Stroke time measurements 1

[ICRH]

Due to our recent beginning in diagnostic testing on AOVs we have some questions about if we are trying to go too far in the data acquistion. This is particularly important in the case of the 'stroke times'. The questions are:

1.- Is Diagnostic Testing used to take measures of the stroke times? If so,
1.1- What are the times you used to compare to? New reference times?
1.2- Do you take solenoids, limit switches signals?
2.- Do you use a rigid procedure to identify the specific position and tolerance to mount the limit switches on the AOV? If so,
2.1- Is it valve or travel valve dependent?
2.2- How do you test the limit switches act in the desired position?

Any experience will be very wellcome.

 

[cloa]

Which AOV?

http://acronyms.thefreedictionary.com/AOV

How is it nuclear engineering?

 

[ICRH]

Air Operated Valve -> AOV

 

[vpl]

ICRH

Some more information would be helpful. I think everyone reading the post (far more than just cloa) understood the accronym AOV), athough generally you're right it's better to spell them out then to use them.

If you'e in the US, then my answer would be: no, diagnostic testing is not normally done for stroke time testing. However, that doesn't mean that diagnostic testing isn't done. It's just that it's done for different reasons.

Stroke time testing is normally done to show that the valve can meet its design basis function to open or close for accident analysis, usually specified in your final safety analysis report or technical specifications (again this is based on US terminology).

There is usually a test procedure (required in the US for safety related valves) with appopriate test margins to ensure that the valve will perform when needed. Some valves must both open and close, some only have to open, some only have to close.

Yes, the limit switches and solenoids need to be included.

If you're not in the US, then the regulations in your country would need to apply.

Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[ICRH]

VPL
Though I am in Europe, our regulations and procedures are following yours and then are almost identical.

Yes, we have been doing stroke time testing for a long time, tipically measuring times from the control room based on lights.

Here, we started doing diagnostic testing because of the JOG AOV program.
Now, what happens is that we might be trying to get more benefits than stablished in the beginning, by doing specific tests to measure stroke times, reading the point in which the solenoids and the limit switches act, ...
As a result we observed that the position in which the limit switches (tipically NAMCO) act has an excessive variation.

Our main concerns, and the reason for the previous questions, are:
- Assure the correct position of the limit switches. Any detailed procedure to mount the limit switches?
- Simplify the objectives of the diagnostic testing. Taking apart the concerns about the stroking times.

Thans

 

[vpl]

ICRH

Since I don't work at a utility, I don't have access to any detailed procedures for limit switch setting or air operated valve dianostic testing. I do know they exist. If your utility is a member of an owners group (such as the Westinghouse owners group), you might be able to get a copy of a procedure through them.

You might also try working through the Institute of Nuclear Power Operations (INPO) or the Nuclear Energy Institute (NEI) to find a US utility that would be willing to share detailed procedures with you.

Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.