Bomb Power Indicator

The BPI indicator dial seen on the wall of an underground ROC post during a training exercise

Bomb Power Indicator, also known by the acronym BPI, was an instrument built to detect nuclear explosions and measure the peak overpressure of their blast waves. It was used at the twenty five British Royal Observer Corps (ROC) controls and nearly 1,500 ROC underground monitoring posts, across the United Kingdom during the Cold War.[1]

Overview

The instruments, operated by volunteers, measured the level of peak-overpressure at the instrument's location.[2] Once readings had been combined with information provided by the Ground Zero Indicators it would be possible to estimate the size of the nuclear explosion in megatons. Detailed BPI information was backed up by the automatic AWDREY readings.

The BPI was designed and built by the Atomic Weapons Establishment at Aldermaston. The design was tested for performance and accuracy using real nuclear explosions at the 1957 nuclear weapons tests at Kiritimati (or Christmas Island), after being mounted on board a ship. A number of BPIs were also tested in Australia during the Operation Buffalo series of nuclear tests, with units located at various distances from ground zero.

Operations

Above ground, a pair of circular plated baffles would be affected by the passing of the blast wave. The detector was connected by a steel pipe to the indicator dial below ground in the protected monitoring post. The dial was wall mounted and measured readings from 0.1 to 5 pounds per square inch peak overpressure. Readings below 0.3 pounds per square inch were noted but not reported.

The baffles were normally stored below ground and only screwed onto the top of the pipe at the start of exercises or at Transition To War. Outside of operations the BPI pipe was protected by a screw on cap and there was a drain valve at the base of the instrument to remove any excess rainwater.

If the BPI registered a reading of 0.3 or higher the operator would wait ten seconds before pressing the reset button and making a report to the group control. One minute after a BPI reading an observer is sent above ground to change the photographic papers in the Ground Zero Indicator.

Codeword

Royal Observer Corps reports following a reading on any BPI were prefixed with the codeword "Tocsin" e.g. "Tocsin Shrewsbury 56 post - (time) oh five fifty five - pressure two point six".

See also

References

  1. ^ Lee-Frampton, Nick (1985). "Protect and survive". New Zealand International Review. 10 (2): 25–27. ISSN 0110-0262.
  2. ^ Riley, Hazel; Jamieson, Elaine (2006). The Historic Landscape of the Quantock Hills (DGO - Digital original ed.). Liverpool University Press. p. 158. ISBN 978-1-905624-29-4.

Content Disclaimer

Informasi ini disarikan dari Wikipedia dan disajikan kembali untuk tujuan edukasi. Konten tersedia di bawah lisensi CC BY-SA 3.0. Kami tidak bertanggung jawab atas ketidakakuratan data yang bersumber dari kontribusi publik tersebut.

  1. The information displayed on this website is sourced in part or in whole from Wikipedia and has been adapted for the purpose of restating it. We strive to provide accurate and relevant information, however:
  2. There is no guarantee of absolute accuracy. Wikipedia is an open, collaborative project that can be edited by anyone, so information is subject to change.
  3. It is not intended to constitute professional advice. The content displayed is for informational and educational purposes only. For important decisions (e.g., medical, legal, or financial), please consult a professional.
  4. Content copyright. Wikipedia is licensed under the Creative Commons Attribution-ShareAlike License (CC BY-SA). This means that content may be reused with appropriate attribution and shared under a similar license.
  5. Responsible use. Any risk arising from the use of information from this website is entirely the responsibility of the user.