steam generator primary side surveys

[grantime]

We currently use a RO-7 to survey primary side s/g.  We survey for both beta and gamma levels.  These meters are old and tend to fail at the worst possible times(Generally about half way through the intial survey).   I have several questions:

1) Do you survey for beta dose rates on tubesheets and divider plates?  If your plant doesn't then how do you "provide adaquate surveys" if you don't have any current data.  Or does INPO/NRC show an interest in this issue?

2)Is there a better choice for meters? Ideally an ion chamber type instrument with a remote detector.  Almost anything is better than the suggestion I got to put 2 Ro-2's (one open window and one closed) on a stick and use it to survey area.

[Already Gone]

When the diaphragms come out, before they get deconned, take them to a low-doserate area (relatively low - don't get silly) and do a beta and gamma survey on them.  You can use the same ratio of beta/gamma for the tubesheets, since the isotopic component of the source material will be identical.
For the tubesheet survey, I'd use an AMP-100 on a stick or a good extendable instrument.  There are lots of durable high-range instruments that you can put on one of those telescoping handles (like the one for your swimming pool tools) for this survey.
Don't spend a lot of time and money on this.  Making jumps into the channel heads will soon be another memory.  It is no longer necessary to jump to install nozzle dams.  Of course, you'll always want to be prepared for the contingency of an un-planned jump.  In that case, you can get the vendor (Areva, Westinghouse, or whoever) to make a tool to fit on their robot for holding instruments.  If you ask nice, they'll even do the survey with you from their control room.  You get the platform worker to attach the probe to the robot, have the operator put it in whatever place you want the doserate, with a long enough cord, you can take the readings while sitting at the HP desk. 

[retired nuke]

Whatever happened to the good old days when we would put 8-10 tlds on a stick, and put them into the bowl for a timed period, then read them next shift. I think 2 of us did both sides of all 4 SG at Salem for under 100 mR. Got good numbers too - able to measure actual attenuation from PCs etc by wrapping the tlds in different material.

Now everyone wants survey data 15 minutes after the manways come off......

[grantime]

We used to do the survey with TLD's.  That was when we read them on site.  I agree that they are the best way to do the survey but now realistically now the window for whole S/G work is about the same as time to get results back.  That is worse than useless.  At least for us...

[SloGlo]

iffen beercourts answer ain't to yer liking, do a survey jump 'n take yer dose rates, smears, 'n whatever else the upstairs wants.

[grantime]

I like beercourts idea especially because otherwise it will probably be me doing the jumping.  And I don't want to see which is bigger around-- me or the manway....It all depends on what I can convince the bosses(plural)  to do.

Is anyone out there doing direct beta dose rates of tube sheets and bowl anymore? 

[RAD-GHOST]

Is anyone out there doing direct beta dose rates of tube sheets and bowl anymore?

Maybe one, for S*#ts & Grin's!

It is no longer necessary to jump to install nozzle dams.  Beercourt, who has that and how is it done?

S/G Survey Tips:

1) The silver shinny side of the Diaphragm is not the side your interested in.

2) If your highest smear from the diaphragm is 10K, you smeared the wrong side!

3) SMEARS: Check them with your meter and DON'T put them in your pocket!

4) A spare meter, with you, isn't a bad idea.

5) If you leave all your equipment behind because it's highly contaminated, when you go back it will highly contaminated and highly broken!

If this seems rather juvenile, but I typed it for a reason!

RG

[retired nuke]

Rad-Ghost

Well put, good lessons for anyone that hasn't done it, good reminder for those of us that have.

Karma to ya...

[Already Gone]

It is no longer necessary to jump to install nozzle dams.  Beercourt, who has that and how is it done?

Westinghouse puts them in with a robot.  Areva will most likely be following suit.

5) If you leave all your equipment behind because it's highly contaminated, when you go back it will highly contaminated and highly broken!

HAH!!! I love that one!!

[grantime]

My understand is that westinghouse will be jumping to install ours.  I don't think we bought the deluxe package.  The good news is that our S/G are still fairly new and dose rates have been on the order of 1 rem/hr contact with tube sheet.  A big change from our old ones in the 20 R/hr range. 

[wlrun3@aol.com]

INSTALLING NOZZLE DAMS 100% REMOTELY

Remote installation of nozzle dams in PWR steam generators is now a well established technique, with substantial man-rem savings.

Nozzle dams are used to isolate the primary channel head of a steam generator from the primary loop during refueling outages. This allows work to be carried out in parallel on the steam generator primary side and on the refueling canal - with consequent savings in outage duration.

The nozzle dam can be installed using either Brand's ROMA (Remotely Operated Manipulator Arm) robot or Westinghouse's ROSA III robotic system, promising significant reductions in personnel exposure. With the ROMA option, a multi-purpose delivery system, with winch and three remotely operated cameras and halogen lights, positions the ROMA six-axis hydraulic robot arm inside the steam generator. The operator then installs the entire nozzle dam remotely from the control center. He uses a remote master controller, which is a scale replica of the ROMA arm.

Field experience to date with ROMA for nozzle dam operations is as follows: 1990 - Catawba 2 (nozzle dam removal), 1991 - Salem (nozzle dam installation and remote welding), Trojan (nozzle dam installation, removal and remote welding), Catawba 2 (nozzle dam installation and removal), Catawba 1 (nozzle dam installation and remote welding).

The first application of ROSA III - the universal robotic steam generator maintenance tool - for installation and removal of the Brand nozzle dam was at Farley 1 in autumn of 1992.

With the ever increasing emphasis on dose reduction and the need to eliminate manned channel head entry, remote installation of nozzle dams is set to become the industry norm in the coming years.

For more, "Installing Nozzle Dams 100% Remotely," Nuclear Engineering International, pp. 17-19, March 1994.

[RAD-GHOST]

...................and apparently for some time!  I've been running a circuit on the edge of technology, the trailing edge!

Good Info, Thanks, RG

[Mike McFarlin]

What will they think of next?

[SloGlo]

What will they think of next?

probly sum lifting rig with a track mekanism for mooving da spent fool aroun

[Old HP]

I am going out on a limb and agreeing with Beer Court on the beta issue. The diaphram can tell a lot about the steam generator. I started  using TLD tree surveys at Trojan in 1979. My favorite way to survey, but as  mentioned earlier "manways are off, lets get this outage over" has become the norm.
Thirty years of covering steam generators and I can safely say I have never met a steam generator I liked.
In regard to the survey info the conservative approach is  dose rate the diaphram (beta & gamma, and a smear for isotopics, then 8-12 dose rates and repeat with a second meter. The only variable is what kind of surprise you can find in the bottom of the bowl.

[grantime]

Suprises are not generally a good thing. 

[wlrun3@aol.com]

 


From: WlRun3@aol.com [mailto:WlRun3@aol.com]
Sent: Thursday, February 08, 2007 12:32
To: ndjob@radiuminc.com
Subject: Roadtechs.com post: Steam Generator Technicians - No Experience Necessary!!


...roughly what percentage of pwr's install nozzle dams remotely (without actually fully entering the channel head)...thought i would ask the pros...thankyou


...email reply... "Zero. It was  done in the early 90's but it was not cost effective...too much critical path time used and the high cost of equipment and labor pushed it back to just manual installs."

[Limited Quanity]

We currently use a RO-7 to survey primary side s/g.  We survey for both beta and gamma levels.  These meters are old and tend to fail at the worst possible times(Generally about half way through the intial survey).   I have several questions:

1) Do you survey for beta dose rates on tubesheets and divider plates?  If your plant doesn't then how do you "provide adaquate surveys" if you don't have any current data.  Or does INPO/NRC show an interest in this issue?

2)Is there a better choice for meters? Ideally an ion chamber type instrument with a remote detector.  Almost anything is better than the suggestion I got to put 2 Ro-2's (one open window and one closed) on a stick and use it to survey area.

We still use the RO-7 too.  Set them up as a set, one o/w and the other c/w.  Takes two teams of two RP's to do all the surveys, 7 points in each bowl, & on 4 S/G's.  One's on the stick at the manway and the other on the platform reading the doserates back to the camera room.  We keep a backup set of 7's at the entrance to the playpen incase one of the two craps out during the survey.  I remember using the tld trees years ago but that went away with the non-existent term called "time pressure" that doesn't exist anymore  

We still jump to manually install our dams.  Our employees do it.  Most are managers or wantabees.  Saves them abunch of money though.  They used to get a shirt and a Walmart card but that went away too.  Nothing like sticking the site VP in the showers.  They tend to remember you when the hot water heater runs out.  One of those things he didn't have money in the budget to fix.

Can't help on the new age technology with instruments.  I'm just tickled to death when my RO2A gets back from the body shop and all the dents are popped out!

[JessJen]

I'm just tickled to death when my RO2A gets back from the body shop and all the dents are popped out!

but but but those give it character

[UncaBuffalo]

It appears they have discontinued the venerable R0-7.    I always had good luck with these...esp. for U/W work.

Now Thermo is pushing something called the E600...anyone have any experience with them?

[RDTroja]

BeerCourt hit the nail on the head (once again). Once you know your Beta/Gamma ratio you are home free and can use any gamma instrument to do the rest of the survey. I used that technique at Indian Point 2 in 1978 and learned all about Strontium-90 and what a truly hard beta was (not to mention how pig-headed some utility people can be when you try to tell them they now have an alpha problem, too).