NRC Event Report SCRAM Code help

[Northmeadow]

TL;DR Summary

Need help understanding the NRC event report SCRAM Code letters meaning.

I am a dedicated nuclear physics and radiology enthusiast who often looks at the NRC’s event notification reports for information about our countries nuclear industry and the status of our reactors. And every time I read the report and an event occurs at a commercial reactor they are required to provide key details about the reactors current status and its status at the time of the event.

Most of the time this information is very easy to understand and interpret. Such as the unit number (1,2,etc.), the initial power and current power level (0-100) along with wether the reactor was critical or not and still is (Y, N) and what operating condition the reactor was in and is in now (Power Operation, Hot Standby, Cold Shutdown). But one parameter they display is called SCRAM Code and which include N, M, E, A, R and a couple of other letters I have seen. However I can not find a single document that explains what these letters mean.

I have searched all of the NRC’s document stores along with everywhere else on the web I can think of. Now I do have a couple guesses as to what they mean such as “N” being “No”, “M” being “Manual”, “E” being “Emergency and “A” being “Automatic”. But I am really hoping someone here can either point me in the right direction or can explain them to me, so I know exactly what each code means.

If you would like to read these reports and get a feel for what I am talking about you can find them here. The photo below is a screenshot of one of the event report with the parameters I spoke about for clarity.

Thank you in advance!

 

[gleem]

I am familiar with some of the NRC regs particularly those related to radiation exposure and medical uses of byproduct material. It is sometimes difficult to find a particular item without going through the whole relevant parts of Title 10 Code of Federal Regulations of which there are about 55 including numerous subparts and multitudinous sections. I expect that the codes you seek the meaning of are reference somewhere in the regs relative to nuclear power reactors Parts 50 and up. Sometimes the NRC writes guidance documents or references documents from other advisory groups to help licensees better comply with the regs. WRT to scram codes, check this out

https://www.nrc.gov/docs/ML1232/ML12326A805.pdf.

It does seem to discuss a classifications scheme for reportable events.

 

[Astronuc]

There used to be instructions for Event Notification Reports, but I can't find them. Note that the 'SCRAM Code' is part of the template for power reactors, so there has to be an entry.

https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2008/20081222en.html#en44735 (A/R)
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2008/20081222en.html#en44736 (M/R)
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2008/20081222en.html#en44737 (N)
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2008/20081222en.html#en44738 (N)

From the 3 examples on the same day. N = No SCRAM (or not applicable), M/R = Manual Reactor Scram/Trip, A/R = Automatic Reactor Scram/Trip.

https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2011/20110418en.html#en46761 (A/R)
On April 16, 2011, a tornado touched down in the (Surry) plant's electrical switching station, disabling primary power to the plant's cooling pumps and causing the backup diesel generators to activate without incident.

North Anna tripped, but Surry did not in response to an earthquake near North Anna site
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2011/20110824en.html#en47181 (A/R)
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2011/20110824en.html#en47189 (N)

At North Anna and Emergency Class: ALERT 10 CFR Section: 50.72(a) (1) (i) - EMERGENCY DECLARED,
ALERT DECLARED DUE TO AN EARTHQUAKE IN THE AREA AND A LOSS OF OFFSITE POWER
Not so at other plants on the same page.

 

[Northmeadow]

Thank you @gleem and @Astronuc! I knew it had to be something relatively simple. I just couldn’t for the life of me find any of the documentation. I think the NRC needs to work on their databases fuzzy search capabilities or at least ensure all documentation is present!

again thank you!