# Presentation: 683792

## Reliability & Maintenance

- Paul C. Czarapata

## Maintenance Time

- The following chart represents the amount of time spent on maintenance during a 168 hour week.  IT DOES NOT REPRESENT TOTAL DOWNTIME.  Some periods overlap each other where the chart treats them linearly.  It also does not represent availability for the same reason.

## Slide 3

## Status Update

- Items Presented to DOE review
- Voltage to Frequency Converters
- Part of Quench Protection System in Tevatron
- Plan called for replacement of Low Beta House Systems
- All cards replaced, All crates replaced, All sense resistors modified.
- Plan expanded to include all VFC’s in Tevatron

## Status – cont. 2

- Overhaul Cryogenics Wet Engines
- All overhauls are complete and should take us comfortably into the summer shutdown.
- Cold Compressor Bearings
- We have located an alternate source.
- We have enough on hand but additional units are going to be ordered this FY.

## Status – cont. 3

- Compressor Starters
- Plan is to replace 2/3 this Fiscal Year 1/3 next year
- First 1/3 are complete.
- Second 1/3 will be done in Summer shutdown
- Remainder will be ordered after October.

## Status – cont. 4

- Other items are in process and showing good progress.  We have handled the majority of the “critical” items.

## Current Mysteries

- Ground Motion
- Traced to Domestic water well #1
- Magnet Motion
- Traced to “bad” Tevatron magnet stands
- Kicker Pre-fires
- Company says “you have the best pre-fire rate of anyone using this configuration”

## Motion in MI-8 line

## Newest Dilema

- Magnet Stands are rusting away.
- Evidence of motion with Humidity (rust jacking)
- Evidence of motion with high current in magnets
- (weebolls wobble but they don’t fall down!)
- Ed. Note weebolls were round bottom toys for small kids.

## Tev Dipole Roll vs. I

## Magnet motion vs. Quench and humidity

## Magnet Stand in A16

## Replacement of Stands

- During the January shutdown we successfully replaced the A16-3 stand while the magnet was at nitrogen temperatures.  The total number of stands needing replacement is now being cataloged for replacement when time is available.
- We have placed additional tilt monitors in the Tevatron

## And still more!

- Linac Power Tubes
- Use ~ 7 per year
- This was based on 10,000 hr lifetime (typical)
- Have had two failures after 2,000 hrs.
- Compete with other labs for tubes
- Military no longer uses this tube so volume is down for vendor.
- Thoriated cathodes were changed from 2% to 1.5% due to OSHA difficulties.

## Linac Tubes –cont.

- Coming out of the January shutdown we had a tube that was believed to be only marginally useful (25%).
- Two tubes due in February.  Vendor says we will get 1 per month between now and August. We currently have Argonne’s spare installed.

## Vulnerabilities

- A list of items (vulnerabilities) was generated August of ’02.
- These items would keep the lab down for at least 3 months should they fail.
- The list was prioritized by likelihood and forwarded to DOE by Steve Holmes.
- The list represented ~ $28.7M just in equipment.

## Summary

- We continue to battle an aging infrastructure for the machine components.
- We will need high reliability and availability to meet the laboratories aggressive running schedule.
- We will need increased funding to stay ahead of the problems.