ML19332D398
| ML19332D398 | |
| Person / Time | |
|---|---|
| Issue date: | 11/14/1989 |
| From: | NRC |
| To: | |
| References | |
| FRN-55FR29043 AD04-1-022, AD4-1, AD4-1-22, NUDOCS 8912010139 | |
| Download: ML19332D398 (79) | |
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OFFICIALTRANSCRIPT OF PROCEEDINGS 1
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Nuclear Regulatory Commission i
Tide' Public Workrhop on Technical and t
Policy Considerations-for Nuclear Power Plant. License Renewalt l
Docket No.'
Electrical and I&C' Systems I
SESSION 7
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i LOCATION:
Reston, Virginia DATT.:
Tuesday, November 14, 1989 PAGES: 1 - 61' l
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ANN RILEY & ASSOCIATES, LTD.
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(20?) 293-3950 8912010139 091114 PDR MISC j
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1 UNITED STATES OF AMERICA v
2 NUCLEAR REGULATORY COMMISSION I
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PUBLIC WORKSHOP 6
ON 7
TECHNICAL AND POLICY CONSIDERATIONS 8
FOR f
9 NUCLEAR POWER PLANT LICENSE RENEWAL f
l 10 11 ELECTRICAL and I&C SYSTEMS I
12 q.
i 13 SESSION 7 14 15 i
16 Sheraton Resort Hotel
.5 17 Conference Rooms A, B and C 18 11810 Sunrise Valley Drive 19 Reston, Virginia 1
20 21 22 Tuesday, November 14, 1989 i
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23 8:30 a.m.
24
. 25 i
I 2
r lH, 1-SESSION LEADERS:
2 Ashok C. Thadani, Director, Division of i
3 Engineering Technology j
4 Milton Vagins,. Chief, Electrical and Mechanical i
5 Engineering Branch, Division of Engineering 6
i 7
PARTICIPANTS:
8 George Sliter, EPRI 9
Robert McCoy, Yankee Nuclear Power Station 10 Bill Simmsac, Yankee Nuclear Power Station 11-Kirt Coueas, NUMARC y x)
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12 Faust Rosa, NRC 13 J.B. Gardner, Consultant 14 Peter Bloch, NRC 15 Karl Neil, NkC 16 Mannie Day, NRC
.17 Bill Hingle, Yankee Nuclear Power Station 18 Mr. Farmer, NRC 19 20 t
21 22 24 25
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.1 PROCEEDINGS 2
(3:30 a.m.)
i 3
MR. THADANI Let's begin Session No. 7 on 4
Electrical Systems.
I an Ashok Thadani, director, 5
Division of System ?.chnology, the oftice of Nuclear 6
Reactor Regulations.
Co-chairicg this session is Mr. Milt 7
Vagins.
Ha is chief, Electrical and Mechanical 8
Engineering Branch, Division of Engineering.
9 Our purpose here is to receive comments from your 10 discussions and questions.
Before we get started, Milt 11 has a short presentation to try to focus our attention on l
12 the specific issues.
Milt.
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13 MR. VAGINS:
Those of you who are in the session, i
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14 before I start, I'd like to do a little housekeeping.
Can 15 you hear in the back?
The transcripts will be available 16 ofLall the sessions of the workshop.
I would like for all L
17.
prepared speakers to give us a copy of their viewgraphs, i
18 if they have tham.
The transcripts will be available from i
19 Ann Ri y & Associates, 1612 K Street, N.W.,
suite 300, i
- 20 Washing'*on, D.C.
20006.
i 21 Again, before we begin, I want to reiterate what 22 the basic concepts of the License Renewal Rulemaking is j
![J) 23 following in the area of technical issues, and there are 24 four basic driving requirements.
The rule will define or 25 specify a proposed screening process of equipment and
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1 structures.
It will define some structures systems and 2
components for evaluution, some for exclusion.
It will 3
define a specific set of degradation mechanisms-for l
4 evaluation and also define requirements for corrective 5-action when degradation is not.being monitored.
This is 1
6 the basic overall philosophy.
We tie that together with j
7 the understanding, the basic logic of licenso renewel, and i
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that can be expressed ic four simple words, " assurance of 9
continued safe operation."
No enhancement, but assurance 10 of continued safe operation.
Tnat is the key, and that is l
t 11 what we'll be driving to.
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12 The questionJ that were sent out to you on the i
13 original set of questions were six.
Question threo, which i
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l 14 dealt with industry experience with electrical equipment
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15 which exhibit high failure rates during their design life 16 was inadvertently built in.
It was decided by the staff l
l 17 that that is really a today issue.
If we are 18 experiencing -- and I say if we are experiencing a high
- 10 failure rate of equipmeat today, then we must solve that 20 prob?.em.
It is to not a license renewal issue.
So that l
21 kind of question will not be addressed unless somebody 22 really wants to address it.
But again, understanding jf 23 we have a problem today is u.cumbent upon both the 24 industry and the NRL
- a solve that problem.
25 VOICE:
"nu would expect on the wr?tten responses
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1 that would not be addressed?
2 MR. VAGIN8:
Again, I think the written responses L
3 would be irrelevant because it's not a license renewal 4
issue.
I regret and I apologize that that did creep in.
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It is contra to everything else we've done.
The key word, 6
again, is today issues to be solved today.
License 7
renewal will address those issues which are not defined or i
8-resolved and by the degradation of something beyond the 9
scope of the present license.
10 In that case, let's look at the five remaining l
11 questions, and I'll paraphrase them.
The first one is
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12 what additional criteria for electrical equipment included 13 in the EQ program, but not periodically replaced, is 14 required.
The big question here, of course, is cable, 15 cables within containment.
How do you propose, or how do 16 you auggout that we deal with equipment that is EQ to end t
17 of life. no further, and is going to be very, very 18 difficult to replace.
19 The second question dealt with additional 20 programs to address aging degradation of electrical 21 equipment located in mild environments.
Again, not 22 subject to EQ as is the case with equipment subject to L
23 harsh environments.
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24 Third is: programs to establish the in situ A5 condition of cable and components and the potential for
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1 future degradation.
Again, to a great deal this goen back 2
to cable.
But it also deals with electrical equipment
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3 that is not normally followed too closely.
Some of that 4
will be' relays, for instance, for requirements for 5
electrical equipnent important to safety.
That is an 6
electrical question.
How do we deal specifically with 7
electrical equipment?
Again, the importance is not j
8 necessarily safety related.
9
-Fifth was functional testing of electrical 10 equipment as a prerequisite for license renewal.
Is 11 functional testing or r.ew baseline testing of value o.-
/D 12 importance or need?
We would like your inout on that.
-%_f 13 Let's talk a little bit about the electrical 14 systems themselves.
Just an e : ample, so we're all talking 15 about the same thing, we have those electrical systems l
- 16. relied upon for the integrity of pressure boundary and to 17 effect safe shutdowns and accident prevention and 18 mitigation.
I've listed some of the equipment.
We ali 19 know reactor protection systen and engineered safety 20 features, are Class 1.
But then there are other systems, i
21 electrical systems, whose failure can cause or adversely 22 affect a transient er accident, significantly challenge 23 structures, systems and camponents relied upon for the 24 integrity of the reactor coolant pressure boundary, safe 2t shutdowns, or mitigation and, of course, mein generator 1
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1 and reactor control system and switchyard.
Failure of 2
these components challenge the system.
In some cases the t
3 switch-of f f ailure leading to station blac.kout seriously 4
_chillenges our safety systems.
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This is just a short, very short, and h;rdly, by 6
no means, comprehensive list, but just to give you-an idea 7
of breakdowns to various areac of equipment we're looking P
R at.
We're certainly looking at the importance of balance 9
of plant in license renewal.
10 With that brief summary, I'll open the floor to 2
l 11 questions.
Then we will move into the prepared
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12 ' statements.
Are there any question or comments about what l
13 I just said?
Please stand up and identify yourself and l
14 talk into the microphone.
15 MR. COZENS:
I'm Kirt Cozens. NUMARC, and I just l
l 16 wanted to verify your use of the term " challenge to l
17 safety" in connection to important to safety systens.
18 Does this go beyond the definition of important to safety 19 that has been written in the NRC rule and also beyond what 20 the industry has proposed for screening structures, 21 systems and components for degra'ation.
22 MR. VAGINS:
It depends on what the industry
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When we say l
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24 challenge to safety -- importance to safoty, if a system L
25 fails which prevents a safety system from working, then,
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1 yes, that is in the rule, the proposed rule.
The question s,
2 is how far beyond.
For instance, if a switch yard, if I
3 that fails, we face severe problems, and yet that is not 4
really defined as safety related or -- obviously it's f
5 important to safety.
So should we deal with it?
It's 6
also a system in which we have determined that i
7 transformers age.
Thuse are part of the aging programs, 8
so the question becomes:
we'd like to know your views of j
9 how we treat these other systems.
We want your input.
10 MR. THADANI As you know, there was a session 11 yesterday, there was considerrable discussion on this l) 12 specific issue in the screening techniques session.- The t
13 question was raised on the initiator important to safety.
l 14 There is no question about what the answer is; they are in 15 fact very important.
They impact safety.
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17 equipment important to safety and does that include any
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The language, if I were to take a look at the 19 language, one could interpret it any way one wants.
The 20 response from certainly one industry member was that you l
21 pick up some of those systems simply because you're 22 looking at mitigating systems.
If you are looking at the 23 definition of important to safety, I think the words are 24 something like " systems are required to prevent or 25 mitigate accidents"; and so you would pick up feedwater 1
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1 systems, and one could also interpret that to mean that 2
you could also pick up power supplies, because you need h
3 them to be able to mitigate certain types of events.
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We have received a number of comments on that, l
5 and I think de do need to deliberate on the significance 6
of those comments.
We will probably uummarize those 7
comments this aftsrnoon.
But to reiterate, the focus 8
really should be the concern of significant aging 9
degradation with equipment important to safety.
i 10 MR. VAGINS:
Again, I wante to reiterate, the 11 key is, as Mr. Thadani has pointed out, what is changing
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12 within the new license period.
And here we're dealing 13 with aging degradation which, of course, as you know, has 34 a continuing function, and doesn't start at year 41.
It 15 starts now-and goes on continually.
16 With that comment, I would like to ask the i
17 speakers who have submitted or have requested time to i
18 speak.
First of all the representative for from NUMARC.
19 Do we have a representative from EPRI?
Yes.
20 MR. SLITER:
Good morning.
I'm George Sliter.
21 from EPRI.
I'm the manager of EPRI.
I'm here to comment 22 on the aging and qualification prooram.
I'm also a 23 technical advisor to the NUMARC/NUPLEX Task Group for the
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24 cable industry report for life extension of cable.
I'll 25 be talking tnis morning about life extention of electrical
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1 systems and components.
It's important to point out in 2
starting, because yesterday we heard about mechanical 3
systems and reactor pressure vessels.
For electrical 4
systems and components, we have a unique situation, as f
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5 compared with mechanical systems, for two reasons, 6
One, aging of electrical components is addressed i
7 explicitly in existing regulations and standards.
It's
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8 addrassed explicitly in the equipment qualification rule f
9 10 CFR 50.49.
That is the first reason.
So age is 10 certainly not a new thing.
It's not a new thing in i
11 general, but specifically for electrical equipment.
12 Secondly, the scope of the NRC conceptual rule f
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13 that you have before you says that it probably will follow 14 the scope of the equipment qualification rule and that is 15 components and equipment important to safety.
I think 16 it's very appropriate for the conceptual rule to follow 17 the definition of important to safety that Milt Vagins 18 went over this morning, 4xcept that it is my understanding 19 that something like the switch yard outside the bounds of 20 equipment important to safety called out in the rule.
The 21 reason is we know that the plant is designed for loss of 22 off-site power, and any failure in the switchyard would be
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23 no more challenging to the safety system of a plant 24 anymore then loss of off-site power.
So the rule itself 25 would not include, for example, a switchyard in its t
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1 important to safety definition.
2 May I have the the tirot graph, please?
So to 3
continue on this morning's note, we have an EQ rule.
It's 4
It addresses aging degradation of all 5
significant safety components.
Typically when people talk 6
about the rule in equipment qualification, they say it 7
applies only to harsh environment equipment.
Indeed, it 8
says that that is the main focus of the 50.49 rule, and 9
that it does not cover mild environment equipment.
10 I want to make two points there.
First of all, 11 regulations, peripheral regulations do address the D( )
12 qualification of mild environment equipment.
For example, 13 one place it shows up is in the stitements of 14 consideration supporting 10 CFR 50.49, and I quote from 15 those statements of consideration.
The commission has 16 concluded that, "The general quality and surveillance i
17 requirements applicable to electrical equipment as a 18 result of other Commissior regulations, including 10 CFR 19 Part 50, Appendix B,
-- see, for example, Regulatory Guide 20 1.43, Quality Assurance Program Requirements, Revision 3, 21 ace sufficient to insure adequate performance of 22 electrical equipment important to safety located in mild
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23 environmentc."
24 Secondly, of importance to that for mild L
25 environments, is the fact that the screening criteria will A
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definitely be applied to mild environment equipment,
~2 looking (or significant aging degradation that may impact j
3 the long term operation of a plant.
4 Secondly, the EQ rule covers both old and new 5
plants.
Typically we think sometimes that the rule covers i
6 only the new planto because the rule does endorse 7
IEEE-323, which does apply and is committed to only by tho l
8 newer plants, but the rule endorses, as well as the DOR 9
guidelines, and it is important to know that thoce older 10 plant regulations for the older plants do address aging i
11' explicitly.
A quote from the DOR guidelines.
" Equipment 1
l) 12 using materials that have been identified as being 13 susceptible to significant degradation due to thermal and L
14 radiation aging are included.
Component maintenance or 15 replacement schedules should include consideration of the 16 specific aging characteristics of the component 17 materials."
4 18 Next, it's important to note that the equipment 1
19 qualification rule does not limit the component life to 40 20 years, and it allows the re-evaluation of the qualified L
21-life, i.e.,
if you initially qualified to 20 years, the 1
22 rule says you can re-evaluate it and maybe qualify it on 23' the basis of operating data or new data for five years.
24 On the other hand, if qualified for 40 years, you 25 look at the data, the operating environment, and you
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1 qualify it for, let's say, 60 years.
So the EQ rule j
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exists and it will be continued for the extended term.
3 There are generally two types of equipment, short 4
lived components that are replaced periodically on an 5
interval less than 40 years, and for these components, no u
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additional license renewal is required.
7 Another is long lived componenta.
They will i
8 generally require extension of their qualified life or j
9 alternatively, be replaced.
Of the several equipment t
10' types that have a qualified life of 40 years, cable is l
11 especially important.
It has inherently great
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12 significance because it's the lifeline of the plant power
.13 control and safety systems in plants, and it is also very i
14 expensive and difficult to replace.
Therefore, the i
15 industry report-right now is being prepared for cable in 16 containment.
i 17 The remainder of my remarks will mainly give you 18 examples of how long-lived components are being addressed.
19 I'm now turning my attention to ongoing work for the 20 industry report for cable.
First, let me go over 21 something that has been talked about at other sessions, 22 but in case someone has come only to this session, let's 23 talk about a general outline of industry reports that are 24 being prepared.
This gives you the steps and process to 25 first determine the component systems and structures that
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1 are safety significant.
For cables, this would mean that l
2 the cable circuits and systems are those that are called 3
out as important to safety in the equipment qualification
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4 rule, and you would determine that when you go through 5
your screening process.
Next the IR would describe all 6
plausible aging d9 gradation mechanisms, anything that can 7
realistically be thought of as degrading a cable.
8 Third, you would determine which age related 9
degradations are potentia?ly significant.
And by i
10 potentially significant we mean degradation that could 11 reasonably be expected to cause common mode failure.
It's
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12 important in all of this equipment life extension work to 13 recognize that it's not a single failure that we're t
14 looking for.
Random failures can be demonstrated due to 15 built in redundancy of safety systems.
Is it reasonable 16 to expect that they could cause a common mode failure not 17 only during operation of a plant, but also under any harsh 18 environment that it might see in an accident?
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19 Next for those potentially significant age 20 related degradation mechanisms, we need to determine if 21 established inspection, testing or analysis procedures, as 22 currently implemented, bound age related degradation
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These acceptable V
24 limits for cable are called out by the rule and by 25 associated regulations and standards.
In particular for
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1 cable, the acceptable limits are called out in IEEE 2
Standard 383.
Lastly, for the significant age related 3
degradation mechanisms that could be beyond the 4
established limits or cannot be shown to be within 5
established limits, utilities would establish degradation 6
management activity for the cable.
In my remaining 7
slides, I'll show you some of the options that are under 8
consideration for cable in this area.
9 Now I'll go through some of the highlights of the 10 emerging industry report on cable in containment.
The 11 work is being prepared DOE, and it is being reviewed by D
12 the NUMARC/NUPLEX Utilities Task Group for Cable.
It's in a'V 13 progress and the target date is June of 1990 for the 14 completion of the IP..
The main scope of that IR is cables 15 in containment that are significant to safety.
Any mild 16 environment or even harsh environment cables outside 17 containment would be outside the industry report.
- Again, l
L 18 we can tell which cables are in the scope by using the 19 screening criteria and that is applied in the industry 20 report.
21 Next, going down the IR process we identify in 23 the report the evaluation basis, the standards of 23 regulation that applied to cables.
Those are, again, the 24 qualification requirements of 10 CFR 50.49 and in all 25 qualification documents that call out the maintenance that k
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1 one needs to do to maintain a qualified life of equipment, s-2 whether it be replacement, refurbishment, inspection, or 3
whatever.
4 secondly, it's important to note that the way 5
equipment was qualified was by using a conservative design-6 to estimate temperature and radiation.
So there is 7
built-in conservatism that for many long-lived component 8
can be taken advantage of when you go for life extension.
9 Next, operating experience for cables has been 10 very positive.
It turns out that actual environments in 11 the plants are generally substantially milder than those 12 used in the-design of the cables.
This has come out, for 13 example, in EPRI in a plant aging program which has 14 electrical components including extensive cabling in eight 15 operating plants in the United States, and measurements 16 from that program are showing annually that the 17 environments are significantly milder than those designed 18 for it.
19 Secondly, cables have shown an extraordinarily l
20 high reliability in normal operation, which is no L
21 surprise.
They're passive, they're designed for really 22 harsh environments, and here they are sitting in a normal
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23 operating environment, and it turns out in the Sandia 24 program looking at cables they have looked at the 25 experience record and shown there has been less than one
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17 73 i
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1 half age-related cable failures per plant here in i
2 operation for the past 20 years of U.S.
nuclear plant l
3 operation.
4 When we say failure, and it's something that 5
should be brought out in a number of these sections but 6
really isn't, a lot of people talk about failure rate 7
curves.
In many cases, they are nothing more than a thing 8
not meeting some surveillance requirement, it's outside 9
its normal acceptable limits so it's more of a -- it could 10 be as little as slightly out of calibration or not meeting L
11 some limit, and it's called a failure and it's plotted.
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12 Those are simply the new failures that are of importance 1
l 13 when one is trying to protect how reliable and safe a l
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14 plant is.
So let's turn now, going on to the IR for 15 cables.
16 My next bullet in the next viewgraph lists all of t
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17 the plausible age related testers that could produce aging 18 in cables.
They include temperature and self heaters, l
19 1.e.,
heating in cable radiation, moisture, chemical 20 effects, mechanical effects, stress and strains, 21 abrasions, and electrical degradation.
The IR will go 22 through and analyze all of the plausible age related l.
23 mechanisms, and that work is now ur.derway.
The list could 24 be quite long.
It includes mechanisms that act on 25 conductore cr that act on insulation itself and that act
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1 on the jacket, the entire system, and cable system, and 2
installation system.
However, wnen it comes down to which 3
ones are the plausible or perhaps safety or significant 4
degradation mechanism, the three general ones I have here 5
really cover all of the grounds.
The first is thermal and 6
radiation embrittlement of insulation, and by that I mean i-7 ihe insulation system which could cause cracking and loss j
8 of its function, especially during an accident.
9 secondly, and especially for instrumentation 10 cable, a loss of installation resistance of the cable.
11 And third, general categories, mechanical wear that
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12 includes things like vibration creep over the hard points 13 when it's hanging over a hard point along its cable tray j
14 and mechanica1 wear due to handling during maintenance as j
15 the plant operates.
What will happen now is the IR will 16 look at the plausible ones and identify which of those are 17 potentially significant with respect to common mode 18 failure.
That has not been determined yet.
So note that 19 there are other plausible, conceivable degradation 20 mechanisms that are listed in the PLEX rule.
I think 21 right now the conceptual PLEX rule puts down all the 22 conceivable ones, but we'd like to point out that some of 23 those are simply not plausible for cable in relation to 24 corrosion of the polymeric insulation and chemical effects 25 just are not plausible for cable.
So for the component
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19 9
1 life evaluation, to establish the bounds, what will be 2
done is a re-analysis of qualified life according to the 3
EQ rule using the original data for the cable, but taking 4
advantage of the conservatisms -- mainly the conservatism d
5 in the design of the cable to accommodate environmental 6
conditions.
7 While you're at it, you also need to add ass any 8
issues that have been brought up over the years by 9
research.
For example, the effects of combined 10 environments acting simultaneous and the cable dose rate 11 and the effects, if any, of those that have shown to be h
12 significant, they will be taken into account in this 13 re-analysis.
14 Secondly, the evuluation and bounds also relate 15 to maintenance that is based on current regulations and 16 standards.
17 Now we're into the screening proceso here.
We've 18 listed a plausible mechanism and those that are bound to 19 it.
It may turn out that some cannot be shown to be 20 within the acceptable bounds for say, a 60-year life and 21 for those managing methods for aging degradation, they 22 will and are being developed for the industry report.
'23 Those management options could include such things as
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24 environment monitoring, condition iaoni toring, and 25 inusection reconfiguration, operat:- r.1 changes, and g.
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1 requalification based on n'w test data not commissioning 2
test data and replacement.
3 Environment monitoring is very important 4.especially if you'want to take advantage of conservatism 5
for. life extension.
I'd like to announce that there will d
6-be an EPRI workshop on environmental monitoring of 5
7 equipment this coming year, April 10, 1990, to exchange 8 -information on the topic of monitoring environments.
In Condition monitoring there is lot of work 9;
10 going on developing improved methods and if those are 11 useful for life ey. tension, and if they turn out to be 12 practical, they could be used.
Inspection would look at 13 such things as located hot spots in the plant and also 14 looking near the ends of cables near a termination because 15 these are areas that are subject to degradation for 16 maintenance handling.
So either in your maintenance
_h 17 program itself or additionally as a separate walk-down, U
1R you'd want to look at those areas.
19 Reconfiguration means rerouting cables.
If it's 20 in.a hot spot, you might want to reroute it.
Operational 21 change _ight be reducing a current in a cable to reduce gg 1
22 self-heating-i 1
23 In conclusiva, then, I'd like to state the 24 NUf! ARC /NUELEX working group conclusions with regard to
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25 electrical systems.
It appears that there is no need for
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a regulatory guide in liou of the existing rigorous s-2 -equipment qualification regulation 10 CFR 50.49, and the 3
guidance that contained in Regulatory Guide 1.8.
'The 4
outlined conceptual rule seems to be month to month wit'h~
5 regard to the use of existing EQ rules.
But it needs to 6
reflect more the NRC philosophical positions regarding the=
7-credit'for ongoing programs, which here are clearly 8
equipment qualification programs, and also the need to 9
address only significant age related degradation, and the 10 screening process developed by the industry will identify 11 those significant age related degradation areas.
Thank (D
V 12 you.
13 MR. VAGINS:
Are there any questions or 14 discussions on what George has presented?
The only 15 comment that I havn, of course, is-that mice and rats have 16 been known to change the configuration of electrical 17 systems and they're not included in either your studies or' 18 mine.
Mice are a plausible possibility.
Are there any
'19 questians?
20 I think George made a very fine presentation and 21 I think this is one area in the electrical area where we 22 have got to try and the NRC bas spent a great deal of h
23 effort in the aging programs long before it became 24 fashionable; it is not the only crea.
I think pressure
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i 25 vessels for the last 25 years have spent time on aging
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1 there, too.
2 Question?
3 MR. ROSA:-
Faust Rosa, NRC.
George,.at the i
4 meeting I attended a couple of years ago in San Francisco, 5
ths question of detecting mechanical damage to cables in
~6-condos was a pretty heavy copic of discussion.
What are 7
the developments in that area, because I think the L
8 possibility of widespread mechanical damage may pose.~uite-l 9
a problem?
10 MR. VAGINS:- I think that issue was raised in one 11' of the-questions.
So let's bring up that question.
(_)
12 MR. SLITER:
I was going-to raise my hand _and ask L
- 13. the questi"J., ao I'll ask my questions first because it L
14 has to do with_yours, I think.
Then I'll answer question 15L number four.-
It says most cable has been qualified for 40 16 years, 100 year life as demonstrated in certain installed s
17 applications and conditions, including environment, 18 pressures, cable, electrical loading and cable mechanical 19 loading for which a cable was designed.
20 Here is my question.
Given that manufacturers 21 have provided certain important initial parameters for new L
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22 cable, what kind of programs should be proposed that could
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23 be instituted to establish the in situ condition of a p
.s 24 cable and the potential degradation that would take place l.j 25 beyond the current design life?
What is the meaning of
23.
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1 importanance of initial parameters?
2 MR. ROSA:
I would attempt to address things like 3
mechenical strengths of the insulation, the jacket, the 4
ir.aulation resistance of new' cable, for instance, things 5
of that nature.
6 MR.-SLITER:
The answer to your question, Faust, 7-is'first and'aost importantly, that the issue you raised 8
is'a new issue.
The plants need to have installed-their
-9 cables according to good practice, and if they are not, it
' s a new issue.
Given faulty installation, it is not i
10 11 plausible or significant that aging-would worsen things.
l i
U 12 If you damage the cable on the way in, that is your main.
J 13 Edamage.
The aging is not going to increase too much over 14 years.
l L
15 So the important thing to realize is that cables
{
16 need to be installed properly, and if indeed there is some L
[
17' kind of a problem somewhere in the installation, it more 18 than likely would be taken care of by the. single failure-19-thing.
It would have to be widespread and rampant abuse 20 of installation practice before you could ever get into a 21 mode in which you're likely to have a failure mode.
So, 22 first, it's a new issue.
Second, it's covered by 7'N 23-redundancy of safety related systems.
But let's just tack O
24 on here now, outside the scope of life extension that it 25 is indeed an issue for at least one particular plant.
24 A
1 We all know that TVA had that particular problem, s
2 arul indeed if any. plant is having problems in their cable.
J 3
systems, it would be good if we had a condition to monitor 4
or an in situ test technician that could go in and test 5
the cable'and tell whether it was okay or not.
EPRI is-6
'trying to develop some methods.
7-MR. VAGIN8: I do want to make reference to what 8
was said about cable.
Today there is a problem that will-9 extendTinto life extension.
I think monitoring programs t
10 are significant.
NRC has cable monitoring programs that 11 NIST -- I'll never leatn tc say that correctly -- it was A(,)
12 'the NBS, and of course George has his programs and we will 13 hopefully come up with some good cable monitoring methods, 14 and they, of course, will then be available to be applied
-15 to now, to tomorrow, and-the day after.
16 Are thare any more questions or discussions for 17 George's presentation, which I think is a good one?
The 18 next speaker scheduled is someone from Northern States 19 Power, Monticello.
Anybody here?
How about Yarikee?
20 Yankee will speak.
21 MR. MCCOY:
Good morning.
My name is Bob McCoy.
22 I'm here representing Yankee.
I'm a senior electrical
[O^I 23 engineer there for over five yeare.
The last few of those 24 years I've been on the licensing renewal project.
I'm 25 also vice chairman of IEEE Working Group 4, which is
e 25-l
?-%
(_/-
1 presently writing a guide on the aging assessments of 2.
Class 1 equipment, and I'm also helping George with the 3-cable' industry record.-
(
4 The primary function of electrical and I&C i
5 systems is to provide power, control, instrumentation to 6
fluid and mechanical systems.
The I&c systems are 7
generally composed of similar Tdl.
'aceable i
8 components.
9 Section XX.9-I r=
at as Section 9 as s'sig, j
10 -we go through, requ iden.
T v v
11 requirements, functi and eav :,-Sme'i te
.ondit ions,
.O 12 degradation of mechanisms, and also rer 2res programs to (j
13 identify, evaluate, and trend effects of relevant 14 degradation for all equipment important to safety.
15 I stress that it requires it for all equipment.
16 It's our contention that Section 9's-scope is-17 unnecessary.
It's recognized that degradation concerns do 18 not exist for many components.
This is because of design 19 considerations, benign ent :onmental conditions, 20 inspection, and maintenance programs, refurbishment or 21 replacement programs.
Tha rule needs-to consider these 22 factors so that re
- :n c ec t.a focused on the areas 23 warranting attenti m
~24 Se< tion 9 differs in this regard from the NRC's 25. expressed philosophy on page 10 of the proposed rule which x
Ji:
y 26 d
1 states, "Those structures, systema, and components that 4
2
'are effectively covered by existing ongoing NRC i
a subject 3
requirements and/or licensee programs, or are not 4
to aging mechanisms, need not be addressed in the 5
application."
6 Now coming back to electrical and I&C components, 7.
what causes degradation for electrical and I&C components t
8 is temperature and radiation, with also some effect'from l
9 the operation of the equipment.
Many of tr.ese components In are located in areas with controlled temperature'and 11 ' radiation, and they're in the mild environment.
Many of J.
12 those components are also covered by existing programs 13 which maintain, refurbish, and replace its coIaponents.
14 It's these programs that have been proven effective over 15 years of operation, and they are continued-to be updated 16 as we learn more.
17 Some. examples are I&C setpoints.
We look at 18 instruments and see its setpoints starting to drift.
If 19 it drifts too far or too often, we'll refurbish the 20 instrument.
Another is battery testing.
Periodically we 21 do a performance discharge test or a capacity test.
We 22-replace the battery when it reaches 80 percent of its.
('s 23 capacity.
This is in accordance with the IEEE standards.
.v]
24 Class 1E equipment must meet their safety 25 functions over the installed life of the equipment.
This
)
j 27 zs 1
S-l' is accomplished through a program of quality assurance,
-2 design', qualification, production, transition, storage, 3
installation, maintenance, surveillance, and periodic O
4 testing.
Thus the class lE equipment is continuaAly 3
5 maintained, refurbished and replaced.
They must meet 6
their safety functions throughout the initial licensing 7
period.
With the continuation of these programs, Class 1E y
b 8
equipment.can safely be licensed for a licensing term.
l 9
Some programs are periodically being replaced.
10 Functional testing, calibration, monitoring the cause of 11 degradation -- and what I mean by that is what Georgo
' O(,j 12 Slitet. talked-about earlier.
Maybe we can monitor the 13 onvironment if that is the cause of degradation.
These 14 programs-are continually updated and they improve with.
15.
time and knowledge.
We're learning all the time.
16-Another example is environmental qualification in 17 accordance with 50.49.
This requires that an aging 18 analysis be included to demonstrate the equipment's 19-operability.
50.49 will be applicable during the license 20 extension as well.
So this should not be required to be-21 addressed on the application.
22 In conclusion on these existing programs, I'd 23 like to make it so that the rule should allow flexibility 24 to credit existing programs where they're found to be 25. effective.
What we're looking for are those components 1
.,..,s
.(i 28 w-I f.
k,_
'l
_that are_not.uneffective programs.
Degradation mechanisms-2 are understood based on years of experience, but the 3.
understanding is continuing, especially in environmental 4
and material interactions.
5 Some-examples _of the degradation mechanisms we've 6
come to find, are thermal and radiation embrittlement,
[
7-loss of. dieluctric' strength, and loss to dielectric 8
strengths also-means loss of installation resistance.
9 They have different connotations.
For most components, 10
-analyzation and insnection of sctual conditions will help 11 to define the degradation mechanisms.
Some will be l^
f"N
.,12 defined by turther evaluations.
For example, the cable
()
13 ;- industry. as George discussed earlier, is under an 14 'in'dustry investigation to determine if conservatism in the L
15 design and application is adequate to allow continued l
1 L
16 operation through an extension period or should we apply s
17 'some additional inspection prograns.
18 Managing degradation mechanisms.
Additional 19 programs should only be a requirement for equipment l
20 important to safety.
No additional programs should be 21 required - f or those covered under exi s tir,9 programs --
1 22 existing and effective programs.
For example, the EQ rule l
23 should allow flexibility to credit these programs.
q 24 Several methods that can be viewed for managing 25 degradation.
One is further analysis which can show that l
[
29 9
.1 ls.)[--
l~8 1
the degradation is acceptable.
Another-is a current l
.2 program that can assure that'the degradation results in-no t
3-safety impact.
"Jo urge that procedures may heve to be 4
enhanced-in some cases and that is another method of
.5--managing degradation.
For example, we can use some -
.t 6
trending.
Wo.can change operating practices if the
.i 7
degradation-is based on the operation of the equipment, or 8
we can replace and refurbish it even periodically or based 9
on some indication.
10 I~ touched on trending on the last slide.
But L
11 -trending should not be applied unilaterally to all 1
12 equipment.. Some examples where existing programs j
j 13. suffice --
if we replace the equipment before it 1
14 degrades, for example, setpoint drift; or if'there is 1b existing-programs that periodically refurbishes the 1
,16 components we need not trend; or third, by operating so
(
17 that-degradation is not a concern.
For example, the 18 number.of systems for the environmental conditions.
19 The point I'm trying to make is we should 20 efficiently apply trending only where meaningful and 21 justified.
-Administrative controls should be implemented 22 to those specifications that are required to manage
()
23 degradation.
These can be maintained as licensed V-24 components.
25 I'd like to bring us back to Section 9 of the
c i
30 o
s p
,q.
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' proposed rule.
Section 9 should be a screening process.
L 2
The screening process should be based upon important to p-
[
3
~ safety not covered under existing programs and subject to l-4' significant degradation.
Thank you.
5 MR. VAGINS:
I think Mr. McCoy's presentation, L
6 again, reflects Yankee's continuing and ongoing valued efforts which, along with Monticello and Northern States 8
Powpr, represent real efforts.
Are there any questions or 9
any statements concerning Mr. McCoy's presentation, which 10 I thought was very thorough?
u 11 MR. ROSA:
Faust Rosa.
I have sort of a hang up
'n l
)=
12 ith cables in containment.
I don't understand how an 13 ongoing equipment qualification program on cables in 14 containment can be used to the extent of the qualificatior.
15 of those cables?
16 MR. SLITER:
I think, Faust, the problem y)u may 17 have is not understanding the total concept and approach 18-that the industry has-used to qualify cable.
I suggest.
19 you look in IEEE-323, not that it applies to all" plants, 30 but the concepts do.
Qualification is not only a test in 21 the local chamber.
It goes way beyond that.
In the 1
q 22 introduction to 323 it saye, " Qualification is based not i
(~'l 23-only on testing, but on a good design installation, q;
24 maintenance, QA, the whole smear that is qualified cable.
f 25 And.there is no question in anyone's mind that if someone 2
+
a f
31 n
oJ%
1: does a poor job in any one of those areas, they may 2
violate the qualified status of cable.
EIt's advisable not 1
3 to violate any one of those.' What is it you don't 4-und6rstand?
r.
5 MR. ROSA:
I guess it's the fact that the procing.
6 element.in the qualification' programs for cable or any 7
other equipment is a test.
And we have performed ter.ta on-8 these cables in the local environment, and now it appears 9
that the direction that you're taking seems to point to --
10 let's use those test results and the coinsideration of all 11 of those. elements you just mentioned and extend the 12 qualification of that cable for some period of' time.
I 1 31 don't know how effective that is going to be, and that is a
14 my problem?
r 15 MR.-SLITER:
When we reinterpret test data --
16 when I=say that, I mean reanclyze it.
We're talking about 17 a measured environment which is valid, and we are also 18' being very careful to address any significant aging issues 19 that have been brought up by research over the years.
20 Those items are the places where there could be 21-substantial differences in one-answer over what we got 22 originally.
We'll address both of those.
"at
- v main (vj -
. 23 answer goes back to what you broucht up.
You r..id you 24 don't undert tand how that singi-test tells you
' J
. 25-everyth? 1g.
My only response is the one I said a momet.t p.
-[
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32 p
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1
-ago, that'it is not-the only way we can qualify cable.
l
?
2' -Qualification includes all of the good features-I talked 3
about, done according to industry practice, and one of i
1 4.them-is cable installation and it needs'to be done 5
properly.
So I think t cable-test is just one element of
~
6 a good qualification program.
7
~MR. GARDNER:
J.B. Gardner, consultant.
I.Was 1;j 8
going to add another> word of clarification that micht i
L 9
help.
Test qualification, EQ procedures consists'of two 10' t5uns.
We make a device look old, 40 years, and then we' L
11 ' test it.
Now when you make a device look old, you go L
(
12
.through.some routine of pre-aging, which you.think is good 13 for 40 years under certain assumed conditions.
It's good
-14 for 100 years under different assumed conditions, or 20 15 yeare under other assumed conditiors.
That is all in L6 equivalence.
So what George is talking about, okay, we f'
did it for'40 years, we think, sometime ago.
But.we get 18 new data now and we say that wasn't 40, we really tested
.19 - it for 80.
So that is the concept of how you extend a 20- qualification.
I like to call it qualification extension, 21 not requalification, because requalification brings to 22 mind doing the whole smear and testing, including
(
.23 everything else.
But the extension simply means you use a 24 test as it was, but you use the condition as it is now
,25 revealed rather than as it was assumed.
That permits you
m Idh
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-to have a different requalification for productive years-t 2
of successful operation.
i 13.
I'd like to comwent'on one thing, George.
In-4 addressief vnis-quantion of using prequalificatien data, gq i
5 as you realize, the plants have been qualified and are 6-under three different sections.
The o?dsr plants were r
7 permitted to qualify.without pre-aging, ana I think e
i 8
therein lies a good question as to how you demonstrate a 9
cable which was never pre-aged as part of~the-10 qualification test.
They can now be proven to-be s
11: suitable, especia11y'most of those old cables that are not N
x (,/ -
12 even made today and are not available.
13 MR.-SLITER:
I agrue with you, and that is one of 14 the main things we need to look at in the industry report
+
I 15-and that is being examined, of course.
On what basis da 16 you make the-judgment that you have demonstrated that you 17-do not have a cable that has aging effects that could give 18 you a problem?
19 MR. BLOCH:
Peter Bloch from NRC.
I wanted to 20 ask if I understand correctly that uorething is not 21 significant to nafety if it would bring down the redundant 22 piece of equipment, but does not cause a common mode
/-
1 23 failure?
Maybe you can comment a little more?
24 MR. SLITER:
There are certain types of 25 degradation, some that could be expected to cause common
.a
t 34 O'~jL 9/
1-mode: failures.- For-example, if two redundant systems both 5
L!
2 went through the same compartment thaf was not found to be 3 -too hot, they would both degrade, crack, n,d there could 4
be a common rode problem in that.
5-Another example of cor. mon mooe would be, of u
a 6
course, the accident environment, which is directly
~
s 7
addressed,.and you just go through degradation mechanism 8
after dearadation mechanism and ask yourself is it i
9 reasonable to assume that you could have 26 of these.
10 affecting redundant safety training?
If the answer is 11 yes, then 1: needs to be addressed in a qualificat. ion
.O..
..G
~ 12-program.
t 13
-The early founders of-nuclear p1&nts, in their 14 approach to qualification, realized there was no way that 15 they could assure that.there would oe no failures of 16 safety related equipment.
We depend on defense and
=
37 redundancy.
An example ot this would be maintenance 18 errors.
If~someone is putting back a piece of equipment 19 anu he gouges off cable, the accident comes along and he 20 fails a piece of equipment.
He did it the same day and 21 that came guy -- it*a not reasonable to suspect he Wott1d 22 have done damage to the other system.
That is known as
(
23 random failure.
If a failure is easily detectable, you 24 see, you can fix it.
ti.
' 25 MR. BLOCH:
Can you have failure which doesn't m_.
NF 1-35-
- s. r; m 33-b' n;
l.' y f 1-cause; common mode failure?
2.
MR ' SLITER:
Sure.
i r
3 MR. BLOCK:
Are those safety significant?
LL, E
4 MR. GLITER:
No, because you have a redundant l
5 system.
6-MR. BLOCH:
You say it takes down the margin-of 7
safety for the operation of a plant?
8 MR. SLITER:
It takes down the aargin of safety.
9 It's not a question of taking down the margin of-e..".ty.
y 10 It's a question of whether the margin cf safety is o
p 11 acceptable in the way'the plant was-designed with its
- ()
12-redundant system, whether it was to insure.an acceptable 13'_ margin of safety.
It's taking advantage.
You're just 14 looking at it from another point of view..You are.taking 15 advantage of the margin of-safety.
You don't' operate your l
16 plant after an accident.
You should chut do"n and repair I
1*/
everything that has been coing wrong.
18' MR. THADANI:
George, I had a similar question.
19-It's still not clear to me what you really mean by the 20 fact that a plant is designed to be aole to talte a single j
21 failure?
22 MR. SLITER:
Yes.
The plant was designed for 23 that, and the very reason it's designed to be able to take
'44
'eingle failure is -- it's not like I'm goint to have a
.\\ ~
25 single failuro.
It's not likely that that would happen.
+
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1 But if that'were to happen, I have back up.
The question 2'
is-are you' suggesting it's okay to change the' likelihood 3-of initial failure,. single failure, and if you change the
)
~
4 likelihood.of the failure in a significant way, then you p
5.
have, in fact, reduced the margin of safety.
6-The next-question is how.significant is'it?.It's 7
not clear to me how you interpret that or what is.your 8
level of threshhold.
9 MR. SIMMSAC:
Bill Simmsac.
Yes, having-been 10 involved with the putting together of NUMARC, it was never 11 intended to screen criteria upon equipment.
Redundancy is n(_)
12 not a reason'for disposing of it.
Just because you have
[.
L5 mean you can get rid of 13 one train versus another doesn't
~
14 both tra' ins.
The criteria is meant to be-applied in the I
15 following manner:
16 If you have eny system to perform that function, 11 then if that equipment is important.enough t'o be looked at 18 with regard to license renewal, it was never the intention 19 to use redundancy as an-argument for screening out
-20' equipment.
21 MR. VAGINS:
Whether it's redundant or whether 22 it's only a single occurrence failure, if it is age
()
23 related, it will be covered by the rule.
There is no such 24 thing as a nonsignificant, age related failure, because it 25 is an indication of the existing age.
There must be
37-1 something aging somewhere else.. To define a single 2
ccaponent age is extremely u'slikely.
You're going to find 3
similarities.
The program has to cover all failureu.
4 I hope that clarifies the issus.
I don't think 5
it meant anybody is going to stop and say we don't care if 6
it fails because this is backup.
We don't want any 7
possible failure.
8 MR. SIMMSAC:
Earlier we began a section -- you 9-had'a slide.up there that showed a main generator and
.10 control switch area being --
11 MR. VAGINS:
No, I said we'd like to have your
-12 opinion, but we'd like to have your thoughts and what theyL 13 should be.
14 MR. SIMMSAC:
If you considered them, is it only 15 to the extent that the equipment ensures propor isolation?
16 For example, on the electrical side.you make sure your 17-station service system is effectively isolated from a grid 18 in case of a problem, so you don't bring down the 19' greenhouse system?
20 MR. VAGINS:
Yes.
I personally desire that we go 21 further, but I think what. the NRC is proposing is if those 22 systems fail or interfere with our safety system or
- f^'
23 prevent a system --
i-24 MR. SIMMSAC:
So with regard to the switchyard in n
25 Yankee's case, our transformers are separate from the
.. ~.
R
~
I..
38 y
s
/3 L.(_)
1 switchyard, but the isolation is still with transformers q.
li and switchyard, and the screening is not, but station 3
service transformers and.their isolation equipment are.
4' So that philosophy is what we're using.
If we do it that 5.
is great.
6 MR. VAGINS:
It also stands to reason if we 7~
determine indeed transformers out there are aging, you're
. going-to'look at them.
If your switchyaru. go down, you-l 8
9 don't want loss of off-site power.
I assume you're going 10 to do something about it.
L L
We're looking at it up to the-l
)'
12 extent that the controls effectively produce a reactor i
u L13 trip and isolate a steam system properly.
It's an 14 economic conversation.
So, I guess based upon this y
l 15 interchange, the interpretation in the phrase in Section
- 16 3C-1, where you can make a definition to prevent or 17 mitigate a consequences, this is the flavor in which you
~ 18 mean'that phrase to be used.
19 MR. VAGINS:
If you sat in on the screening 20 section yesterday, you would know that there was some 21 discussion about broadening it t; this year.
That is where I want to make
- f')
23 the clear distinction between an initiator that could have U
24 ramifications in the safety of the system, or rather l
25 things just being a pure initiator that some equipment j
1
3p 39 7
(S
)
L ~' '
l-brings the plant down.
[
2'
.MR.-THADANI:
I think you make a valid-point.-
3 You-used a good example.
You-may have hundreds of 4
different ways you can trip the turbine, and it might not 5
be reasonable to, let's say, dig into'each one of those l
6 ways that.the turbine can be tripped.
And let's control-7 all of'that, because if you really have a significant 8
problem, you ought to see it pretty quickly, I would 9
think.
10 on the other hand, I think as you noted, the trip 11 is a very important function and can help mitigate certain l- (D Es_).
12-types of events.-
We ought to focus on that function.
I l
13 agree with you, a difficulty comes in.
But there may be 14 some other areas where certain initiators may be important 15' and those systems may not be classified in the classical c
16 exception as mitigated systems.
What do we do with those?
17 I think the conversation, particularly yesterday, 18 that we had'was certainly helpful to me, and I think'it 19 will force us to look back through that issue a little 20 more carefully.
As you see, we're doing a lot of soul
-21 searching and we want as e.uch input as possible.
We're 22 not looking at it too closely from the age viewpoint
)
]
23 because the challenges are not severe.
24 But again, we're not looking at them.
Therefore, 25 the question now becomes strictly one of license renewal.
t
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We're not looking at'them.
Are they aging and can they.
2.
cause more challenges than we'd like?
That is one'way of J
3 looking at that.
The other way is maybe challenges will-4 increase, but they aren't significant.
Thic is the kind 5'
of input we need from you guys from outside.
6 MR. NEIL:
Karl Neil, NI:C.
On the switchyard, 7
I'd like to make one comment.
In loss of off-site power, L<
8-the. reliability of the switchyard has to be. maintained 1
9 from the aging standard for a renewal period.
My. question 10 relates to.has there been a number?
11 We've heard it often enough here in the last two 1
(
12 days, the philosophy and the conceptual rule with respect 1: '
13 to the scope of what is required.
In other words, the 14 philosophy says we'll give credit for ongoing programs.
i 15 The most recent speaker from Yankee pointed out that he
-16 would'like credit for ongoing programs, ongoing effective s
17 maintenance procedures, things likes that.
In terms of
- 18. ongoing programs that the NRC administers, we know what 19 they are.
I don't think we're going to have much 20 difficulty giving them appropriate credit in the rule and 21 addressing that.
But in terms of licensee programs, I see 22 some difficulty in how do we incorporate it in the rule
'(~%.
23 provision so that licensees can take credit for their 24
. individual programs?
My question is what are the 25 suggestions with respect to specifically, how do we do
U I
41 t
'b
- ,m ;
iA 1 -thisLin the rule?. How would you suggest we. Write the rule t
2 so that licensee programs can.be given credit for?
3' MR. VAGINS:
I think the questien was pretty 4
clearly presented.
Does anybody have an answer to it?
5-
~MR.-DAY:
Mannie Day, NRC.
I had a question 6
along tho'same-lines.
How many of these programs that you 7
have mentioned are tied to industry standards?
Or are 8
they just programs that exist at Yankee?
9 MR. MCCOY:
Where there is industry criteria for
.10 programs, that criteria is utilized, as I mentioned, in 11 battery testing and things like that.
But a lot of the
. o) h_
12 programs are based on our own experience and feedback.we 13 get, such as circulars and notices that we factor into our 14 maintenance programs.
15 MR NEIL:
Karl Neil, NRC.
I-think that was 16 exactly what I had in mind.
If there are some standards 17 that.we could refer to, then we could list those in the 18 consideration and include them in the rule somehow.
I 19 think that would be an easy way of handling it.
But if 20 you're-talking about a specific plant procedure in 21 individual plants that are all different, it's going to be 22 more difficult.
I think if you want credit for those,
()
23 you're going to have to address them in some kind of way 24 in the rule, and I don't see my way clear to doing that at 25 the moment.
If I sat down and wrote that part of the rule
....r,,
~
7 42 1.right now, it wouldn't flow easily.
2 MR. VAGINS:
I don't see any' simple way to handle 3.that.
It would;have to be, since each plant would be 4.
different.
We keep addressing and discussing the 5
uniqueness of our plants.
But I don't see any way to 6
submit a-program for approval by.the NRC as part of their-7 relicensing basis.
8' MR. ROSA:
Faust Rosa, again, NRC.
I might offer.
9 a suggestion to:the industry.
There is a pretty strong 10 economic incentive to keeping a plant operating.
Failures 11 like main transformer failures, unit transformer failures, 12-suitchyard failures, these all impact the operability of a i
13 plant-from-an economic standpoint.
The rule might address 14 the level of operability of a plant as a measure of the 15 programs within the plant for keeping these things in a 16 reliable-condition.
17 MR. VAGINS:
That is something ot course that the-18 agency has been playing around with for a long time.
- But, 19 again, we'want to make sure we don't infringe on the NRC's 20 function, safety.
It is their interest, yes.
A really 21 safe plant doesn't do anything.
It's very safe.
It's 22 there.
23 MR. HINGLE:
Bill Hingle from Yankee.
I'd like 24 to comment just a moment on the use of existing programs.
25 I think Karl Neil was questioning that.
I think in some
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-cases you can credit programs which meet specific criteria 1
~
2: -and that has been proposed in screening methods, to apply t
3-those~ criteria to the evaluating of programs we think we 4
have in place to cover certain pieces of equipment. -Those si 5
run something like this:
The programs document, approve, I
. and routinely implement in accordance with those 6
7 procedures._ If a program assures all components of-8-
significant safety functions, or aging is addressed, _and s
9 if.the programs. establish the acceptance criteria and 10 requirement for follow-up action.
11 So what you could do is establish criteria that
- )
12-have to be met that wouldn't be produced in a document.-
1
,2 All the information is on the application.
We would-
- /
14 propose that we would have that documentation.
In other 15 words, we have to begin through satisfying ourselves that 16. we. meet those bases, and that could be audited.
It seems 17 to me that you could write it in your rule like that and 18
.it would be audited.
19 MR. THADANI:
Let me, for the record, at least, 20 say that industry's responsibility is more clearly safety 21 as well, and the second part of NRC's responsibility is 22 safety, yes, indeed.
But after a certain level of safety, 23. we do have to take that into account.
So I think it's a
{
24 little bit more than what we stated earlier.
We can't 25 just go beyond our basic level of safety without proper
h r
44 (j
I; O 1-consideration to cost.
2 MR. VAGINS:
I want to reiterate what I'said, and 3
that is that in no-way did I. intend to say we're not 41 interested in operability.
I said how to measure, how to 5-interpret operability, again, from the viewpoint of 6
safety.
Obviously, the prime responsibility for safety' 7
lies with the owners and utilities, not with the NRC.
So 8
obviously, you guys are concerned with safety, too.
There 9
is no such thing as a utility not concerned with safety.'
10 I'm just kind of curious -- as things go on, t
11 people talked about monitoring methods.
How many 12 utilities out there right now use thermographic 13 inspections of control centers, you know, control centers, 4
14 circuit breakers, et cetera?
Yankee went up.
Are there 15 any other utilities here?
That is kind of interesting.
16 I suggest that maybe utilities ought to think 17 about tha t'.
For' instance, having plants have phenolic i
-18 boards.
You-talked about mild environments.
I have a 19 couple of-electrical radios that go back 30 years and 20 other things that are sitting in my house which seem.to be 21 in a mild environment, particularly if you don't have 22 children.
Phenolic boards, I wonder how many people are 23 looking at them.
It's been a very good exchange, and I 24 would like to keep going.
Are there any other comments?
25 Mr. Aggarwal has some comments he would like to make.
q 45 i
7-..
1.
MR; THADANI:
'I recommend we take:a break and 2
come back.
Let's make sure the fccus of'this session is 3
clear to everybody.
I'm not looking for any input from 4
you on the issue of source term.
Whether we're going to 5
change a source term for license renewal purposes or not 6
is a separate matter.
You're certainly free to make 7
comments, but recognize that I'm not looking for feedback 8
on that issue.
Other than that, why don't we take a 9
break.
I know there is lot of interest, but'let's take a 10 break for a-few minutes.
We'll hear from you soon.
L l
11 (Short recesc.)
i p ;p I
ks 12 MR. THADANI:
Satish raised some stimulating m
J 13 questions, and I know there were a lot of people anxious L
14 to respond to those questions.
George, you wanted to i
15 start out?
16 MR. SLITER:
Satish, one of the main responses 17 I've heard. over and over --- I won' t dwell on it -- is that 18 almost all the issues you raised in your comments have to 19 do with now issues and they should be handled in the now 20 environment and not in the plant life extension.
I must 21 point out that what was in your conversation, I felt was 22 addressed in my presentation, describing how the industry
. ;,- m
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23 addresses mild environment equipment, balance of plant 24
. equipment, important to safety, et cetera.
I think you 25 should rest assured that the industry approach to life
4 6.-
r I
fsy 1
extension of electrical equipment has come up with~a 2-screening process which should be assurance to-you from 3 -that for life extension at that mild environment equipment 4
and equipment that is important.
5 The safety in a plant will be' looked at, again,
'6 with respect to identifying significant aging mechanisms 7
and assuring ourselves and the regulator that they have
'I 8
been adequately handled.
So it's indeed another 9
opportunity for the NRC to make judgments on adequacy for 10 those programs for life extension.
11 MR. VAGINS:
Any others?
We have one more
-(,)
12 scheduled speaker, Mr. Gardner.
4 13 MR. GARDNER:
I'm J.B. Gardner, consultant.-
I 14 have been involved in cables for some 40 years and on i
15' nuclear application of them for about 20 of that;.on the 16 manufacturing side the last 9 years as a consultant.
All 17 of my remarks are cable crio.
,d.
I'm going to try to hit 18 points-that may have been o:. red or sidestepped by i
19 previous speakers.
20 Age related degradation, aging effects, as I'd 21 like to call :L t, are the name of the game and relative to 22 the rule that is being considered.
There are a number of
.()
23 mechanisms that are described there and I would like to 24 suggest that it might be good to name the mechanisms in 25 the rule, simply to get the NRC and the utility industry
~. - ~,.
r 47-f~
t 1
talking or addressing the same terms so that new worms-1 2 : don't get picked out of the can unexpectedly when people-3.-go for extensions.
But if they're enumerated, they should 4 Hbe segmented into those that are pertinent to different
)
1 5
norts of materials.
I think it is very different from-6' those important organics which may be very different from 7
those that are-pertinent to electronics.
I think just to 8
put down the shopping listipretending that they all 9
pertain the same thing to all would be very misleading.
10 That brings us now into -
oh, there is an 11 omission to that which certainly is pertinent to cables 0)-
(_
12 and to other things, too, because I see 100 percent 13 humidity in number. specifications for plants, and I 14 believe that moisture, as George pointed out, is very 15 definitely an age-related mechanism of failure which has 16 not been addressed and should be in the industry both now 17 and later.
L 18 Common cause failures is the driving agency for L
19 -qualification.
This is-noted in both 323 and in 189.
So 20 I think that is the thing that we should all keep in mind.
l L
21 That is the name of the game in terms of prime effects on 22 safety.
You can't talk about common cause failures
))
23 without thinking about what is the failure mode that we're 24 looking for in the common cause.
That is a wild English 1
l' 25 expression in grar r.
But anyway, I think the point L.
.. C.
l 48 1
\\>
l _- should be clear.
We should be thinking of common cause 2
failures._ To do that, you have-to think in failure modes.
3' To do'.that properly:in the case of cables, we have, both 4
now and in the_ future, a problem that it isn't really 5
cables, but cable systems which connect all of-these 6
active elements in our plants together.
The industry is^
7 way short, and I say the industry, IEEE'for. instance, in 8
addressing all the connections, interfaces of many kinds, 9 _ which are necessary for the cable system to work.
10 Again, this is both a new and a future issue, 11 Whether you want to then disclaim the thing as being a
)
(-:
(_);
12 concern of extension, I'll mention that a little later.
13 I have a real concern because there ar a many open-l 14-issues in qualification of cables.
These have been very-15 well pointed out in some Sandia research and reporting.
16 Some of those have also been reported recently-in the IEEE 1
17 studies, and the work that is going on both point out the L
18 open issues, as well as point out how some of them can be 19 addressed.
I think that is a very constructive way to go.
20 Again, it's sloping over between now and future 1
21 concern.
But the question I have with much of the work is L
22-that not only is it just focusing on cables, but there has I
L ;
)
23 been a lack of operational requirements being 24 realistically described.
Going back in history, the 25 operational requirements that were put in the
~..
49 r"
.I
~
i L-1 specifications to cables suppliers were grossly inadequate 2.in 11~ght of present day technology in knowing what the 3
systems require.
And this is the case again.
4 One could consider it a new issue, but certainly 5.if we are going to delve into new technology, new signs to 6
free research to help solve the problems, the question 7
comes to mind, if we use new research, do we use-the other 8
products and research?
Say to yourselves we need to 9
address all-of the aspects that research turns up, not-10 just the goodies that will help us follow through.
11.
That is an ethical side of what Mr. Aggarwal was 12 saying.
.If we use some benefits, do we also have-the L
13-obligation to use all of what the research is turning:up 14 in the. light of life extension?
I think the bottom line
- 15 then of'what I'm trying to bring to light is that EQ 16 extension is'the name of the game for the cables, and much 17 of the electrical system follows along the lines that 18 George.Sliter pointed out so well.
This focus is on 19 common cause failures.
It gets into the system and all of 20 the modes of failures which a common cause might inflict.
21 Turning now to the rule, I've mentioned already 22 the degradation mechanisms being mentioned therein and 1
' ' ['T 23 that they should be segregated.
The other is that I think
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j 24 the rule would be very helpful if you mentioned in it L
25 something about relation of equipment qualification, J
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x_,1-1 because in the electrical system, this is the name of the:
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game.
I see very little, if any, mention in the rule to q
3 -this key element.
For the moment, I think that will-4 conclude my remarks.
Thank you.
5 MR. VAGIN8:
Is there anybody who would like to 6-comment on that?
My general comment, of course, is that 7
emphatically, no, we are not going to ignore the negatives 8
and emphasize the positives.
That is just not in the k
9 game, and NRC will not do that.
But as I mentioned to you-a 1
10- privately and as I'd like to tell the audience, in some
[
11 sense, negatives are tomorrow's positives.
)
12 What do I mean by that?
We have a system now t
13 which is in place.
It says you're good for 40-years.
I'm
- 14. not going to say whether it's correct or not.
That is 15 another issue.
Right now it's-in place.
If you want to-16 use a positive to expand it, you have to prove your case.
1)
If we find a negative to challenge today's rules, we're 18 going to change it today.
We have to find it.
We have to 19 prove it.
We have to make sure it's true.
Rest assured 20 that is our mission in life.
21 One of the biggest missions of the NRC -- and by 22 the way, the mission of the Office of Research that was 23 put into statutory words in the Organization Act of 1974 24 is that the Office of Research will do confirmatory 25 research.
So one of our biggest missions in life is to
~..
51
'[
ym
'Ay,$.
1 say these are the rules in hand.
Are-they any good?
2 Prove'it.
Unless we get completely out of the budget, can l
3 you tell us -- which Gramm-Rudman is doing to us today --
4 we would-like to solve _the probless and we are going to 5 -within whatever possibilities of funds we have.
But I 6
just want to emphasize that again.
No, we're not going to 7
ignore the negatives.
It is our job to look at the.
L 8
negatives and to make sure they do.not impact safety.
9 It's' the responsibilities'of plants and_the owners.
It's
-10 their first responsibility, and they are primarily 11 responsible for safety.
f'N s-12 So I think that is true.
As far as'how slow we 13 move, well, sometimes-it's hard to prove and sometimes it 14 takes a long while to do it.
But I think we have a track 15 record of eventually doing it.
If we can find something 16 which needs immediate safety action or immediate' safety 17-. concern, we will act immediately.
That doesn't mean 18 shutting down plants, by the way.
Sometimes we can handle 19 the problems in other ways, as we did with the pressurized 20 thermalshock issue.
21 Are there any more comments to either Mr.
]
22 Gardner's comments or Mr. Aggarwal's comments?
23 MR. FARMER:
Farmer, NRC.
As you're well aware, 24 Sandia performed the detailed assessments of the source 25 terms using all the latest mechanistic calculational
?'
.s 52 i
L
/~*$
l Q) 1 methods, andithe results came out showing that dose i
l 2
equipment'inside containment is essentially consistent j
1 3'
with=those in the old TID.
That is happenstance,'but that 1
.4 is the way it came out.
So based on that, at-least this 5
time there really is no basis of changing the rules.
If 6
there was any change,.it might be that we look at severe-
.7 accidents and doses are ten times higher than what they 8
qualify for.
9 MR. VAGINS:
Severe accidents is.another11ssue, 10 and the Commission says that it will be closed before 11 license renewal.
Of course, it doesn't remove the concern-
'\\-
12 that Mr.:Aggarwal' brought up of category 1 on plants.
If l
'l 13' we have plants -- if plants have done the equivalency t
14 study, I~think we do have a problem.
I think Yankee knows 1
15 that.
We're waiting to see what they do with the L
16 extension of these plants.
17 Again,.one of the areas most of us deal with l
18 regularly has a great deal to..o with debt.
And the i
.19 professional societies and the IEEE are very active in p
20 looking at aging degradation maintenance methods, et 21 cetera.
I would only encourage them to continue.
We i;
i 22 would love to have a system where we could sit back and 23 endorse industry standards.
That would make it the 24 simplest thing in the world.
So with the professional 25 societies and IEEE, we're able to move to the issue in lu
.o 53-p.
1, time.- That would be one way of addressing it.
But it's 2
pretty obvious that they're not going.to.be able to be 3
exceptiona'lly timely in the next two years.
4 MR. GARDNER:
In line with your last comment, 5
working' group 3.46, EPRI is indeed rushing through some 6
guidelines which I hope will contribute to the general-7. question of plant life extension..
So we hope'that it is l:.
8 of some help to try, of course.
There are many people in j
l 9
this. room that are. contributing to that.
I might add that 10 my observation, unfortunately, is that the rest of the.
11
- IEEE community is not very active in addressing llf%
(,)
12 qualification issues.
'That is the way it seems to be l
l
.13 right now, today.
1-14 MR. VAGINS:
To some extent it boils down to i
15 whose objection is being barred and who is going to lT 16-support whom and who is going to what' meetings.. And in an-17 era of cutbacks and fund restrictions, unfortunately we H
18 get izpacted in professional societies.
But anyway, it 19 still stands as a fact that if we had standards to cover l
20 everything, we would use them.
We have in the past and we l
l' 21 will continue to use them.
Are there any other questions L
L 22 or comments?
Any other speakers?
)
23 MR. BLOCH:
I want to speak briefly.
Peter 24 Block.
I have been a judgs on the Licensing Board Panel L
25 since 1981.
I have worked with experts at my side as we
54 i
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1 judge cases involving' licensing of nuclear power plants.
2 My concern in being here is to think ahead to the time 3
when there will be an application before me and my fellow 4
judges, and I want to speak on' trending.
I want to speak 5
on it because of the Comanche Peak Nuclear Power Plant 6.
case where the intervenors came in and proved the records 7
of the plant were not being trended.
Appendix B to Part-L 8
50 currently requires that you trend the nonconformances 9 ~ that you find in plants.
It's a requirement-that you must 10 learn what is happening in your plant and learn from it.
11 I can't think of any more important a requirement to keep-l l (.
12-a plant safe than to find out what is going wrong and to L
13 learn why'it-is going wrong.
1 14 Even though it's a new issue, it's obviously of l
15 extreme,. great importance when it comes to plant life 1
?.6 extension, because whatever is going wrong:as a plant ages 17 can go wrong in a different way and in an increasing way.
18 If you trend, you'll see those components that 19 are failing more frequently and you'll know what the l
l 20 problem is.
The records will allow you to see what the 21 problem is.
Now whether or not trending'becomes a part of l
22 the plant life extension rule, there is a possibility that n( j 23 it could become an issue in the plant life extension case 1
24 because it's relevant to plant life extension and because 25 it's already part of the regulations.
(
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Just encourage people to consider the importance 2
of good plant records and good analysis-of recbrds for 3--
trending for licensing cases and for_the-safety of the
-4 plant itself..
I'm disturbed that in speaking to people, I l
5 have learned from the experts who-know, that Appendix B ist 6
hardly known to exist'in the community and it's not being 7
enforced.
Nonconformances are not being carefully trended j
8 in many plants, and in other areas as well.
It's not'an 9
easy thing to have a good system that allows you to do 10 that, but my understanding is many plants don't do that.
1 i
11 Thank you.
l
.(
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12 MR. VAGINS:
That is an interesting statement.
i 13 George, would you like to make a comment?
14 MR. SLITER:
I'd just like to point out something 15 -that goes beyond that.
We have to be careful of our i
.16 terminology.
I fully agree with all of the good words you 15 said, and a rule, when it's written, needs to clarify if l
18 it mentions trending.
You've heard arguments as to why it l
i i
19 may not specifically have to be called out:
one, because 20 it's in Appendix B; two, because Yankee has made the point 21 that 1t could be only one element of an entire program.
22 It's probably more important for long term things.
~ r r)
(
23 The problem here is one of terminology, and there 24 are two types of trending.
There is a trending of the 25 actual degradation of a mechanism as time goes on, and
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sometimes we use the word conditioning monitoring.
Note 2
the result in'the record and that is called trending.
3' The other one I think is mainlyfthe one you-4-
talked about.
~It's trending of failures.
It's-important 5
that whatever-decision is made that we clarify what we 6
sean.
The rule right now -- let's_take a look nt it.
It o
7
- says, "A. description in technical basis for a program of g
~8 identifying-and evaluating trending of the effects of all 9
that relevant degradation mechanisms need to be."
10 What are the effects of failure or the actual 11 degradation?
Technically I think you can=make an argument 7-\\
I l -
12-that for many types of equipment, it is not necessary.
ss j
13 Practically it does not make technical sense to trend the 14-aging of it.
For example, for a relay or pressure 15 transmitter that has a three to five year life, you trend i
16 it over six months.
I think you're pretty sure that aging 17 is well controlled because of your replacement.
- However, 18 if the transmitter starts failing, Appendix B is correct 19 in saying you should be trending failures because you have s
20 a problem, whether it be in design or not.
It doesn't g
i 21 matter what kind of problem it is.
So the distinction 22 should be made.
' ' (3 i
)
23 MR. VAGINS:
Let me clarify one thing.
The staff 24 was very heavily thinking in this issue of trending 25 performance.
One ie.;ue we dealt with, particularly in
.. - = -
}
57
[/ Q a_ /
1 aging programs, was that when failures occur, in some 2.
items they occur catastrophically.
Whereas trending can 3
pick up-a performance diminishing and we could note it.
i jg 4
For instance, if_we could trend if we run ISTs and we
+
5 trend.the performance of the valves, the increase of 6
thrust requirements increase friction.
These are items i
7 that we're-talking about in aging mechanisms.
We're not 8
talking about failure-trending.
A failure is not l
9 acceptable, period.
10 Therefore, how do we know how close we are in 11 some instances, and trending might be able to give us that l
h -) '
12-information.
Areas where things can change.
In_other L
13 words, one thing we don't have is a performance right-now.
14 We don't have a performance level.
We are either 15 functional or not functional.
Many times we do have it in 16 some instrumentation, but basically for valves, for l
17 mechanical equipment, and electrical equipment.
What is 18 the proper functionality?
Is it only when it works or 19 should we stop and replace it at a certain point before it 20 breaks.
21 Failure trending is not going to tell you that.
22 It will tell you what the replacement or refurbishing A)
(_
23 period is, but it won't give you the overall picture from 24 an aging viewpoint.
That you can ge,t from performance 25 training.
The staff is continually looking at this.
We
58 j
.i
?T.
1: want to try to prevent any kind'of failure, within 2
significant failures.
We're not going to worry about 3
light bulbs.
4 MR.' GARDNER:
J.B. Gardner.
Just reinforcing a j
5 comment I think George Sliter made earlier and relevant.to f
6 trending, getting to root causes is a very important part 7
of that.
The.NPRD is what I have been looking at in the 8
course of several projects that have been very 9
unsatifactory from the point of view of what I believe.and 10 what a number of other associated people believe about L
11 failures-to wrong equipment.
Trending in that area can be L [(_/
I 12
.your enemy, not your fr'iend at all, unless root causes are really carefully discovered from the diagnosis of 13 14-failures.
Particularly in the cable areas where you have 15 these in phases.
They can be the culprit.
16 MR. VAGINS:
Of course we're all aware of 17 weeknesses in -- you looked at the cause factors.
They 18 are difficult to determine and I'm positive that I've been l
l' 19 told that they are trying to correct that to improve the 20 failure of the cause basis.
A better identification of 21 that is again today's problem.
We know that.
It will
~
22 affect the future, obviously, but it affects us right now.
1
(~
! (j 23 So we're aware of that.
24 MR. NEIL:
Karl Neil, NRC.
The question is on 25 trending.
I made note of it.
It has been mentioned in
~
F 59
(~Y:
1 several sessions.
I've-been in that-industry and didn't 2
want to trend items where-they're going to replace or 3
refurbish.
I'think. George just implied that also.
I 4.
guess I.didn't quite understand why he didn't want to 5.
trend failures in things that you normally replenish or 6
refurbish because it would seem to me that if you 7
replenish or refurbish it, you're verifying and using the 8
right life of the component.
.It might be different in 9
different locations and different applications and 10 different service conditions.
So I never could quite -- I 11 made a mental note of that, and I'd like to hear a J f
(
12 justification for that.
13 MR. SLITER:
I think you misheard me.
I 14 specifically said I agree it makes more sense to trend the 15 failures of the short. life component.
But it makes much 16 less sense to trend its parameter degradation as a i
17-function of time for a long life component.
Long life L
18 components have a tendency -- you don't want to wait for l
L 19 failure to occur, you want to look at their condition as i,
20 time goes on.
For short term components, it doesn't make j
21 sense to trend them.
But it may make sense to trend 22 failures.
)
23 MR. VAGINS:
Are there any other comments or I
24 anybody wishes to make a statement?
25 MR. ROSA:
Faust Rosa.
I noted that earlier on 1
l 4
60 k-1 th's term here and now issue as opposed to a license E extension issue was mentioned.
Drawing on my experience 3
with implementation, I just want to bring to everyone's 4
attention the fact that' appears to be an area where there 5
is likely'to be.some controversy in the application of any 6
license extension rule.
I urge both the NRC people who 7
work on the framing of that rule-and the industry people 8
who are commenting on it to focus on making a clear 9
distinction between the here and now issues, as opposed to 3
10 license extension issues.
11 MR. VAGINS:
I'm a little confused, Faust.
What
- l. p)
$m 12: specifically are you referring to for license renewal, as-13 far as the station blackout rule?
14-MR. ROSA:
We've had problems with implementing 15 the station blackout rule because the rule and its 16 guidance has not been as. clear as it could have been in 17 -some areas.
I think this area of making a distinction-of 18 here and now issues and life extension issues is of 19 importance in that respect.
l.:
20 MR. THADANI:
I think, Faust, you're right.
On L
L 21 the basis of just the comments that we've heard today, 22 it's fairly clear to me that we need to focus our
( )
23 attention on this issue and try to clarify what is meant 24-by today's issues versus future issues.
I think that ic 25 an important point.
I agree with you.
The example you
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1 use in' terms'of station blackout is also a good example.
2 That-says the industry and NRC,.I think, work very hard up 3
front to try to develop guidance for the industry and for 4
individual utilities to. follow.
This. guidance and 5 ' direction would show that they were meeting the station 6
blackout rule.
What some of the audits have indicated is 7
that there might still be some misunderstanding about the 8
intent or what was meant by a license that was put 9
together about the NUMARC and NRC and that underscores.the 10 need for us to be very carefully up front and not to have i
11 these issues coming up and making those ad hoc-decisions
{A(_j 12-later on.
So in that sense, I think you're' exactly..right.
1:
I 13 It's an issue we must focus our attention on because there 14-is enough confusion.
15 MR. VAGINS:
Are there any other comments or 16 questions?
I found the session very stimulating and t
17 interesting.
But if we're at the end of it, we're at the
'18 end of it.
Thank you.
I O
19 (Whereupon, at 11:00 o' clock a.m.
the hearing was
(!,
20 concluded.)
21 p
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2 REPORTER's CERTIFICATE i
L This'is to certify that the attached proceed-ings before the United States Nuclear
+-
Regulatory Commission in the matter oft NAME'0F PROCELDING:
DOCKET NUMBER:
PLACE OF PROCEEDING:
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 report-ing company, and that the transcript is a true i
i and accurate record of the foregoing, proceedings.
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I Official Reporter Ann Riley & Associates, Ltd.
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NUREG/CN564 :
.8NL NUREG 51971 AN.RV y
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OPERATING EXPERIENCE AND AGING SEISMIC ASSESSMENT OF BATTERY CHARGERS AND INVERTERS L
. W.E. Gunther, M. Subudhi, and J.H. Taylor l
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=>a#==rint camai'i'd: marca 1988 Revisions Made: April 1986:
Date Published: June 1988 i
PLANT SYSTEMS AND EQUIPMENT ANALYSIS GROUP ENGINEERING TECHNOLOGY DIVISION DEPARTMENT OF NUCLEAR ENER8Y BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK 11973 Prepared for UNITED STATES NUCLEAR REGULATORY COMMISSION 0FFICE OF NUCLEAR REGULATORY RESEARCH Q
WASHINGTON, D.C. 20555 FIN A 3270
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4-23
'[ mb An inverter manufacturer's representative stated that an inverter capact-ld tor f ailure occurring at one station was caused by the excessive ripple voltage f rom the battery charger supplying the de bus, coupled with. the length of time the capacitor was in service. As a precautionary measure, all capacitors and SCRs in the inverter were replaced.by the utility.
One utility improved inverter. performance by installing cooling f ans on the top of each inverter cabinet.
- - Fuse coordination was cited as a design problem by; a maintenance supervi-sor whose plant had experienced several inverter trips due to blowing the input' fuse to 'the inverter before the fuse in the branch circuit could-operate. - The f ast acting fuses were required by the inverter manuf ac-turer to ensure internal inverter circuitry protection.
- Some of the actions taken by utilities who have experienced inverter cnd
. battery charger failures which affected plant safety and availability were to increase preventive saintenance scope and intervals, replace troublesome equipment, and taprove systes designs.
Improvements in materials and proce-dures also help to reduce the f ailure rate and could explain the shape of the curve (Fig. 4-15) obtained when plotting inverter.and charger f ailures against I
plant age.
l faitisi aging i
Operoflon Effects Increceed PM and l? '(9, Number of Design !mprovemente l
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Follures p
Rondom Folture /
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i 2-3 4
5 6
7 8
9 Plant age ~Yeare l
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Figure 4-15: Battery Charger / Inverter Failure History Failures early in plant life can be correlated to aging by considering the following:
I Electrical equipment is typically installed and energized early in the plant construction process.
It is then subjected to electrical transi-l ents, dirt, extreme temperatures, and other stresses prevalent during the l
construction and preoperational testing phase which could contribute to C
f ailures when loads are placed on the equipment during early plant opera-tion.
Electrical overloads and dirt were two reasons given by an inver-ter manufacturer for equipment failures during plant startup.
Feedback f rom field service personnel to the main office indicated that circuits F
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LCENSE RENEWAL WORKS 10P SESS ON 7 ELECTRICAL SYS" EMS
- 1. ADDm0NAL CRl1ERIA FOR ELECTRICAL EQUIPMENT INCLUDED IN THE E.Q.
PROGRAW BUT NOT PERIODICAU.Y REPLACED
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- 2. ADDm0NAL PROGRAMS TO ADDRESS AGING DEGRADATION OF ELECTRICAL L
EQUIPMENT LOCATED IN WILD ENVIRONMENTS
- 3. PROGRAMS TO ESTABUSH THE INSITU CONDm0N OF CABLES AND COMPONENTS AND THE POTENTIAL FOR FUTURE DEGRADATION
- 4. REQUIREMENTS WITHIN THE RULE FOR ELECTRICAL EQUIPMENT IMPORTANT TO SAFETY
- 5. FUNCTIONAL TESTING OF ELECTRICAL EQUIPMENT AS A PREREQUISITE FOR UCENSE RENEWAL O
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I NRC~ WORKSHOPHON LICENSE RENEWAL NOVEMBER 113-1411989
- SESSION 47 s
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PRESENTATION 1
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ELECTRICAL AND I&C SYSTEMS l-i i
BY.
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. ROBERT R.lMCCOY i
YANKEE ATOMIC ELECTRIC COMPANY u
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l-l ELECTRICAL AND I&C SYSTEMS
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- PRIMARY FUNCTION TO PROVIDE l
POWER, CONTROL, INSTRUMENTATION 1
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- GENERALLY COMPOSED OF SIMILAR, READILY REPLACEABLE COMPONENTS j
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1 SECTION XX.9 1
REQUIRES
- IDENTIFICATION OF DESIGN REQUIREMENTS, 1
FUNCTIONS, AND ENVIRONMENTAL CONDITIONS
- PROGRAM TO IDENTIFY, EVALUATE, AND TREND l
EFFECTS OF RELEVANT DEGRADATION
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FOR ALL EQUIPMENT IMPORTANT TO SAFETY-1
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SECTION XX.9 SCOPE I
UNNECESSARY l
- WELL RECOGNIZED THAT DEGRADATION CONCERNS ~
- s DO NOT EXIST FOR MANY COMPONENTS BECAUSE.OF:
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-DESIGN CONSIDERATIONS
-BENIGN ENVIRONMENTAL CONDITIONS
-INSPECTION AND MAINTENANCE
-REFURBISHMENT OR REPLACEMENT-l l
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- PROCESS NEEDS TO CONSIDER THESE FACTORS SO THAT RESOURCES CAN BE FOCUSED'ON THE AREAS WARRANTING ATTENTION l
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t i-L NRC EXPRESSED PHILOSOPHY i
"Those structures, systems,:and1 components that are effectively cove' red by existing j
ongoing NRC requirements and/or licensee programs, or are not subject to aging mechanisms need not be addressed in the application (and1need not be within the l
scope of the hearing process)."
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ELECTRICAL AND l&C COMPONENTS i
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- TEMPERATURE AND RADIATION EFFECTS ARE i
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e MAJORITY LOCATED IN MILD ENVIRONMENTS l
WHERE TEMPERATURE AND RADIATION CONTROLLED I
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. MAINTAINED / REFURBISHED / REPLACED THROUGH l
EXISTING PROGRAMS l
- EXISTING PROGRAMS PROVEN EFFECTIVE i
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EXISTING PROGRAMS l
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- MONITOR / MAINTAIN / REFURBISH / REPLACE j
- PROVEN DURING ORIGINAL LICENSING TERM
- CONTINUOUSLY UPDATED BASED ON INDUSTRY EXPERIENCE 1
l
- CONCLUSION - RULE SHOULD ALLOW FLEXIBILITY l
TO CREDIT THESE PROGRAMS l
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- AN EXAMPLE OF AN EXISTING PROGRAM WHICH l
l COVERS DEGRADATION MECHANISMS IS THE ENVIRONMENTAL QULAIFICATION PROGRAM l
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DEGRADATION MECHANISMS i
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- IDENTIFIED AND GENERALLY WELL UNDERSTOOD BASED ON YEARS OF EXPERIENCE i
- UNDERSTANDING OF ENVIRONMENTAL / MATERIALS j
INTERACTIONS CONTINUE TO DEVELOP
-THERMAL AND RADIATION EMBRITTLEMENT
-LOSS OF DIELECTRIC STRENGTH
-MECHANICAL WEAR i
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MANAGING DEGRADATION MECHANISMS l
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- PROGRAMS SHOULD ONLY BE REQUIRED
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FOR COMPONENTS IMPORTANT TO SAFETY l
- NO ADDITIONAL PROGRAMS SHOULD BE. REQUIRED l
FOR THOSE COMPONENTS ALREADY COVERED BY i
EXISTING PROGRAMS l
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-FOR EXAMPLE EQ i
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- RULE SHOULD ALLOW FLEXIBILITY FOR l
MANAGING DEGRADATION i
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TRENDING NEED NOT BE REQUIRED UNILATERALLY, EXAMPLES:
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- A PROGRAM EXISTS WHICH EFFECTIVELY MANAGES AGING BY REPLACEMENT PRIOR TO DEGRADATION NEED NOT TREND DEGRADATION l
-SET POINT DRIFT ON INSTRUMENTS l
- A PROGRAM EXISTS WHIGH SCHEDULES l
PERIODIC REFURBISHMENTS INVOLVING REPLACEMENT OF SHORT LIVED SUB-COMPONENTS NEED NOT TREND DEGRADATION
- A PROGRAM EXISTS WHICH SHOWS BY ANALYSIS l
THAT AGING IS NOT A CONCERN IF THE EQUIPMENT l
18 OPERATED WITHIN CERTAIN. LIMITS NEED NOT l
TREND DEGRADATION
-NUMBER OF CYCLES, ENVIRNMENTAL CONDITIONS I
NEED ONLY BE APPLIED WHERE MEANINGFUL OR JUSTIFIED
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I ADDITIONAL ADMINISTRATIVE ' CONTROLS:
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- ONLY APPLICABLE TO SPECIAL ACTIONS NECESSARY TO MANAGE AGE RELATED DEGRADATION IN SUPPORT OF LICENSE RENEWAL:
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- SUCH ACTIONS BECOME LICENSE COMMITMENTS FOR LICENSE RENEWAL j
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SECTION XX.9 SHOULD PRESENT A -SCREENING TYPE PROCESS l
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- EQUIPMENT IMPORTANT TO SAFETY.
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- EQUIPMENT NOT COVERED UNDER i
EXISTING PROGRAMS l
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- EQUIPMENT SUBJECT TO POTENTIALLY l
SIGNIFICANT DEGRADATION i
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ADD FLEXIBILITY IN IMPLEMENTATION q
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SEVERAL METHODS AVAILABLE I
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- FURTHER ANALYSIS TO DEMONSTRATE-i THAT THE PROJECTED DEGRADATION IS ACCEPTABLE THROUGH THE RENEWAL PERIOD l
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- CURRENT PROGRAMS ARE ADEQUATE TO t
ASSURE DEGRADATION MECHANISM DOES NOT IMPACT SAFETY l
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- FOR THE RENEWAL PERIOD PROCEDURAL ENHANCEMENT MAY BE APPROPRIATE
-For example: Trending l
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- MODIFICATIONS TO OPERATING PRACTICES i
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- COMPONENT REPLACEMENT OR REFURBISHMENT i
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