Steam generator tube plugging.

[mostlyharmless]

Has anyone ever covered tube plugging using a small explosive charge? I heard a tech taklking about this and do not know if it is a real technique. I believe he used the term shock ping or plug.

[Marlin]

It was real, but I have not heard of it being used since the late 70s.

[Mike McFarlin]

We tried to video the flame coming out of the manway. It blew the camera over. A long time ago......

[mostlyharmless]

Incredable. By the time I came along it was rosa and roger.

[retired nuke]

Has anyone ever covered tube plugging using a small explosive charge? I heard a tech taklking about this and do not know if it is a real technique. I believe he used the term shock ping or plug.

That was my first nuke job - jumper installig the plugs - 3 at a time, tented platforms, very old school...

[UncaBuffalo]

Has anyone ever covered tube plugging using a small explosive charge? I heard a tech taklking about this and do not know if it is a real technique. I believe he used the term shock ping or plug.

They tried explosive sleeving at Trojan circa '91...obviously not very successfully...




Note:  It is possible to decon a dud explosive sleeve.  Only time I've seen someone deconning with that strong of acid, but...took the contaminated layer right off...

[Mike McFarlin]

 Author Topic
MIA
Guest
(No subject)
« Sent to: Mike McFarlin on: Today at 06:38:49 PM » Reply with quote Remove  

--------------------------------------------------------------------------------
Mike, I do not want to hurt your feelings but you are full of s--t.




Another non-believer! Guess you had to be there ducking behind the bio-wall.

[Adam Grundleger]

It's a real procedure.  I haven't seen it done, but explosive welding of heat exchanger plugs and sleeves are still listed as repair techniques in ASME Section XI. 

If they ever do it here (Wolf Creek) I'm definately going to set it as a hold point. 

[RDTroja]

Wow... I guess I really am getting old. I covered more explosive tube plugging operations than I can count, up into the early eighties.

You took a maximum of 3 explosive charges (1/3 stick of dynamite equivalent each) that looked like long shotgun shells with wires coming out where the firing pin would normally hit and had to space them properly (X number of rows apart) within the tube sheet. The locking mechanism (at least on the ones I saw and that caused the following story) was an over-center 'Cam-Lock' device that you turned after inserting the plug up into the tube.

At a Northeast nuclear plant that will remain nameless here (I have been saying that a bit lately) there was an incident in 1978 where a Boilermaker with, well... let's just say less experience than required, was told to insert the charges into the marked tubes and turn the locking mechanism 180^o to lock it in place. Unfortunately this Boilermaker was not fully educated in mathematics and when he felt the resistance at 90^o he figured the plug was locked. It wasn't. As a matter of fact he did it three times and none of them were locked. After he exited the channel head we placed the blast cover in place (a 'recent' invention at the time) and in the process must have tugged on the three lead wires just enough to pull them down from the tubes into the channel head... where they laid in the bottom, all apparently sitting together. We all exited the immediate blast area and retreated behind the bioshield.

At this point I should tell you that this was about the fifth or sixth set of charges we had set off in a series of a few days, so it was getting pretty 'routine' if you can actually apply that term to what we were doing, which in retrospect still amazes me. The demolitions guy had even let me set off the charges a couple of times. Very cool. Actually got to say 'Fire in the Hole' and push the little handle down. Normally there would be a muffled 'Boof' kind of noise since the charges were inside the tubes and the blast cover and HEPA filter masked the sound. But not this time.

"Booooom... Clang, bang, clang, crash (and a few more choice noises.) We all looked at each other through our respirator facepieces and all you could see was eyes... seriously it looked like a Warner Brothers cartoon. I peered around the corner and saw smoke billowing out of the steam generator bowl... at least that is what I thought it was. Actually it was the dried out contents of the bowl turned into a very fine dust. (The manway cover interior surface was ~6 REM/Hr gamma and It-doesn't-matter-how-much Beta and the Tube sheet was 40 REM/hr with an Ion Chamber instrument.) There was the blast cover on the floor (about 12 to 15 feet below the nozzle, IIRC) which had caused most of the noise after the 'Booooom' part.

My finely honed HP instincts at this moment could think of nothing but 'We're outta here' and looking back they were right on target. Unfortunately our Site Coordinator had taken this particular opportunity to witness his first explosive tube plugging and was tapping me on the shoulder at that very minute saying 'Air Sample' to which I replied "No. We gotta go!" and he said "If we leave without an air sample we have to come back in with Scott Air Packs to recover." Now, this was my first job with this company, and I was young and eager to please my new boss, so I ignored my better judgement (turns out it was better than his, too) and I got the air sample. My brother, who was my junior tech assistant at the time, told me I disappeared into the cloud that was still billowing out of the manway as I climbed the ladder. The 5 minute, 2 CFM particulate sample (it was the only sampler we had set up at the time) read over 200 mR/Hr GAMMA. It could not even go into the count room.

After some classic HP voodoo and radcon math number crunching, I was credited with 100 MPC hours (roughly the same as today's DAC-Hrs) for the five minutes I was in the cloud, counting the 50 protection factor for the 'canned ham' style filter respirator I had on. I later found out through experimentation that about 10% of those old filters failed right out of the box... which is where I had gotten mine. I went right to the shower and then to the body counter where I was declared 'clean.'

Naturally, the next crew to go to the area had to go in Scott Air Packs anyway, so all we gained from the air sample was an ending to the story.

Yes, Virginia, there was such a thing as Explosive Tube Plugging. Which leads to the story where I thought I had been blown up...

[Frankie Love]

Ah...what a great story. I miss the "old" days...

[Already Gone]

"old days"  That wasn't so long ago.  Actually, the explosive sleeve welding was my last experience with sleeve and plug installation.  Before that, there were lots of welding rigs, but none were as fast and effective as the "kinetic weld process".

I never witnessed a cloud of contamination such as Roger described, but the tube cleaning and honing that they did to prep the tubes for the weld did pose some problems. 

[Rennhack]

"old days"  That wasn't so long ago. 

Troy, "up into the early eighties" is about 30 years ago.  That IS a long time, you old fart.

[Jr8black3]

RD Karma to ya, to cover that job it took alot..

I can remember cleaning up the messes in the 80's the jumpers would leave for us deconners back then,, CY had to be the worse ANO was bad back in the 80's too,, Cook would have been ok,, but jeez the platforms were so small back then you had a hard time getting out of the shine..

Living a better life now..

[spentfuel]

Wow... I guess I really am getting old. I covered more explosive tube plugging operations than I can count, up into the early eighties.

You took a maximum of 3 explosive charges (1/3 stick of dynamite equivalent each) that looked like long shotgun shells with wires coming out where the firing pin would normally hit and had to space them properly (X number of rows apart) within the tube sheet. The locking mechanism (at least on the ones I saw and that caused the following story) was an over-center 'Cam-Lock' device that you turned after inserting the plug up into the tube.

At a Northeast nuclear plant that will remain nameless here (I have been saying that a bit lately) there was an incident in 1978 where a Boilermaker with, well... let's just say less experience than required, was told to insert the charges into the marked tubes and turn the locking mechanism 180^o to lock it in place. Unfortunately this Boilermaker was not fully educated in mathematics and when he felt the resistance at 90^o he figured the plug was locked. It wasn't. As a matter of fact he did it three times and none of them were locked. After he exited the channel head we placed the blast cover in place (a 'recent' invention at the time) and in the process must have tugged on the three lead wires just enough to pull them down from the tubes into the channel head... where they laid in the bottom, all apparently sitting together. We all exited the immediate blast area and retreated behind the bioshield.

At this point I should tell you that this was about the fifth or sixth set of charges we had set off in a series of a few days, so it was getting pretty 'routine' if you can actually apply that term to what we were doing, which in retrospect still amazes me. The demolitions guy had even let me set off the charges a couple of times. Very cool. Actually got to say 'Fire in the Hole' and push the little handle down. Normally there would be a muffled 'Boof' kind of noise since the charges were inside the tubes and the blast cover and HEPA filter masked the sound. But not this time.

"Booooom... Clang, bang, clang, crash (and a few more choice noises.) We all looked at each other through our respirator facepieces and all you could see was eyes... seriously it looked like a Warner Brothers cartoon. I peered around the corner and saw smoke billowing out of the steam generator bowl... at least that is what I thought it was. Actually it was the dried out contents of the bowl turned into a very fine dust. (The manway cover interior surface was ~6 REM gamma and It-doesn't-matter-how-much Beta and the Tube sheet was 40 R/hr with an Ion Chamber instrument.) There was the blast cover on the floor (about 12 to 15 feet below the nozzle, IIRC) which had caused most of the noise after the 'Booooom' part.

My finely honed HP instincts at this moment could think of nothing but 'We're outta here' and looking back they were right on target. Unfortunately our Site Coordinator and taken this particular opportunity to witness his first explosive tube plugging and was tapping me on the shoulder at that very minute saying 'Air Sample' to which I replied "No. We gotta go!" and he said "If we leave without an air sample we have to come back in with Scott Air Packs to recover." Now, this was my first job with this company, and I was young and eager to please my new boss, so I ignored my better judgement (turns out it was better than his, too) and I got the air sample. My brother, who was my junior tech assistant at the time, told me I disappeared into the cloud that was still billowing out of the manway as I climbed the ladder. The 5 minute, 2 CFM particulate sample (it was the only sampler we had set up at the time) read over 200 mR/Hr GAMMA. It could not even go into the count room.

After some classic HP voodoo and radcon math number crunching, I was credited with 100 MPC hours (roughly the same as today's DAC-Hrs) for the five minutes I was in the cloud, counting the 50 protection factor for the 'canned ham' style filter respirator I had on. I later found out through experimentation that about 10% of those old filters failed right out of the box... which is where I had gotten mine. I went right to the shower and then to the body counter where I was declared 'clean.'

Naturally, the next crew to go to the area had to go in Scott Air Packs anyway, so all we gained form the air sample was an ending to the story.

Yes, Virginia, there was such a thing as Explosive Tube Plugging. Which leads to the story where I thought I had been blown up...

seems I also worked this un-named plant the next outage or two....

I remember asking "why the h__l does it take doubles and a half face to enter the bio shield ?" 

Then I found out.  Ill add part of what I heard is that the blast bag was destroyed and it was one of the few if not the only one on site so they made the megawatt fever decision to continue plugging without bags.

I also recall doing a RWP survey to determine why a valve crew was burning on each entry.  As I climbed to the area below the regen heat exchanger I found a Rad sign hanging in the middle of nowhere facing the other way.  Much to my surprise when I flipped it over to read it "Hot spot stay away 300000 mr/hr" .  Would have been good info up front 

But I did get to update the sign to excess of 800000 mr/hr

yep the good old days 

sf

[UncaBuffalo]

"old days"  That wasn't so long ago.  Actually, the explosive sleeve welding was my last experience with sleeve and plug installation.  Before that, there were lots of welding rigs, but none were as fast and effective as the "kinetic weld process".

I never witnessed a cloud of contamination such as Roger described, but the tube cleaning and honing that they did to prep the tubes for the weld did pose some problems. 

...like if you put your HIC on the refuel floor...and (not once, but twice) drop 50R/hr spent honing filters back to the basement?


                                 (-8 air OUTSIDE containment WILL result!)

[Jr8black3]

Well that sucks,, but we are off topic, I know you guys seen some nasty chit as well as I have,, And I repect for ya brothers and sisters,, Worst job I ever had was at WNP-2,, 900mr every ten minutes,, job had to be done and it was a pain in the ass...

But we are way off topic

[Already Gone]

seems I also worked this un-named plant the next outage or two....

I remember asking "why the h__l does it take doubles and a half face to enter the bio shield ?" 

Then I found out.  Ill add part of what I heard is that the blast bag was destroyed and it was one of the few if not the only one on site so they made the megawatt fever decision to continue plugging without bags.

I also recall doing a RWP survey to determine why a valve crew was burning on each entry.  As I climbed to the area below the regen heat exchanger I found a Rad sign hanging in the middle of nowhere facing the other way.  Much to my surprise when I flipped it over to read it "Hot spot stay away 300000 mr/hr" .  Would have been good info up front 

But I did get to update the sign to excess of 800000 mr/hr

yep the good old days 

sf

This place sounds an awful lot like the one I will not name (it's initials are IP-2) where I was baptized by fire right off the boat.  Explosive tube plugging would not have raised a blip on the radar of that place.

[mostlyharmless]

Inside the generators at CY was my first job: the platforms were very small. It was the first time I has ever seen an epd. It flashed faster and faster as I climbed the ladder. I climbed back down and told the hp " hey this things flashing like hell is it supposed to?" He said "
its working fine get back up there". So I did. Completely clueless.The explosion and the cloud belching from the genny. I don't know. I probably would have gone in too. Thanks for the story.

[RDTroja]

This place sounds an awful lot like the one I will not name (it's initials are IP-2) where I was baptized by fire right off the boat.  Explosive tube plugging would not have raised a blip on the radar of that place.

[Laundry Man]

Maine Yankee back in the late 70s was the last place I experienced this method of plugging.  When I got to IP-2 (after the flood), it was mechanical plugging after installing the templates.
LM

[jjack50]

They tried explosive sleeving at Trojan circa '91...obviously not very successfully...




Note:  It is possible to decon a dud explosive sleeve.  Only time I've seen someone deconning with that strong of acid, but...took the contaminated layer right off...

It is my recollection that the explosive sleeving was successful at Trojan. What failed was that each tube that had beed sleeved needed to be heat treated following the explosion. One of the tubes at Trojan was not heat treated. That lead to the tube failure during the following cycle.
Security spent a lot of time counting charges...

[UncaBuffalo]

It is my recollection that the explosive sleeving was successful at Trojan. What failed was that each tube that had beed sleeved needed to be heat treated following the explosion. One of the tubes at Trojan was not heat treated. That lead to the tube failure during the following cycle.

Tomayto/Tomahto




...one of those 'the-operation-was-a-big-success-but-the-patient-died' scenarios...

[UncaBuffalo]

Has anyone ever covered tube plugging using a small explosive charge? I heard a tech talking about this and do not know if it is a real technique. I believe he used the term shock ping or plug.

Could you have been hearing 'shot-peen'?  That was another Voodoo technique that was used to (supposedly) extend the life of Westinghouse steam generators.  We basically sand-blasted the inside of all the tubes with small 'shot'...theory was (as I remember it) that the pressure applied by the 'shot-peen' would help re-align the molecules and prevent the stress cracking of the tubes...?  

Anyway, as with explosive sleeving, the problems continued & all the S/G's have had to be replaced...or, in Trojan's case, the S/G issues led/contributed to the whole plant being D&D'd...  

[Already Gone]

You are correct.  Shot peening is a means of mechanical stress relief.  It does not involve explosives.