ML17058B522
| ML17058B522 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/23/1991 |
| From: | NRC - INCIDENT INVESTIGATION TEAM |
| To: | |
| Shared Package | |
| ML17056C371 | List:
|
| References | |
| CON-IIT07-120A-91, CON-IIT07-120B-91, CON-IIT7-120A-91, CON-IIT7-120B-91 NUREG-1455, NUDOCS 9305060267 | |
| Download: ML17058B522 (52) | |
Text
oRielNAIL OFFICIALTRANSCRIPT OF PROCEEDINGS Agency:
Title:
Nuclear Regulatory Commission Incident Investigation Team Nine Mile Point Nuclear Power Plant Interview oP:
PERRY
~ERTSCH Docket No.
- Scriba, New York
- Friday, August 23, 1991 PAt;ES.
1 10 AI'&RILEY&ASSOCIATES, LTD.
1612 KSt. N.W:, Suite 300 Washinyon, D.C. 20006 (202) 293-3950.
9305060267 9ii03i
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1
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION INCIDENT INVESTIGATION TEAM 6
Interview of 7
PERRY BERTSCH 8
(Closed) 10 12 13 14 15 16 17 18 Conference Room B
Administration Building Nine Mile Point Nuclear Power Plant, Unit Two Lake Road
- Scriba, New York 13093 Friday, August 23, 1991 19 The interview commenced, pursuant to notice, 20 at 1:10 p.m.
21 22 23 24 25 PRESENT FOR THE IIT:
Frank Ashe, NRC Jim Stoner,
- Duke, NRC
P R 0 C
E E
D I N G
S
[2:08 p.m.]
MR. ASHE:
My name is Frank Ashe and I'm a member 4
of the Incident Investigation Team being -- as a
5 participant.
I have today, Mr. Perry Bertsch who is in the 6
instrumentation and control department and we would like to 7
record some information from him.
- Perry, could you go over and give us some of your 9
background and history with the station in terms of your 10 work activities and how long you'e been employed here?
MR.
BERTSCH: I'e been with Niagara Mohawk since 12 October of 1983.
And I came in as a technician in the I&C 13 department.
And I'e been here through most of the startup 14 and I'e worked on these units and various other equipment 15 in the plant during that time.
16 MR. ASHE:
Okay.
When you say worked on this 17 equipment, could you explain--
18 MR.
BERTSCH:
Yes.
On uninterruptable power 19 supplies, all the ones we have on site, or at least the ones 20 that are in the plant and all sorts of other equipment.
21 MR.
ASHE:
Could you give us some of your work 22 activities, specifics of some of your work activities?
23 MR.
BERTSCH:
During start-up, initial testing, 24 calibration of valves and control circuits and control cards 25 and start-up and maintenance functions on the -- on the
3 1
uninterruptable power supplies, maintenance on redundant 2
reactivity control system, trouble shooting repair, doing 3
various surveillance tests on the various instrumentation 4
that we have in the plant.
MR. ASHE:
Okay.
In terms of the UPS that failed 6
during the event, had you previously worked on this 7
equipment?
MR.
BERTSCH:
Yes.
MR.
ASHE:
What were some of your activities with 10 regard to working on these items?
MR.
BERTSCH:
Initial start of initial testing, 12 doing the acceptance tests on the units, and then various 13 preventive maintenance along the way, various corrective 14 maintenance, you know, trouble shooting if something goes 15 wrong, assisting operators and training them on how to do 16 various things on the units.
If the unit fails actually 17 going through there, you know, tuning down component level 18 replacement or fuses or whatever else.
Normally various 19 things like that with electrical maintenance.
20 MR.
ASHE:
Were you involved with the recovery of 21 the units following their failure?
22 23 MR.
BERTSCH:
Yes.
MR.
ASHE:
Could you, as best you could, recall, 24 explain your involvement and the activities that you 25 participated in?
4 1
MR.
BERTSCH:
I was a member of damage control 2
team three and we went down there to attempt to restart the 3
five Exide units.
We went down and then -- let's see 4
reset the trips, closed the breakers in and restarted the 5
I forgot the order in which we started them up in.
I 6
believe it was 1C -- started up the unit, transferred over 7
to UPS, found there wasn't any type of problem with the unit 8
in itself as far as startup or anything.
Started up or 9
attempted to start all five units.
10 We found when we closed in CB-1 on 1A, we found we 11 tripped the switch gear breaker twice so we didn't do 12 anything with that and 1-Bravo we couldn't restore to 13 service because CB-3 wouldn't close.
I put the other units 14
-- 1-Charlie, 1-Delta and 1-Gulf were returned to service.
15 MR.
ASHE:
Do you have an opinion as to what may 16 have occurred with the units?
17 18 19 MR.
BERTSCH:
At the time of the event, no.
MR.
ASHE:
At the time of the event?
MR.
BERTSCH:
At the time of the event, no.
20 Because I had no knowledge of, you know, all what had 21 transcribed, you know, prior to that.
We heard we had 22 problems in the plant, but not as far as, you know, what 23 would have contributed to all the units going away.
24 MR.
ASHE:
Based on your knowledge today, would 25 you have an opinion as to what you believe occurred with the
1 events?
During the event?
MR.
BERTSCH:
Just from doing some of the testing, 3
and I'm not sure -- well, of the testing we'e done so far 4
we'e not totally finished.
I'm not. sure if we'e got 5
you know, there's no real cause yet, but it looks like part 6
of the problem is the units being -- getting their logic AC 7
voltage -- or the AC voltage for the power supply is coming 8
from maintenance power instead of what we believed 9
originally was UPS power.
And so when maintenance went away 10 we lost logic power to maintain the units and they tripped 11 off.
12 And then also during the same occurrence of B-13 phase transformer going -- output going low, it wound up 14 giving the units a signal or a low voltage saying not to 15 transfer over to maintenance and with that being watched or 16 present at the time the unit will not transfer to 17 maintenance so you wind up with a loss of all output power.
18 MR.
ASHE:
Okay.
Do you have an opinion as ot why 19 the class 1-E units were not lost' 20 MR.
BERTSCH:
Class 1-E's are a different design 21 and the fact that they maintain their logic voltage from the 22 DC off a DC to DC converter.
23 MR.
ASHE:
Okay.
Could you describe current 24 changes in the -- perhaps preventative maintenance program 25 or even in the design that you'e currently aware of that or
1 that are currently being considered?
MR.
BERTSCH:
According to our vendor manual, in 3
the description section it shows the units would prefer UPS 4
output voltage over maintenance as their source for AC for 5
the logic power.
And I guess in our units it's not that way 6
and per the vendor shortly after our units they changed 7
their design where logic power comes from UPS power, output 8
instead of maintenance.
10 MR.
ASHE:
Okay.
So shortly after--
MR.
BERTSCH:
Some timeframe after according to 11 Exide, the next generation or something -- after our units 12 they changed the wiring over to the UPS preferred instead of 13 maintenance preferred which are ours.
14 MR.
ASHE:
Okay.
Is there a reason why you, 15
- perhaps, would not have been aware of that information, a
16 design change on the unit that apparently was made -- in 17 other words, would you have information that would provide 18 that information to you?
19 MR.
BERTSCH:
Not that I'm aware of, because we 20 don't get -- you know, after a unit is sent to us, we don' 21
- get, you know, the information on designs that were after 22 that.
It's like just about anything else in the plant, the 23 wordage in the instruction booklet showed that it was UPS 24 preferred instead of maintenance preferred and we didn' 25 realize it was maintenance preferred until we had the vendor
7 1
in with us doing trouble shooting and then we realized the 2
UPS is maintenance preferred.
MR.
ASHE:
To your knowledge, has any 4
modifications been made to the units prior to this event and 5
perhaps subsequent to the units arriving on site?
MR.
BERTSCH:
There has been a mod done to them 7
since they have been on site.
And that was just for ground 8
detection on the 813-A-1 board.
MR.
ASHE:
Could you explain or describe that 10 modification?
MR.
BERTSCH:
The modification was done in the 12 fact that the units are designed to come off a dedicated 13 battery and the units themselves do ground detection and 14 give you an alarm if there's a ground on the batteries.
15
- However, since we come off stations batteries 16 which supply numerous
- devices, operators perform ground 17 detection up in the control room.
And with having two 18 ground detection
- systems, is when they did a ground 19 detection test up in the control room and actually feed a
20 ground into the unit, the unit would pick up.
21 So, therefore, they decided instead of getting an 22 annunciator every time they did ground detection or a 23 certain percentage of time thereof, that was disabled in the 24
- unit, so it will not give you an alarm.
25 MR. ASHE:
In your opinion, could this have
1 contributed or was it relatable to the MR.
BERTSCH:
No, it was totally MR.
ASHE:
-- performance MR.
BERTSCH:
-- unrelatable.
MR.
ASHE:
During your servicing of the units, 6
have you observed any units having special anomalies or 7
characteristics that might be worth mentioning?
10 I'Pause.]
MR.
BERTSCH:
Let's see -- the only difference MR.
ASHE:
Are there any anomalies that you'e 11 aware of with a particular unit?
12 MR.
BERTSCH:
Unit one at UPS-1A is slightly 13 different in the fact that it's got a new generation 813-A-1 14 card in there.
So when that unit is started up, you get an 15 alarm indicating that circuit breaker 2, the DC input 16 breaker is still opened until that's closed.
And that' 17 just the fact that we'e got -- they don't make our 18 certain of our cards anymore and there's a new generation 19 card in there.
That's the only difference between UPS-1A 20 and versus 1B, 1C, 1D and 1G.
21 MR.
ASHE:
Are there any special characteristics 22 of a particular unit that you would consider undesirable 23 prior to this event occurring?
24 MR.
BERTSCH:
Not really.
The only thing we seem 25 to have problems with -- we'e had problems, you know on
9 1
occasions with CB-3 and CB-4 switching, you know, maybe the 2
design of that, but they'e not designed to be cycled as 3
often as we do -- being in a station and going through 4
startup.
But other than that, there's nothing that I MR.
ASHE:
-- can think of.
So, prior to the 6
- event, as far as your knowledge, the performance of the 7
units were satisfactory?
MR.
BERTSCH:
Pretty much.
The fact that they 9
have --
1C and 1D are running at load.
That's the only 10 problem I can see with those, but as far as the other ones, 11 there isn' 12 MR.
ASHE:
Were there any maintenance request or 13 work orders that you are aware of that suggested work to be 14 done on some units prior to the event?
15 16 replaced.
MR.
BERTSCH:
UPS-lB, to have CB-3 breaker 17 MR.
ASHE:
Why?
Do you recall why that breaker 18 was being replaced?
19 MR.
BERTSCH:
Because the motor operator wouldn' 20 have enough oomph to close the breaker -- or actually no, to 21 reset the breaker on a trip.
The unit on a transfer to 22 bypass sends a trip signal to the motor operator to open the 23 breaker and also a shunt trip signal to CB-3 and CB-3 would 24 trip, but the motor operator didn't have enough force to be 25 'ble to reset the breaker.
The motor operator was replace
10 1
previously and it had no effect.
So we suspect there's a
2 problem with the circuit breaker itself, requiring too much 3
force to reset.
MR.
ASHE:
Is there anything else, Perry, that you 5
would like to share with us that I haven't asked you?
That 6
perhaps I should have.
[Pause.)
MR.
BERTSCH:
I'm not sure what else there would 9
be.
10 MR.
ASHE:
Okay.
- Jim, do you have any additional 11 questions?
12 13 14 15 interview was concluded.]
16 MR.
STONER:
No.
MR.
ASHE:
This completes this interview.
[Whereupon, at 2:22 p.m., the taking of the 18 19 20 21 22 23 25
REPORTER'S CERTIFICATE This is to certify that the attached proceedings before the United States Nuclear Regulatory Commission In the Matter of:
NAME OF PROCEEDING:
Interview of Perry Bertsch DOCKET NUMBER:
(Not applicable)
PLACE OF PROCEEDING:
- Scriba, New York were held as herein appears, and that this is the original transcript thereof for the file of the United States Nuclear Regulatory Commission taken by me and thereafter reduced to typewriting by me or under the direction of the court reporting company, and that the transcript is a true and accurate record of the foregoing proceedings.
Mark Handy Official Reporter Ann Riley 6 Associates, Ltd.
OFFICIALTIVHSCRIPT OF PROCEEDINGS Agency:
Title:
Nuclear Regulatory Commission Incident Investigation Team Nine Mile Point Nuclear Power Plant Interview of.:
PERRY BERTSCH Docket No.
- Scriba, New York
- Friday, August 23, 1991 PAGES:
1 10 AI'&RILEY8c ASSOCIATES, LTD.
1612 KSt. N.W;, Suite 300 Washington, D.C 20006 (202) 293->9SO.
ERRATA SHEET
~Pa e 3
Line
+g n OV<
ADDENDUM Correction and Reason for Correction
'A3-A Date k
~
Signature
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION INCIDENT INVESTIGATION TEAM 6
Interview of 7
PERRY BERTSCH 8
(Closed) 10 12 13 14 15 16 17 18 19 Conference Room B
Administration Building Nine Mile Point Nuclear Power Plant, Unit Two Lake Road
- Scriba, New York 13093 Friday, August 23, 1991 The interview commenced, pursuant to notice, 20 at 1:10 p.m.
21 22 23 24 25 PRESENT FOR THE IIT Frank Ashe, NRC Jim Stoner,
- Duke, NRC
P R 0 C
E E
D I N G
S
[2:08 p.m.]
MR.
ASHE:
My name is Frank Ashe and I'm a member 4
of the Incident Investigation Team being -- as a
5 participant.
I have today, Mr. Perry Bertsch who is in the 6
instrumentation and control department and we would like to 7
record some information from him.
- Perry, could you go over and give us some of your 9
background and history with the station in terms of your 10 work activities and how long you'e been employed here?
MR.
BERTSCH: I'e been with Niagara Mohawk since 12 October of 1983.
And I came in as a technician in the I&C 13 department.
And I'e been here through most of the startup 14 and I'e worked on these units and various other equipment 15 in the plant during that time.
16 MR.
ASHE:
Okay.
When you say worked on this 17 equipment, could you explain--
18 MR.
BERTSCH:
Yes.
On uninterruptable power 19 supplies, all the ones we have on site, or at least the ones 20 that are in the plant and all sorts of other equipment.
21 MR.
ASHE:
Could you give us some of your work 22 activities, specifics of some of your work activities?
23 MR.
BERTSCH:
During start-up, initial testing, 24 calibration of valves and control circuits and control cards 25 and start-up and maintenance functions on the -- on the
3 1
uninterruptable power supplies, maintenance on redundant reactivity control system, trouble shooting repair, doing various surveillance tests on the various instrumentation that we have in the plant.
MR.
ASHE:
Okay.
In terms of the UPS that failed 6
during the event, had you previously worked on this equipment?
MR.
BERTSCH:
Yes.
MR.
ASHE:
What were some of your activities with 10 regard to working on these items?
MR.
BERTSCH:
Initial start of initial testing, 12 doing the acceptance tests on the units, and then various zs 15 preventive maintenance along the way, various corrective maintenance, you know, trouble shooting if something goes wrong, assisting operators and training them on how to do 16 various things on the units.
If the unit fails actually 17 going through there, you know, tuning down component level 18 replacement or fuses or whatever else.
Normally various 19 things like that with electrical maintenance.
20 MR.
ASHE:
Were you involved with the recovery of 21 the units following their failure?
22 23 MR.
BERTSCH:
Yes.
MR.
ASHE:
Could you, as best you could, recall, 24 explain your involvement and,the activities that you 25 participated in?
4 1
MR.
BERTSCH:
I was a member of damage control 2
team three and we went down there to attempt to restart the 3
five Exide units.
We went down and then -- let's see 4
reset the trips, closed the breakers in and'estarted the 5
I forgot the order in which we started them up in.
I 6
believe it was 1C -- started up the unit, transferred over
7 to UPS, found there wasn't any type of problem with the unit 8
in itself as far as startup or anything.
Started up or 9
attempted to start all five units.
10 We found when we closed in CB-1 on 1A, we found we 11 tripped the switch gear breaker twice so we didn't do 12 anything with that and 1-Bravo we couldn't restore to 13 service because CB-3 wouldn't close.
I put the other units 14
-- 1-Charlie, 1-Delta and 1-Gulf were returned to service.
15 MR. ASHE:
Do you have an opinion as to what may 16 have occurred with the units?
17 18 19 MR.
BERTSCH:
At the time of the event, no.
MR.
ASHE:
At the time of the event?
MR.
BERTSCH:
At the time of the event, no.
20 Because I had no knowledge of, you know, all what had 21 transcribed, you know, prior to that.
We heard we had 22 problems in the plant, but not as far as, you know, what 23 would have contributed to all the units going away.
24 MR.
ASHE:
Based on your knowledge today, would 0
25 you have an opinion as to what you believe occurred with the
II
~
1 events?
During the event?
MR.
BERTSCH:
Just from doing some of the testing, 3
and I'm not sure -- well, of the testing we'e done so far 4
we'e not totally finished.
I'm not sure if we'e got 5
you know, there's no real cause yet, but it looks like part 6
of the problem is the units being -- getting their logic AC 7
voltage -- or the AC voltage for the power supply is coming 8
from maintenance power instead of what we believed 9
originally was UPS power.
And so when maintenance went away 10 we lost logic power to maintain the units and they tripped 11 off.
12 And then also during the same occurrence of B-13 phase transformer going -- output going low, it wound up 14 giving the units a signal or a low voltage saying not to 15 transfer over to maintenance and with that being watched or 16 present at the time the unit will not transfer to 17 maintenance so you wind up with a loss of all output power.
18 MR.
ASHE:
Okay.
Do you have an opinion as ot why 19 the class 1-E units were not lost?
20 MR.
BERTSCH:
Class 1-E's are a different design 21 and the fact that they maintain their logic voltage from the 22 DC off a DC to DC converter.
23 MR.
ASHE:
Okay.
Could you describe current 24 changes in the -- perhaps preventative maintenance program 25 or even in the design that you'e currently aware of that or
1 that are currently being considered?
MR.
BERTSCH:
According to our vendor manual, in 3
the description section it shows the units would prefer UPS 4
output voltage over maintenance as their source for AC for 5
the logic power.
And I guess in our units it's not that way 6
and per the vendor shortly after our units they changed 7
their design where logic power comes from UPS power, output 8
instead of maintenance.
10 MR.
ASHE:
Okay.
So shortly after--
MR.
BERTSCH:
Some timeframe after according to 11 Exide, the next generation or something -- after our units 12 they changed the wiring over to the UPS preferred instead of 13 maintenance preferred which are ours.
14 MR.
ASHE:
Okay.
Is there a reason why you, 15
- perhaps, would not have been aware of that information, a
16 de'sign change on the unit that apparently was made -- in 17 other words, would you have information that, would provide 18 that information to you?
19 MR.
BERTSCH:
Not that I'm aware of, because we 20 don't get -- you know, after a unit is sent to us,,we don' 21
- get, you know, the information on designs that were after 22 that.
It's like just about anything else in the plant, the 23 wordage in the instruction booklet showed that it was UPS 24 preferred instead of maintenance preferred and we didn' 25 realize it was maintenance preferred until we had the vendor
1 in with us doing trouble shooting and then we realized the 2
UPS is maintenance preferred.
MR.
ASHE:
To your knowledge, has any 4
modifications been made to the units prior to this event and 5
perhaps subsequent to the units arriving on site?
MR.
BERTSCH:
There has been a mod done to them 7
since they have been on site.
And that was just for ground 8
detection on the 813-A-1 board.
MR. ASHE:
Could you explain or describe that 10 modification?
MR.
BERTSCH:
The modification was done in the 12 fact that the units are designed to come off a dedicated 13 battery and the units themselves do ground detection and 14 give you an alarm if there's a ground on the batteries.
15
- However, since we come off stations batteries 16 which supply numerous
- devices, operators perform ground 17 detection up in the control room.
And with having two 18 ground detection
- systems, is when they did a ground 19 detection test up in the control room and actually feed a
20 ground into the unit, the unit would pick up.
21 So, therefore, they decided instead of getting an 22 annunciator every time they did ground detection or a 23 certain percentage of time thereof, that was disabled in the 24
- unit, so it will not give you an alarm.
25 MR.
ASHE:
In your opinion, could this have
1 contributed or was it relatable to the MR.
BERTSCH:
No, it was totally--
MR.
ASHE:
-- performance MR.
BERTSCH:
-- unrelatable.
MR. ASHE:
During your servicing of the units, 6
have you observed any units having special anomalies or 7
characteristics that might be worth mentioning?
10
[Pause.]
MR.
BERTSCH:
Let's see -- the only difference MR. ASHE:
Are there any anomalies that you'e 11 aware of with a particular unit?
12 MR.
BERTSCH:
Unit one at UPS-1A is slightly 13 different in the fact that it's got a new generation 813-A-1 14 card in there.
So when that unit is started up, you get an 15 alarm indicating that circuit breaker 2, the DC input 16 breaker is still opened until that's closed.
And that' 17 just the fact that we'e got -- they don't make our--
18 certain of our cards anymore and there's a new generation 19 card in there.
That's the only difference between UPS-1A 20 and versus 1B, 1C, 1D and 1G.
21 MR.
ASHE:
Are there any special characteristics 22 of a particular unit that you would consider undesirable 23 prior to this event occurring?
24 MR.
BERTSCH:
Not really.
The only thing we seem 25 to have problems with -- we'e had problems, you know on r
9 1
occasions with CB-3 and CB-4 switching, you know, maybe the 2
design of that, but they'e not designed to be cycled as 3
often as we do -- being in a station and going through 4
startup.
But other than that, there's nothing that I MR.
ASHE:
-- can think of.
So, prior to the 6
- event, as far as your knowledge, the performance of the 7
units were satisfactory?
MR.
BERTSCH:
Pretty much.
The fact that they 9
have --
1C and 1D are running at load.
That's the only 10 problem I can see with those, but as far as the other ones, 11 there isn' 12 MR.
ASHE:
Were there any maintenance request or 13 work orders that you are aware of that suggested work to be 14 done on some units prior to the event?
15 MR.
BERTSCH:
UPS-1B, to have CB-3 breaker 16 replaced.
17 MR. ASHE:
Why?
Do you recall why that breaker 18 was being replaced?
19 MR.
BERTSCH:
Because the motor operator wouldn' 20 have enough oomph to close the breaker -- or actually no, to 21 reset the breaker on a trip.
The unit on a transfer to 22 bypass sends a trip signal to the motor operator to open the 23 breaker and also a shunt trip signal to CB-3 and CB-3 would 24 trip, but the motor operator didn't have enough force to be 25 able to reset the breaker.
The motor operator was replace
10 1
previously and it had no effect.
So we suspect there's a
2 problem with the circuit breaker itself, requiring too much 3
force to reset.
4 MR.
ASHE:
Is there anything else, Perry, that you 5
would like to share with us that I haven't asked you?
That 6
perhaps I should have.
[Pause.]
MR.
BERTSCH:
I'm not sure what else there would 9
be.
10ll questions?
MR.
ASHE:
Okay.
- Jim, do you have any additional 12 14 MR.
STONER:
No.
MR.
ASHE:
This completes this,interview.
[Whereupon, at 2:22 p.m., the taking of the 15 interview was concluded.]
16 17 18 19 20 21 22 23 24 25
A J
REPORTER'S CERTIFICATE This is to certify that the attached proceedings before the United States Nuclear Regulatory Commission In the Matter of:
NAME OF PROCEEDING:
Interview of Perry Bertsch DOCKET NUMBER:
(Not applicable)
PLACE OF PROCEEDING:
- Scriba, New York were held as herein appears, and that this is the original transcript thereof for the file of the United States Nuclear Regulatory Commission taken by me and thereafter reduced to typewriting by me or under the direction of the court reporting company, and that the transcript is a true and accurate record of the foregoing proceedings.
Mark Handy Official Reporter Ann Riley
& Associates, Ltd.
r