, System Manager console and data storage
Communication Links Combination of leased lines, public data network (packet switched network for PCs), local Ethernet connections

In some ways RIMNET was a civil companion to the UK Warning and Monitoring Organisation before it was disbanded in 1991. However by Phase 2 of RIMNET it was much more sophisticated in collecting and transmitting radiation doses than the UKWMO ever was. RIMNET consisted of 90+ collection sites, fully automated than did not need personnel to man them. RIMNET, now at Phase 3, continues to monitor for radiation levels to this day.