Southern California Edison Model 120
| Southern California Edison Model 120 | |
[[File: |200px]]
| |
| Company | Southern California Edison |
|---|---|
| Produced | September 1982 and 1988 |
| Type | Pneumatic |
| Sound output | 120 |
The SoCal Edison (SCE) 120 or Model 120 was a SoCal Edison manufactured 120 dB siren which was designed by John Glenn Powell. He is a now retired worker that worked at the San Onofre Nuclear Generating Station located in San Clemente, California and was also a sound engineer. There were 22 of these sirens produced with one being never installed which is now privately owned. 17 were installed in September 1982 to add into a system of 29 Federal Signal STL-10s that were installed in October 1981, and later in 1988 4 additional locations were installed. The reason these sirens were made is because there was no other siren available that would meet the plants needs. The only sirens that were available on the market that have the range the plant was looking for were rotating directional sirens only, of which the plant wanted Omnidirectional only sirens. They did look into ACA Cyclones which was the most powerful omnidirectional siren available, but they realized it didn't have the coverage the plant wanted being about 3,000 or so feet less the then plants range requirement, and the fact that they have massive 50 Hp motors which was overkill for a siren with such a range of only about 4,000ish feet. The other reason is because the STL-10s underperformed in all areas they were placed in, as well as federal lying to SoCal Edison about the STL-10 being 120 decibels and having the specific effective range that the plant required (which was about 6,000 or more feet effective range) to cover the EPZ due to the hilly terrain of the jurdisctions in the EPZ.
So starting in late 1981, Model 120 prototypes started to be constructed and tested, with the final designed units being completed in August 1982, and the first 17 installed in September 1982, and later on 4 more in 1988 to cover new housing and business development in a part of the city of San Clemente that was being constructed around 1987 bringing the total to 21 Model 120s and a total number of 50 sirens with the already existing 29 STL-10s. Originally the plan was after the Model 120s installed, a now total of 50 sirens were going to be all Model 120s which means swapping out the existing 29 STL-10s with 120s making the system only, but this plan was dropped shortly afterwards due to the whole siren thing causing delays to the plant by not having a ready siren system by 1981 which was the original year for the plants 2 new reactors that just finished construction, Units #2 and #3 to begin operation, but due to the STL-10s originally bought not meeting the plants needs by not effectively covering the EPZ, they had to find another siren that meets the plants needs in order for the plants new reactors to start operations which caused a delay for over a year, this also happened around the same time the NRC required Nuclear plants to have siren systems, but until SONGS get sirens that can perfectly cover the 10 mile EPZ, the plants new reactors could not begin operations, and the plants original reactor that was the first reactor to be built in 1968 (Decommissioned in 1992 and completely demolished by 2006) Unit #1 could not be restarted until the siren system is fully operational and effectively covers the EPZ. So after the Model 120s went up, to end the delays and costly over 1 million per day it takes to get the siren system ready and stop holding up the plant from starting, it was decided to just keep the underperforming STL-10s and just add 21 Model 120s in areas that need coverage to get the EPZ effectiveness up to code for the plants original reactor to restart, and the new reactors to start. After a successful system test in October of 1982, the plants 2 new reactors began operation a few months later in early 1983.
For around a decade, they were thought to be "Toshiba" sirens, because they were pneumatic and people just assumed they were made by Toshiba, who also made pneumatic sirens. The Model 120 is a Pneumatic siren, meaning it requires an external air source to produce sound. The sound is chopped by a rotor, which sits inside a hollow cylinder, or stator, which acts as a chamber to contain the air inside. 8 Small narrow slots on the stator allow the sound to come out. The sound is then projected by 8 large fiberglass horns. It consists of a belt driven Paxton blower, that uses a 10 Hp TEFC motor. The rotor is 9.75 inches in diameter and has 5 ports. Including the stator it is in total 11.75 inches in diameter. The rotor is powered by a 2 Hp TEFC motor that spins at 3600 RPM. By 6/10/2004, the plant was discussing a system replacement project due to saying the current system is "aging", and a year later starting In November 2005, (a month after the annual siren test), the Model 120s and the STL-10s started to be gradually removed and replaced, and by Febuary 2006 all have been replaced marking October 26th, 2005 as the final test of the original system, as well as the end of the one of a kind original system that stood out from all other Nuclear plant systems. Whelen WPS 2810s and WPS 2806s were installed in their places. The 2810s went in place of the Model 120s and the 2806s went in place of the STL-10s. These new electronic sirens have battery backup, are more efficient, less maintenance, and having similar ranges to the original system such as the 2806s having better range compared to the STL-10s, and the 2810s having close to the same range but about 2,000 feet less range compared to the the Model 120, but still enough range to cover the EPZ, and as for the strict requirements of the original system, that was no longer an issue as by the 2000s there was commercially produced omnidirectional sirens that have close to the same range as the Model 120 and as well have better range then the STL-10s. After all the old sirens have been removed and replaced, SONGS sold 23 of the STL-10s to Curry County Oregon to be used as tsunami sirens, and the Model 120s and remaining 5 STL-10s are believed to have been scrapped, but its unknown if they were, or went somewhere else but hasn't been discovered. The only Model 120 that is known and remaining is in the possession of Aaron Allevato (Duderocks5539) and Edaan Friedman and currently under restoration to be brought back into operating condition.
Siren patent: https://patents.google.com/patent/US4649853
