ML19332D369
| ML19332D369 | |
| Person / Time | |
|---|---|
| Issue date: | 11/13/1989 |
| From: | NRC |
| To: | |
| References | |
| FRN-55FR29043 AD04-1-016, AD4-1, AD4-1-16, NUDOCS 8912010082 | |
| Download: ML19332D369 (99) | |
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OFFICIAL TRANSCRIlYr OF PROCEEDINGS l
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i MCDCy Nuclear Regulatory Commission i
i Public Workshop on Technical and I
Title:
Policy considerations for nuclear.
Power Plant License Renewal:
.i Reactor Pressure Boundary l
Docket No.
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SESSION 2 i
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IOCATION:
Reston, Virginia j
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ANN RILEY & ASSOCIATES, LTD.
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NUCLEAR REGULATORY COMMISSION 3
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PUBLIC WORKSHOP ON 7
TECHNICAL AND POLICY CONSIDERATIONS
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NUCLEAR POWER PLANT LICENSE RENEWAL 10 11 o
12 Session 2
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l q S-13 Reactor Pressure Boundary i
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16 Sheraton Resort Hotel f
f 17 11810 Sunrise Valley Drive 18 Reston, Virginia 19 Monday, November 13, 1989 20 1:15 p.m.
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' SESSION LEADERS:
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J. Richardson 4
L. Shao j
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PARTICIPANTS:
7 James A. Norberg, NRC 8-Matthew F. Cinadr, NYS-DPS 9
Edgar I.
Landerman, Consultant 10 Charles Z. Serpan, Jr., NRC l
11 I. Manoly, NRC 12 Joseph McCumber, Yankee Atomic Electric Company 13' L. R. Katz, Westinghouse 14 Cedric L. Child, Yankee Atomic Electric Company 15 William D. Hinkle, Yankee Atomic Electric Company 16 Vik Shah, INEL 17 Peter Stancavage, GE i
18 Jim Chardos, GPU-N 19 L.
B. Marsh, NRC
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20 R.E. Nickell, EPRI l
21 Peter D. Hedgecock, Nutech Engineers 22 Jim Perrin, Public Service Electric & Gas 23 Bill Corwin, Oak Ridge National Laboratory
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24 Gilbert Zigler, SEA /ASME 25 John Nyquist, Detroit Edison - Fermi 1
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1 PARTICIPANTS, Continuedt
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Charles W. Allison, National Board
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Jim Higgins, MPR Associates 6
Johnnie B. Cannon, Oak Ridge National Laboratory 7
Terry R. Woods, TVA j
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Wayne Pavinich, TENERA i
9 Paul Norman, NRC 10 Herb Massie, Westinghouse f
L 11 Peter Bloch, NRC 12 John Brongren, commonwealth Edison
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13 Rhonda Dor.ey, Combustion Engineering t
14 Ron Chrzanowski, Commonwealth Edison 15 Michael Mayfield, NRC 16 Joe Muscara, NRC 17 Art Dtardoff; Structural Integrity Association 18 l
19 1
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20 21 l
22 23 25 l-
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PROCEEDINGS
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MR. SKAO:
Good afternoon.- Ladies and gentlemen, the l
3-microphones aren't working so I have to shout.
Anyone who E
4 wants to speak will have to shout too.
Anybody who wants to 5
speak will have to identify themselves so that it can be i
6 recorded.
7 My name is Larry Shao.
I'm the director of 8
engineering, Office of Research.
Today I'm the chairman of l
9 Section 2, Reactor Pressure Boundary.
My co-chairman, James 10 Richardson, is the director of engineering technology, Office 11 of Nuclear Reactor Regulation.
12 Before we start questions, let me give you a short
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13 introduction related to the issues relating to primary pressure 14 boundaries.
L 15 (Pause.)
16 MR. ERAO:
As you all knove the primary systet 17 pressure boundary must have very high reliability for the 18 operational life of a nuclear power plant.
It is necessary for 19 reactor core cooling during shutdown and serves as a barrier to 20 the release of fission products during accidents.
21 The principal components of the primary pressure 22 boundary, listed here, mainly are the reactor vessels, steam 23 generators, the pipings, pumps, and valves.
Also, there is
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24 some instrumentation.
Maintaining the high reliability of 25 these components for the license renewal period is the thrust
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of this workshop.
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2 Let me briefly discuss some of the issues related to 3
these components.
4 (Pause.)
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NR. SHAO:
Reactor vessel materials in the region f
6 become brittle by neutron irradiation and thus load carrying 7
capabilities --
it loses its toughness and when it loses its 8
toughness, the reactor vessel is most susceptible to operating 9
in accident loadings.
The method for calculating thinning and 10 embrittlement is provided by so-called Reg Guide 1.99, Revision i
11 2.
12 Some of the older reactor vessels have high copper 13 and nickel contents, and they are most susceptible te 14 erbrittlement.
The four factors that a re mont important to 15 enbrittlement -- and these are the four factors, are copper, 16 nickel, neutron fluence, and the irradiation temperatures.
17 In Lddition to embrittlement, the thermal stresses 18 can also cause cumulative damage to the vessels.
Both the 19 reactor vessel internals, the irradiated, stretch, corrosion, 20 cracking, may be an area of concern for certain vessel 21 internals and core sup> ort structures.
22 We have seen many points of degradation.
Here is a 23 list of the degradatior.s.
The first one is firesign stress
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24 corrosion cracking.
Mainly it results from religious stresses 25 and occur at a new band and road transition in the tube area.
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1 1 understand the French have all kinds of problems with this f.(
2 area.
3 The-secondary size stress core cracking occurs at the 4
two sheet crevices and two support plate intersections.
The 5
fatigue crack corrogation was caused by frozen in use.
The I
6 tube donting, which is regressing in diameter is caused by the 7
corrosion of the carbon steel support plates.
The I
8 intragranular attack, the corrosion attack of grain boundaries j
3 9
usually occurs at low flow areas.
Flooding and wear occur the 10 support plate and the anti-vibration member areas.
11 Pitting and wastage occurred in the sludge part l
l l
-12 region above the two cheese.
Lastly, steel tube was prepared 13 up causing a tube failure at Los Anna.
The two-plugging l
14 failure was initiated also by primary stress corrosion 15 cracking.
16 This is a list of potential dsgradation in piping i
17 that should be considered in license renewal.
The BW piping 18
'has experienced intragranular stress growing cracking.
IGSCC 19 is mainly caused by the combination of sensitized material, L
20-religious stresses and high oxygen content and impurities.
21 For the cast stainless steel, the tests at Fermaton, I
l 22 Argonne National Lab and Western National Lab indicate the cast l
23 stainless steel piping loses load carrying capability when aged
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24 for a long time at operating temperatures.
Thermal fatigue 25 also may result from the poor mixing of hot and cold fluids.
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1 Erosion corrosion is a flaw resisting general corrosion of
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carbon steel piping and it has occurred in Surry and to some 3
extent at Trojan.
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4 In the pump area, the pump shafts experience high 5
cyclic alternate stresses which cause cumulative material 6
damage.
Mechanical removal of bearing material may occur due t
7 to long-term pump operations.
The heat, humidity, flow, l
8 pressure and vibration may cause degradation in pump seal 9
gasket and packing.
l 10 Erosion and corrosion of pump internal are caused by 11 local high flow turbulence and chemical attack.
The loosening 12 of parts and distortion of certain compartments may result from 13 long-term pump operations.
14 In the valve area, the valve disk and disk connection l
15 hinges experience high cyclic stresses and impact 1cading due i
16 to valve operation and flow excitations.
This closure impacts 17 may cause mechanical removal of material at valve seats.
The 18
. heat, humidity, valve pressure and motion may cause seal 19 leakage and insulation failure.
20 The full pressure set for valve actuation may drift 21 but that may not be an aging problem.
It's a current problem.
22-Local high flow turbulence and chemical attack may cause 23 erosion and corrosion of valve internals.
Distortion of 24 internal parts may result from long-term operations.
Also, the 25-mechanical removal of material at the valve stem and worm gear
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may occur due to abrasion.
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The valve, disk and seat may be locked which may i
3 interfere with opening or closure.
For motor operated valves, t
4 the bearing may be worn or broken due to long-term operation.
5 The binding torque switch or limit switch may cause losing i
6 control of valve stem motion.
So these are the lists of 7
potential degradations we have seen now and we will see more in 8
the next 20 years if the plants get an extension.
(
9 Do you have any questions on this?
10 If not, we go to the --
11 MR. CINADR:
One question on pumps.
Just as a topic, i
12 pumps just generally wear out and they do not deliver as they
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13 once did.
These are all kind of catastrophic -- these are end-14 of-the-light problems, but there's another category somewhere i
15 between where it's just a worn out pump and it will not perform 16 da it used to.
Is that something that can be found or 17 considered?
18 MR. SHAO:
Hopefully, we'll find out from the IST 19 program.
We have an IST program, an inspection program, and I
20 this IST program should find out whether a pump is worn out or 21 not.
22 MR. RICHARDSON:
I would add to that.
As the pump 23 degrades in its performance, as Larry points out, that ought to
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be picked up in the normal operation of the plant and that loss 24 25 of pump performance ought to be detected and the pump
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1 maintained and refurbished or replaced or whatever.
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2 But I think we would consider that more in the normal 3
surveillance --
4 MR. CINADR:
Normal.
5 MR. RICHARDSON:
Yes.
Not something associated with t
6 life extension or anything.
It's just the normal wear-out of 7
pumps, as you point out.
They don't deliver fluid at the rate-8 that they were intended to and, when that happens, then, as 9
part of the maintenance program, they would have to be i
10 refurbished.
11 MR. SHAO:
For the reactor vessel piping, we have the 12 ISI program.
For the pumps and valves, we have the IST O
13 program.
Hopefully, those would be picked up by these g
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- programs, i
15 MR. CINADR Thank you.
16 MR. LANDERMAN:
Are you asking for comments now?
17 MR. SHAO:
Yes.
l 18 MR. LANDERMAN:
The name is Ed Landerman.
You 19 mentioned on the casting, casting the steel, if they lose maybe 20
-- making a comment on your comments.
You said they lose load L
21 bearing capability.
I would say that maybe that's the way 22 you're wording it, but that is not what happens.
They 23 certainly do not lose their load bearing capability.
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24 certainly have those comparable properties that they had 25 originally.
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MR. SKAO:
But suppose you have a regular toughness, 4
I don't know, 300 or whatever it is.
After 10 years or 20 5
years, constant thermal embrittlement, you don't have 300 6
anymore.
7 MR. LANDERMAN:
You have the same load bearing 8
capability.
9 MR. SHAO:
Originally, you have a bigger margin.
10 That's okay.
Suppose in your design margin you go to one, you 11 may be in trouble.
The original design margin may be ten.
I 12 Even if you lose some toughntss,'you're still okay.
13 MR. LANDERMAN:
I just want to make the comparison 14 that this is no difference in surveillance tests of reactor t
15 vessels.
We know there are changes in properties.
16 MR. SHAO:
I would say the same thing about reactor 17 vessels, but for other things, it may be different.
You don't 18 lose any capability.
Some material, like -- suppose you have i.
19 stainless steel piping.
It can be there 20 years and your i
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toughness would be the same.
21 MR. LANDERMAN:
Okay.
It's just a comment on that 22 te rm. - I think the analogy is more with changes of 23 embrittlement to reactor vessels.
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24 MR. SHAO:
Reactor vessels are no different.
25 MR. LANDERMAN:
Than stainless steel.
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MR. RICHARDSON:
I think another way of saying it is
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2 stainless steels that age are more susceptible to catastrophic 3
failure through brittle failure.
4 MR. SKAO The reactor vessel and cast iron steel are 5
hopefully the same.
Anymore questions?
l 6
NR. CORWIN:
Bill Corwin, Oak Ridge National Lab.
7 Two comments.
One, I notice there was no mention of thermal, 8
long-term thermal aging with respect to the reactor pressure 9
vessel.
I understand that's not currently within our codes, 10 but I know that the British, in their licensing, are including 11 up to a 30 degree C shift, even for modern reactor materials 12 for long-term thermal aging in their pressure vessel.
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A3 Just a comment; I hadn't heard that specifically 14 addressed and I didn't know if that was going to be considered 15 in the life extension process.
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16 Another comment is with respect to the adequacy of 17 Reg Guide 199.
I don't recall exactly how high the fluents 18 limits are in that, that are explicitly addressed by 199, but 9
19 some of the higher fluents plants may very well run off the top 20 end of the scale in 199 and that's -- the higher fluents 21 regions are something which may need to be reinvestigated 22 relative to the rulemaking.
1 23 MR. SHAO:
That's true, because we may not have the 24-data for real high fluents.
25 MR. KATZ:
I noticed you left off the list two l
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components; pressurisers and CRDN.
Is there some reason for
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that?
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MR. SHAO:
No particular reason.
I just say these 4
are the key components.
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MR. LANDERMAN:
One other comment.
It falls within 6
the reactor vessel and piping, which is a highlight, and that 7
is -- it seems to me it should be highlighted.
It's a similar i
8 metal combination.
Everywhere we've talked about similar 9
metal, concerns about casting, reactor vessel.
An area of 10 concern, as it should be considered, would be the dissimilar 11 metal welds that are part of all these compenents or most of 12 these components.
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13 MR. SHAO:
You're saying maybe binatallic welding.
15 MR. LANDERMAN:
Dimetallic, yes.
15 MR. SHAO:
But bimetallic welding hopefully would be 16 picked up also in the methodology, also in the fatigue 17 ntresses, with differential expansion and also methodology.
18 Any more questions?
19 MR. SMEDLEY:
When you're talking piping, are you 20 talking mainly out of the control room?
21 MR. SHAO:
I'm talking about piping, pressure on all 22 pipes.
It can be any piping.
If you allow thermal stress on 23 the surge line.
Recently, we found in many plants they have 24 some kind of high thermal stresses which was not analyzed in 25 the original FSAR.
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1 MR. RICHARDSON:
I might say to you that if you're LJ i
2 going to ask questions or are going to make comments, if you l
3 would stand up and identify yourself and speak very loudly 4
because it has to be picked up by these microphones up front to f
5 be recorded.
6 MR. SHAO:
Any more questions?
7
[No response.)
8 MR. SHAO:
If not, why don't you start.
9 MR. RICHARDSON:
Okay.
Goed afternoon.
My name is I
10 Jim Richardson.
We've put together some seven questions that i
11 we as the staff have te you as industry and citizens. to help us 12 put together the rula.
These are certainly not totally 13 inclusive of all the questions that need to be raised in the i
i 14 area and I'm sure there are questions that you have or comments 15 that you have that go beyond these.
16 The way I would like to operate this is, first, I i'
17 would like to hear your comments on these specific questions 18 and then, after we get through these seven questions, I'm sure f
-19 some of you may have comments outside of these specific 20 questions and we would welcome those comments.
21 But, first, I would like to get through these seven 22 specific questions.
23 MR. SHAO:
Do you think it's a good idea to have a 24 summary of each question?
25 MR. RICHARDSON:
A summary of each question.
t 14 7-1 MR. SKAO:
Well, after we go through each question, A )S 2
we have a summary.
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MR. RICHARDSON Okay. The first question deals with f
4 the surveillance program in the reactor vessel and, of course, 5
Appendix H of Part 50 of the Federal Regulatio.ss have set forth i
6 the surveillance requirements.
However, those requirements are 7
based on the assumption of a 40 year life.
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8 The question that we're raising is what additional 9
requirements should be set forth and implemented to account for 10 life beyond 40 end how should the survaillance program be 3.1 adjuwted to account for that, considering the fact that I
12 surveillance capsules have been removed on a periodic base with
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13 the asnumption that end-of-life comes in 40 years.
14 Is there someone that would like to address that 15 question?
16 MR. SMEDLEY:
I'm Rick Smedley.
17 This Appendix H thing is right in Appendix G, which 18
.means it's in the Reg Guide 199, rev.
2, which is quite 19 conservative.
Now, with modern calculation methods of reactor 20 pressure, do you foresee the requirements being more exact, for 21 instance, the Reg Guide 1.154 analysis and the NUREG 4744 22 analysis, one having to do with the steam criteria and the 23 other having to do with the upper shelf?
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24 MR. RICHARDSON:
As I understand your question -- or 25 your comment, and your question to us is, do we anticipate a
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1 more exact type of analysis for licensing renewal.
2 MR. SMEDLEY:
I'm just interested in the 50 foot-3 pound criteria.
Some of us are going to exceed the steam
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4 criteria of 5061.
CE just came up with a new method of 5
analysis, and I think they put in a proposal, but I'm not sure.
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I can foresee everybody having to go with this system.
Have 7
you considered that in this?
8 MR. SHAO:
The 50 foot-pound criteria is being 9
changed anyway.
We know it's considered in the regulation.
If 10 you have some new data, you can always submit to NRC c topical 11 report.
We can look at it.
r 12 MR. SMEDLEY:
What are you going to change it to?
p 13 That's what we want to know.
24 MR. RICHARDSON:
Well, you're really getting into an 15 area that I want to avoid in this workshop, and that is i
16 operational problems.
17 MR. SHAO:
It is an operational problem.
18 MR. RICHARDSON:
There is certainly a sharp 19 distinction.
We want to confine the rulemaking, as was stated 20 this morning, to those phenomena that are peculiar to the aging 21 phenomena beyond 40 years.
I don't mean to be avoiding your 22 questions.
23 MR. SMEDLEY:
But I also think that you should i
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24 consider before 40 years.
If we go cver 20, then sure as hell 25 we're going to be beyond.
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1 MR. RICHARDSON:
Well, I guess I would like to turn k~~
2 the question around, if I may.
Do you think that the NRC 3
should tighten its rtles and go for a more stringent analysis?
4 Does that make sense from your perspective?
5 MR. SMEDLEY:
I don't think you have to tighten the 6
rules.
I think, as was indicated, you may have to make the f
7 rules more realistic.
8 MR. SRAO:
We realize that 50 foot-pounds is from 9
many years ago.
Also, when you do a Reg Juide 1.99 revision 2, lo and you cannot do the steam criteria, you do it Lora 11 realistica13y, fracture mechanien, perhaps, and you always have 12 e way out.
It doasn't mean you're stuck rignt there.
13 Fifty foot-pounds, we would entercain anything that's 14 more realistic, and for pressure and thermal shock, we can 15 always develop more realistic standards.
16 MR. MARSH:
My name is Tad Marsh.
I'm from the 17 Staff, the mechanical engineering branch.
18 With respect to low-temperature compression 19 protection, there's many things the licensees can do to address 20 pressure maximum, pressure limits, as the fluence increases on 21 the vessel, just one of which is the adjustment of the Appendix 22 G curve.
There are other operational means they can use to 23 reduce pressure.
24 The CE topical report -- if there is one -- or at 25 least the CE methodology, and some of the others that we've P
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3 PORB set point, with respect to using the RHR systems, so that
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4 you indeed have a bigger operational window in which to 5
operate.
Should it be life extension, or if you have problems 6
even before life extension.
i NR. RICHARDSON:
Do we have other comments on this i
a particular question that we have of you?
9 NN. PAVINICH:
I'm Wayne Pavinich, from TENERA.
10 I think the question is talking about the 11 surveillance progrars, not what to do once you have an 12 embrittlement problem, so I think people are missing the boat a 13 little bit.
ASTM, E-10, who had jurisdiction on E-1-85, which 14 tells you how to run a surveillance program, which I believe is 15 referenced in Appendix H, is already taking a look at that, a 16 draft standard, or an outline of a draft standard for review.
17 MR. RICHARDSON:
Okay.
Thank you.
18 other comments on this question?
Can you offer 19 assistance in us addressing this question?
l 20 MR. LANDI:RMAN:
Ed Landerman, consultant.
21 I'm not sure whether Appendix H really addresses 22 annealing.
It does certainly cover time dependency, but this 23 would be a new time basis on any of it.
The comment is whether j
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24 it's covered under Appendix G, but it's maybe something that 25 should be considered.
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MR. SHAO This is a valid point.
Right now, I think i
2 we see annealing as a viable method to restore the original j
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4 so.right now we are trying to develop some criteria.
But we 5
don't have a criteria now.
6 6
MR. HEDGECOCK:
Pete Hedgecock, from NUTECH.
7 Building a little bit on what Wayne Pavinich said, j
1 8
there are a number of us here from A6TH committec E-10.
With 9
respuet to the attnealing, we did revise the standard E-509 10 several years age, and there is some further revision.
We need 11 some guidance in that.
12 We also have a reconstitution standard, for
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13 reconstituting specimens, because one of the problems that you 14 face as you go on in life is that you're running out of sample 15 material which is valid, upon which to refine many of these l
16 analyses that you were speaking of earlier.
So ASTM is 17.
undertaking some of that work already, which I hope will be of 18 help to you.
19 MR. RICHARDSON:
Question:
What is the time frame L
20 for completion of those standards?
i 21 MR. HEDGECOCK:
E-509 is already on the books and is 22 due for revision, I think, a year after next.
I think it's E-23 12 or -13 that's the reconstituted specimen standard.
That was
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24 issued about a year ago.
We need some feedback and practical l
25 experience on that, which will probably lead to revision before
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1 the normal five-year period.
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NR. RICHARDSON:
I guess another question I have f
3 related to that:
Is there a relationship being developed with I
4 some of the foreign countries that are having the same type of i
5 experience?
I'm thinking particularly of the Soviet Union.
1 i
6 MR. HEDGECOCK:
Yes.
As a mattar of fact, Neil l
7 Randall, of your staff, who's a menbsr of that oubermaittee, p
8 mentioned this at our Inst meeting.
We were boping to get an l
9 update on some of the Russian experience.
You mentioned 10 earlier some of the factors influencing the degree of
'l 11 embrittlement, and among them were copper and nickel, as the i
12 constituents of the seats ana weldsents.
The question is about 13 some of the European steels, where they have high phosphorus 14 and sulfur levels.
We have asked the NRC representative to go 15 back to the work that you're doing at Oak Ridge and see if you 16 can come up with some correlations on these elements.
We have 17 some correlations on those, and they were submerged into copper 18
'and nickel being the most significant elements.
19 There's same question that the European data now have 20 to be looked at with respect to the --
21 MR. SHAO:
The Russian reactor has a lot of 22 phosphorus in it.
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23 MR. HEDGECOCK:
They have high phosphorus, in
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24 European steels.
We don't.
-25 MR. RICHARDSON:
Thank you.
1
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1 Mk. KATE:
Larry Katz, Westinghouse.
2 On the subject of annealing --
I'm the chairman of 3
the special working group, plant life extension, ASME.
We have l
4 moved ahead on an initiative on an annealing procedure which is l
t 5
on the docket for the subgroup for repairing and replacements, 6
based on E-509.
That is actively under way in that group, 7
where they're trying to write a draft procedure bksed on that.
f 8
MR. SHA%
Is there an NRC member in this groupt 9
MR. KATZt Yes, there are.
10 MR. CORWIN:
Bill Corwin, Oak Ridge, again.
j 11 A comment that. ties a lot of this together:
Yes.,
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12 there are standards that ASTM either has or is developing, and 13 certainly ASME as well, on how to anneal the vessels, and how i
14 one can follow the natorial properties of the vessels through 15 an anneal.
It all hinges on the availability of adequate 16 numbers of surveillance specimens, which have seen the 17 operating history.
18 Even with reconstitution, it's very likely that there 19 will be an inadequate base for a number of the older plants, L
20 even if they were willing to reirradiate, starting from 21 scratch.
A lot of times there's not the archival material r
i 22 available with which to perform the proper irradiation.
l 23 One of the concerns that's undoubtedly going to fall 24 back on NRC is, what type of substitutions can be made, or if 25 data are not available, how does one make the judgement calls
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MR. RICHARDSON:
Any comments or last questions?-
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MR. SHAO:
Do you want to take'the next question.
i 6
MR. RICHARDSON:
Well, I guess if I were to summarize p
7:
the question, one; I heard that the national standards ASTM is
- 8 undertaking this problem and looking at it.
However, as Bill-9 points.out, we're still going to come up short on surveillance 10 samples, and how does one deal with that?
It's a nagging 11 problem that we're going tt heue to face.
12-Annealing is ced:aa rly one approach that's going to -
~
13 have to be considered.
the FRC and the industry are going to l
14 have to struggle with an annealing criteria.
What is an 15-acceptable annealing criteria?
In fact, as you anneal, how much recovery do you get 16 u
17 and how do you measure that?
Then what do you do post-18 annealir.g with respect to samples?
Do you insert new sample?
L 19-Do you have -- is there archival material available to start a l
20 new samp?ss program that starts the annealed condition.
21 These are problems, of course, that we struggle with, 22 but the feedback I'm getting from you is a focus on improved 23 standards and look at annealing.
Those are the two main points
(-
24 that I got out of it.
25 MR. SHAO:
The next question is related to cast EY
.m g,
e
.,-w.,,y.,.-
,.,,,--,na,,,.,..,,_.,w,--a
,,,_an-
1 1;
22 I
V["'Y 1
stainless steel.
You know, raybe I didn't use the right s
2 phrase, but?the cast stainless steel, after operating for a 3
long time, has a tendency to lose its toughness.
That's one 1
L 4
issue.
5 The other issue that's not listed here is; it's very 6
difficult to inspect cast stainless' steel, so really there are 7
two issues.
It may lose the original margin, and it's very 8
difficult to inspect, so how should we tackle this issue during l'
l 9
life extension or license renewal.
Can somebody say something?
10 MR. HEDGECOCK:
Pet Hedgecock from Newtech.
On the 11 issue of cast stainless steels and.their embrittlement with i
12 aging, it is very much a compositional matter and determined by
.s
-i j-1 13 the chemical composition, the length of time and the 14 temperature at which it's exposed, but there are ways of j
15' culling out a large percentage of the subject components, given l
I 16 that you have some history on these materials.
17
-You can show, by fracture mechanics, what kind of 18 flaw they would tolerate which mignt turn out to be a through-l 19 wall thickness, leak-before-break issue as opposed to a j
l 20 fracture problem.
I think you'can put the problem in 1
21 perspective in an individual component through some such 22 analysis.
I 23 Then, of course, if you are still faced with your
()
24 second problem which is the inspection itself, and there is 25 some work going on, I believe.
You've probably read all the
I 23 l
}
1:
reports that I have, and there is some hope for improved.
2 inspection techniques,-plus ultrasonics isn't the only way one i
'3 needs to-inspect cast stainless.
One has radiography which-is 1
4 not a small undertaking, but it's being done on comp bodies, in 1
5 particular.
6 I think you can handle the problem by history of the 7
material, taking the research data that's been done in this 8
country and in Europe and Japan'on aging and embrittlement of 9
cast stainless steels.
Then looking for the susceptibility of 10 the particular component and the amount of embrittlement that 11 you showed by fracture mechanics could be of concern.
12 If you've done that, of course, you can relate-back L
13 to what kind of flaw size you should be looking for, and 14 hopefully your research work on NDE technique development will 15 allow you to decide what you can inspect for realistically.
16 It doesn't offer a solution, but at least there's a 17 methodology there, I think, that could be'followed.
18 MR. SHAO:
What if some of the valves are made of 19 cast stainless steel?
l 20 MR. HEDGECOCK:
Again, if you look at the valves, I L
21 suspect you'll find that a lot of the bodies are subjected to 22~
much lower stresses than the piping and the elbows, for 23 example, therefore, their flaw tolerance is probably much
()
greater in term of the fracture mechanics analysis.
The only 24 25 concern one would have on pump bodies is the extensive amount
~__
3 i
l 24 1
of post-casting weld repair that may have been done, leaving j
2 fairly high residual stresses.
3 Again, this should be looked at on a fractured cast i
I 4
basis.
5 MR. LANDRUM:
Ed Landrum.
I still want to make the 6
relationship between reactor vessel surveillance and changes in 7
properties of the castings.
Certainly, there are a number of 8
attempts and work on getting that kind of data, but I think 9
it's minimal compared to the number of plants out there.
10 I could say, originally, on reactor vessels, the 11 intent was to use a correlation monitor material and not an 12 induced surveillance and get a lot of data.
I believe we don't 13 have sufficient data of aged stainless steel castings at the 14 temperatures of operation.
15-Certainly, the analyses can be done, but I believe l'
16 it's with limited information.
When you asked what 17'
_ uncertainties and what measures, and I'm saying there's a need 18 for additional data on the effect of aging.
We're talking 19 about a time dependency.
We're talking about another 20 years.
20 We're talking about a lot of parts being taken out of service.
21 It seems to me that that's the kind of measures that 22 the NRC ought to be able to implement, to get that data and
.23 have a feedback cycle, just like you do with the surveillance -
24
- the reactor vessel surveillance stuff.
25 MR. SHAO:
Any other comment?
25 i
i 1
.1 VOICE:
I read your question slightly differently.
I 2
said,:I read your question slightly differently.
I think the 3
question you're asking ist is a change in fracture is 4
sufficient to change your inspection, your current inspection t
5 requirements?
I think that there are bounding analyses would 6
tell you that the answer is no.
7 A loss in toughness, the worst case that we would 8
expect, wouldn't change your present Section 3 inspection 9
reports.
Therefore, you would probably need to do very little 10 in the way of monitoring the -- fracture toughness.
What you 11 really naed to do is to determine that the boundary of 12' toughness which we now use, which is like a fracture of 2 13 deteriorations, is correct.
14 Parenthetically, I'm not sure I understand why.this l
15 is a life extension issue, as opposed to a curve point.
16 MR. SHAO:
I don't read the question the way you read 17 it, but this is one potential solutions.
Any other questions 18
'or any other comments?
{'
19 (No response.)
20 MR. SHAO:
Okay, let me summarize this question here, p-21 Regarding cast stainless steel, the general feeling is that 22 there is not sufficient data.
Maybe some work needs to be done 23 in this area.
The problem is not only on the amount of
(
24 toughness and maybe the difficulty inspection, however, we can 25 look at some of the components out of service, see how they l
i i
26~
()
1
- behave and we can do some fracture mechanics, do some kind of 2
bonding analysis.
Hopefully we don't have to change the 3
inspection intervals.
4-MR. RICHARDSON:
The third question has to do with 5
the in-service inspection and in-the in-service testing
'6' programs.
As you heard this morning, at least on a preliminary 7
look, it is our intention to exclude the in-service-inspection 8
and the in-service testing programs from license renewals since 9
this is an ongoing program that hopefully will detect the 10 degrading mechanisms and take corrective action as the plant 11 progresses through its life, not only for life extension but as 12 the plant exists today.
.i 13 The question that we're asking here is, in your 14 opinion, do the current in-service inspection and in-service 15 testing programs adequately pick up and detect the aging 16 mechanisms that may be critical to safe operation of those i
17 components and materials?
Are the ISI programs and the IST 18
' programs that we have on the books or coming on the books, are 19 they sufficient to pick up the aging degradation such that they 20 do not have to be modified or addressed in licensing renewal.
21 MR. KATZ:
I'm Les Katz of Westinghouse.
There are 22 three groups looking at that question in the industry at the 23 moment.
ASME, special working group, collects for the pressure 24 boundary, OEM for IST and IEEE 3.4 for electrical and 25 instrumentation.
The ASME pressure boundary PLEX group has
i 27 4
7 [^}
1 been in business for about three years and'we so far have not-4,,/
2 recommended-any specific changes in the code to enhance l
'3 inspections.
/
4 However, we do have a lot of thingc on the agenda' 5
where people are still searching for those and one of the 6-things that'didn't occur, there has been, I think, as a result 7
of the findings of the pilot studies, a new ASME group looking 8
into core structures considerably.
There is a subgroup on core 9
structures currently underway as a result of recommendations on 10 that issue.
11 There are some additional inspections being looked at 12 that came directly out of the pilot studies and one of those is l- '
13 maybe more enhanced inspection of surge line for the thermal 14' inspecting and so on, inspection of that.
The modern 15 initiatives _that have moved forward were in the repair area.
l 16 There has already passed a repair procedure for steam generator j
17 2' plugging -- I'm sorry -- sleeving -- which is new, and as I 18
' mentioned earlier, there is a reactor vessel annealing 19 procedures underway and we're continuing to look for issues and 20 either writing them off or making recommendations so as far as 21 I'm concerned, that's a question that still is unanswered, l
22 totally.
23 MR. SHAO:
What about the ISI of reactor vessel 24 internals?
Do they require additional inspections for their 25 license?
Core reactor vessel internal as a whole.
h 28 e
1
-MR.!KATE:
I don't think that you're a direct problem 2
is associated with life extension.
I don't see them that at 3
-all.
I-think and-the ASME believes that the treatment of core 1
4
. structures has not been adequate in Section 11, totally 5-adequate, and it's been emphasized more by the work that came 6
out of the pilot studies -- not safety issues but probably_
.7 economic issues in regard to understanding when these things.
8 may need repair and so on.
I don't think it's strictly a PLEX 9
issue at all on core structures.
10 MR. RICHARDSON:
Bill?
11 MR. CORMAN:
Bill Corman.
I think there are a couple l
12 of aspects one needs to look at in this.
A lot of the current 13 inspection techniques look at geometric changes, looking at-L i
14 flaws, cracks,. thinning, whatever.
There's also the focus that-15 could be applied if it is deemed necessary and necessary in 16 this case I think is an economic justification or how close are 17-you coming to the margins and that is whether or not you can 18 look at changes in properties nondestructively or very closely.
19-I understand that there was a meeting in conjunction l
20 with the recent older reactor safety meeting where a number of 21 experts from around the country got together and looked at l
22 innovative ways of nondestructively examining properties in 23 situ and that may be something that ends up being required.
()
24 Again, it's a question of how much damage can you tolerate.
25 You need to only look at the geometric changes or do you also
. -.. ~. -.
h:
y 4
29
- 1 need to try and assess the property changes in some of-these s. %)
2
. materials like the aged stainless.
i 3
MR. RICHARDSON:.Thank you.-
4 other comments, responses to those questions?'
l 5-Well, if I were to summarize what I heard from the 6
two gentleman, one would be that a number of bodies have been 7.-
formed and are looking at these very questions.
The ASME, PLEX-8 group, IEEE, O&M, are looking at these very issues and the jury 9
.is still out as to.whether the ISI, IST programs need to be 10 changed.
I would read that not so much in terms of-life
'11 extension as changes needed in the program as they exist today 12 for operating reactors.
p&
1 13-So it may not be as much a life extension issue as 14 the need for improvement in ISI, IST in general.
That's at 15 least the flavor that I got frcm what your raaponse was.- The 16 second aspect is, it may be helpful to look at some innovations.
17 that may allow us to look at changes in material properties as L
18 opposed to the traditional way of just looking at geometric i-19 changes in the materials and their behavior in a non-20-destructive way that may give us insights regarding the aging
'21 degradation mechanism associated with materials and this may be 22 worthwhile looking into and again, the jury is out but it may 23 have promise on the horizon.
24 Okay.
Thank you.
25 MR. SHAO:
The next issue is weld overlay.
For those
-~-.
i 30 l
1 people who are not familiar with this subject, it is'a lot of
]
2' IGSCC piping _for repairing these cracks.
Instead of_ replacing
'3.
the piping,:they put a weld overlay.
We believe this, although
' t's_ safe for current operation, whether this weld overlay is-i 4-5 safe for another 20 years, mainly because the examination is-l 6-very difficult and.when you put on weld overlay, the stress 7
pattern is changed.
For some people, they'll even worry about-8 seismic analysis because some plants have so many weld overlay, 9
the stiffness of the piping is changed.
10~
So any comment on this?
11 MR..HEDGECOCK:
This is Pete Hedgecock.
One comment 12 came-from the previous question.
The answer there was that the V.
13 jury is still out and there are improved techniques being 14 developed.
One would hope that they would be applied to weld 15 overlays as they develop.
That-doesn't answer the second part 16 about the stress patterns, I realize.
17~
MR. SHAO:
Aside the stress pattern, there are two 18 types of stress pattern.
One is localized stress ride 19 underneath the weld overlay.
The other stress pattern is 20 general stresses under seismic loading or dynamic loading, l.
21 whether the stiffness of the piping is changed or not.
Wayne Pavinich of TENERA.
I believe 23 that when you do a weld overlay, you have to update your piping 24 analysis.
That's a requirement right now.
I think it's done 25 as a matter of routine; am I correct?
l l
t
(
f 31 1
MR. SHAO:
Have you done that?
g 2
MR. PAVINICH:
Does anyone disagree'with that?
Is 3
that true?- I thought you had to know what the stress patterns
- 4 are and.I'm not sure you know what the stress patterns are'if 5
you do weld overlay, i
6 MR. SHAO:
But usually, we feel -- when you do one or 7
two overlays, it's very localized and you do a stress analysis-8 in this local area and --
9 MR. O' DONALD:
Bill O' Donald.
Just one comment about 10 the weld overlays is that something that should be a cautionary 11
'hing.- When you do a~ weld overlay because of shrinkage, you 12 can create residual stresses at other welds that have
- b s_/.
13-
- previously been stress improved and sometimes those welds will 14 then crack because the residual stresses are in tension in 15
' those welds and it's a good idea to take a look at the system 16 and stretch your leads to the other welds again that are put 17 under tension when you put in a weld overlay.
MR. SHAO:
Okay.
Dr. Mcdonald is also the inventor 18
+
19 of the mechanical device which also -- stress in crack piping.
20 That -- is also true of NRC to take care of cracking the pipe.
21 MR. DEARDUFF:
Art
Dearduff,
Structural Integrity
. 22 Associates.
I believe that NUREG 0313 today requires when a 23 weld overlay is applied that you do go back and look at the
. (p 24 effect of the shrinkage stresses which result on the rest of 25 the piping system and the other weld overlays that are on the p
...-e-yg,
-.,,..-3-.,
--,wy--
,,f-.
,,,.-,--,um-,
,,r..-
,3,,_,.,,
.,,,,-w w- - = --
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-ww-=-www-i-w
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-32 1-system.
So it-is being addressed today from the standpoint of ps
(_
2 the piping integrity.
3 MR. SHAO:
The shrinking stress is one thing.
The
/
4 stiffness isLanother thing.
5 Also, you change the stiffness of the piping.
6 What-do you people thing, the weld overlays should 7
continue for another 20 years or -- get rid of it and replace
-8 Lpiping?
9 (Laughter.)
10 MR. LANDERMAN:
You qualify the word by ending is 11 difficult and I'm sure there are a number of people out there who will keep trying to make that less difficult.
12' 13 MR. SHAO:
-- do a better piping analysis.
Okay, let 14 me summarize this.
15-We can include the weld overlay design by doing two 16 things, by improving NDE technology and-do a better piping 17.
analysis to take care of the residual stresses, weld shrinking 18 stresses and stiffness effect.
19 MR. RICHARDSON:
The fifth question we had was a 20 multi-question, on a number of issues here.
And I will 21 summarize them as a group and then ask that you comment on any 22 or all of them.
23 The first one being that it is the recognition that
()
24 NDE technology over the years has changed, and we have gotten 25-better at it.
i i
33 J'~i j
(d.-
The question is for plants that for years have 1
2-
- started out with an NDE technology that by today's standards 3
was not very sensitive, should we require a'rebaselining, using 4
the,better techniques that are available today?
That is the 5
first question of Question 5.
6 The second being, should the in-service inspection 7
. intervals and the extent of the sampling remain the same, 8-should they be increased or should they be decreased as a 9
licensing renewal issue?
10 Third, considering that with aging, in particular 11 with materials such as cast stainless steel, there is a loss of 12 toughness.
Therefore, should our flaw acceptance standards, i
13 our acceptance criteria if you will, be modified to recognize 14 and account for the loss of toughness?
L l
~15 The next question, again, recognizing the 16 uncertainties in the level of degradation and in the 17 effectiveness of cur NDE techniques, should we impose as a 18 condition of license renewal a requirement of continuous or 19 near continuous surveillance or NDE techniques during the 20-extended life?
l 21 Now, all of those questions have some relationship to L.
22 each other.
There is also some disparity in those questions.
l 23 I invite your comments on any or all of those parts of Question 24 5.
25 MR. KATZ:
Les Katz, Westinghouse.
P 34
- q We very recently addressed in the special working l
g 2 -
group the issue of rebaselining, one of the issues that came 3-up, because many of the reports.that we read on plant life 4
extension, some of the early work,_and we had recommended such 5
a rebaselining.
We put together a task force that looked at 4
6 that, and they came back with a resounding recommendation that a
7 we do not recommend any kind of a rebaseline inspection, and 1 8
think for good reason.
9
'First of all, with regard to less efficient 10 techniques, the NRC in 10 CFR 50.55(a) does require that the 11 program be rated every ten years, and therefore it would be i
_12 hoped that new techniques would be picked.up as a result of 13 that.
We also see absolutely no reason for going back to 100 114-percent inspection, which would be very high radiation effect, 15 on personnel, would be very bad on availability, and in our 16 view would have gained very little new information with regard 17 to the flaw in the root.
18 So we made a resounding recommendation that we hope 19 sticks, that says that no rebaseline should be required.
We 20 amended rules of Section 11 so that what you do in the first 40 21-continues on exactly the way it has been.
22 With regard to ISI intervals, we have also looked at 23 that and although we didn't look at them in any real scientific
()
24 approach, we feel as if the intervals and the sampling is about 25 right, has been successful in covering things, and should also
35 Q
1 continua..
'% )
2 I won't-address the toughness with aging, because we 3
3 haven't look at it.
4 One other point I. wanted to make was that with regard 5-to monitoring, it just was a new change in the code which will 6
ba published I think'in the next edition which talks about the 7
use of acoustic emission, and does allow that, in. lieu of the i
8 enhanced inspections the code now requires when a flaw is 9
accepted by analysis.
So we have already made some inroads.
10 And it is not specifically related to life extension.
It is a 11 now thing which I think is very good.
12 MR. SHAO:
If I understand you right, you recommend acoustics emission?
13 14 MR. KATZ:
It is in the final review process in ASME, 15 and it is allowed now.
It is an option to more, to an enhanced 16 inspection program which is also required if you have to accept 17; by analysis.
18 MR. RICHARDSON:
But that is really not a licensing 19 rule question.
It is a general improvement in the rule.
20 MR. KATZ:
It is a milestone in that it is the first 21 monitoring technique that I know of in Section 22 MR. SHAO:
Also, you recommend, suppose you extend i
l 23 life for 20 years, two more inspection, every ten years?
I 24 MR. KATZ:
We have, yes, the group, the task people 25 worked on that, recommended that it stay just the way it is.
36-f> N 1
.No increase, no decrease, but just about the way it is.-
f Y_)
s W
2 MR. LANDERMAN:
Ed Landerman.
Yes.
My comment falls i
.3 between 3 and 5.
I've commented on the dissimilar metal walls,
-4 and somewhere it doesn't fall out of all these questions.
But i
5 it-does fall out in the sense'of, I don't know whether you want 6'
to call it rebaseline, but certainly a close look at an 7
evaluation of that inspection, because it is probably the most 8.
. difficult.' We are talking about incenel or stainless 9
inspection.. And so whether you want to call it a new baseline 10-with new techniques or an assessment of where we are, I think 11 there is a need to look at that.
12-MR. SHAO:
You mean --
13 MR. LANDERMAN:
Well, a dissimilar metal well,
-14 inconel or stainless.
15 MR. RICHARDSON:
Are you getting at that as a 16 specific requirement for license renewal?
17, MR. LANDERMAN:
It is currently in Section 11.
You 18 raised the question here about less efficient, do we need an 19 adequately, you know, are current inspections adequate.
I am 20 just raising that question, to assess that.
21 MR. RICHARDSON:
But again, that may be a question 22-that is related to operational plans, not necessarily a license 23 renewal issue in itself.
24 MR. LANDERMAN:
Whether it is an additional issue as 25 effective aging, I don't know.
.?
I 37 i
1 MR.-RICHARDSON:
I see.
Okay.
Thank you.
j#~Y O
2' Other comments, responses to this three-part 3
question?
4 (No response.)
5 MR. RICHARDSON:
Well, to summarize this, the 6
feedback that I get is, at least one arm of industry that is' 7
represented within the code activity is saying there is no need 8
to rebaseline in general, that the tan-year inspection interval l
where programs must be updated to encompass new technology as 9
.10 reflected by the code is sufficient.
There iis no need for 11 going back to a 100 percent inspection.
You pay a dear price p
12 for that in terms of exposure and you get little benefit from 13
_it, and that the'ISI intervals, the ten-year intervals and 14 other intervals that are employed, are about right.
They seem
-15 to be working.
So far, there is no reason to believe that i
16 those intervals shouldn't be about right for beyond 40 years.
17 And a final note, that it would be good to take a 18 look at these bimetallic welds, that although I don't see that 19 as a necessary, necessarily as a license renewal issue, but 20 certainly something that needs to be paid attention to in the 21 process.
Okay?
22 MR. SHAO:
This morning somebody raised some question l
23 on fatigue requirements.
The next question is how should we i
24 treat fatigue in license renewal?
25 As you probably know, the ASME curve, the ASME 1
l~
l t
1 g.
l n-38 1
\\
.1 fatigue curve ~is mainly based on virgin materials.
During the T[J 2
operating life the material has seen a lot of harsh water 1
3 environment and high temperatures but there is one saving grace 1
4
-- in the ASME-curve they use a factor of 2 on stress and 20 on 5
cycles.
For that. margin we feel maybe it's good for 40 years, 6
but.what about for 60 years?
Should we use a different-curve?
7 Another question is what happens if the accumulative 8
damage-factor reach one, then what do you do about it?
9 So I invite some comments how to tackle this-10 question.
11 Dr. O'Donnell?
12 MR. O'DONNELL:-
I have some viewgraphs, Larry.
May I L-(
'13 show them?
14 MR. SHAO:
[ Nods affirmatively.]
15 MR. O'DONNELL:
I'm Bill O'Donnell.
I'm Chairman of I
16-the ASME Sub-group on Fatigue so I take the blame for a lot of 17-the fatigue methods that are in the code, and the NRC came to 18 our committee and pointed out that our curves are based-on data 19 in error and their research over the past 10 years including 20 about 10 NUREGs shows that if you tested reactor water you get 21 a lot less fatigue life because of the accelerated crack growth 22 that you get due to environmental effects.
l 23 Of course there is the International Crack Growth l
24 Committee has done a lot of work on that same subject.
25 The NRC has also pointed out that they feel that the
- t 39 A
-1 fatigue life, the fatigue properties are lower as elevated l
2 temperatures and that we didn't take that into account 3
adequately in our. design curves and they have raised a number i
4' of issues, such as the load sequence effects -- perhaps we're
- 5 not calculating the usage factors correctly and it.also is true 6
that our curves are like 30 years old and they need to be-7 updated.
8
.As a' result of that and also some criticisms that the t,
9 code doesn't do anything for weldments that is very worthwhile 10 and that the practice in the industry is that some people are 11 using fatigue strength reduction factors for weldments, for 12 metallurgical nudge effects and other people are not and they LO 13 feel that-the code should make that practice more uniform.
14 There are a lot of issues that the NRC has raised 15 about the adequacy of the design curves and we are working 16 right now to upgrade them.
17 Another one is that for the early materials we only 18 go to 10 to the sixth cycles, whereas vibrations take you to 10 r
19 to the tenth cycles and.besides cycle thermal mixing fatigue 20 takes you to 10 to the tenth cycle so the curves need to be 21 extended for burning materials for their cycles.
22 As a result the Subgroup on Strength of Weldments and 23 the Subcommittee on Design and others worked up the program 24 which I approved the fatigue design curves that are in the code 25 and the Pressure Vessel Research Committee is the research arm
. ~
r-
>lt 40 1-of the ASME code and-they are trying to get this program to j-N g
%-)-
'2 upgrade these. curves underway and it's like a three year L
3
' program that KPRC has just started.
4 I have a couple of viewgraphs just to show you the 5-
-kinds of things.
l 6
(Slide.)
7 MR. O'DONNELL:
This is a graph on a NUREG NRC did 8
showing that sure enough at higher temperatures the fatigue 9
properties are actually lower, whereas there had been the 10 assumption that in the low cycle regime when the material was ill -
more ductile at higher temperatures the curve should be1 higher.-
~12-In reality'the data shows that for ferritic materials and b
\\s /
13 possibly for austenitics as well the curve is actually lower in i:
14 the low cycle regime than higher temperatures, contrary to i'~
15-common sense.. It has to do with thermal strain agents.
3 16 MR. SHAO:
The question is -- I know the curve is low 17 18
-- the question is the factor of 2 on stress and 20 on cycles.
j D
19 MR. O'DONNELL:
Yes, that's a good question and let 20 me address that with this next curve.
21
[ Slide.)
22 MR. O'DONNELL:
This curve shows that if you take l-23 pressure vessel steel A-Clad 33, and you assume that the
()
24 cladding protects it against early crack initiations -- after 25 water -- but that once you get an underclad crack that you lose l.
F i
41
(
1
'the-integrity of the cladding, you can see where the j
2 assumptions are very important in all of this.
This is why we 3
need national consensus standards involved ~in making thwse
-4 assumptions.
1 5
-If you make the assumption that the reactor water 6
accelerates the crack growth once the crack is initiated, you 7
go from this type of-failure code here to this lower failure-8 curve.
This is-the mean failure code for those assumptions.
9' If you look at the difference in life it's like a 10 factor of 5 or so.
11 Now the code put in a factor of 2 for environmental 12 effects so if we were to construct a curve, just a dcsign curve 13 based on this, we would reduce the 20 to a 10.
That would give 14 you a factor of 2 but unfortunately this difference is like a 15 factor of 5 so that if you make those assumptions and you put 16 environmental effects into the curve, you would have to reduce 17 the curve quite a bit, so this is why we are trying to put 18 together this PVRC ASME consensus standards approach to make 19 sure the assumptions and the factors of course include the 20 scattering of the data, the size effects and the surface finish 21 effects in addition to the environmental effects.
22 To get this lower curve we took the crach growth L
23 rates from section 11 for reactor water.
Section 11 is working 24 on improving their -- and this is an illustration of what 25 section 11 is looking at right now for environmental effects on
hv t
42 7y
()
1 crack growth rates.
They are factoring in the cyclic rate 2
effects into this whole thing.
3 The reason I wanted to take a few minutes to present 41 those curves is to make sure that you know that the ASME code b
5-and the 'PVRC are trying to update these fatigue curves and they 6
are trying to put environmental effects into them and they are 7
trying to account for aging effects and to run the curves out 8
to-high enough cycles so that we can do vibrations and high 9
cycle thermal fatigue.
10 MR. SHAO:
Any other comments?
11 MR. KATZ:
One other addition to the ASME worth 12 mentioning, in-section 11 there is a task group on fatigue who 13 are in the process of writing a white paper on fatigue and they.
14 are looking at, you know, what to do about the fact that you 15 may run on usage factor -- and one of the recommendations to 16 come out of that group is that -- it's not firm yet but one of 17' the preliminary recommendations is that indeed if one views 18 actual transients.rather than design phases they probably
(.
19 become free and I think the background incorporated somehow 20 into these options and code, that would be a big help.
21 MR. SHAO:
Anything else?
l 22 MR. CINADR:
Does the NRC consider the usage factor
-23.
of recalculations?
In other words, that indicates something as
~ O 24 you approach one, how many times can you --
25 MR. SHAO:
If you want to sharpen your pencil --
[
p L
i 43 Jf s-1 MR. CINADR:
Does that tell you something?
h:
.2
.MR. SHAO:- If this gentleman tells you that you need 3
I training and you get into trouble and you want to use=X 4
. training and you have some data to back it --
5 MR. CINADR If everyone records that -- this is no-6-
. problem.
1 I
7 MR. RICHARDSON:
I think from a personal point of 8
view I
9
-- if I discover somebody out there sharpening the pencil to 10-push because they are pushing the cumulative usage factor 11' toward one I am going to start getting concerned just because l
12 of the great uncertainties associated with the loads that go 13 into the fatigue calculations and the fatigue properties 1
1 14 themselves.
15 I start getting worried when we need to sharpen our 16 pencils.
That would certainly be of concern to me.
i 17 MR. SHAO:
When you do a design calculation at that l
18
. time the specification gives you a 10 pound cycle -- if you're 19 realize maybe only --
20 MR. RICHARDSON:
I understand that.
It would just 21.
cause me to take a closer look and challenge it at least so 22 that I really in my heart of hearts agree with what they are 23 doing.
()
24 MR. CINADR:
And there will be more of that as time 25 goes on.
44
_1 MR. RICHARDSON:
Absolutely.
I think our job is -
2 going to'get tougher and tougher..
3 MR. SHAO:
Okay, let me summarize this.
4 MR. DEARDUFF:
Art
Dearduff,
Structural Integrity 5
' Associates.
6 I guess I take issue a little bit with your comment 7
-about looking at anyone who wants to sharpen the pencil because 8
you have got to realize that in the original design of these 9
plants the criteria was that the usage factor be less than one
. 10 and most of'these components were designed by the low bidder 11 and so when you get this stress analysis and you tilt the L
12 founding transients and he could take all of the predicted
~
13' transients from the plant, divide that by the allowable _ cycles y'
l
_ 14 for his one analysis and he got usage factor of less than one, a
15 his job was done.
He didn't get paid any more to do additional L
' 16 analysis to show that that usage factor was really zero in many 17 cases, so with just a little bit more going back and-looking at 18 the original design analysis you can show that it-is not a l
19 concern even though the stress report reported a number which 20 many times has made its way into technical specifications --
21 MR. RICHARDSON:
Well, I didn't mean to imply that I l
l 22 or the NRC would in fact reject a design that had a usage iz l
23 factor near one, not at all.
It would cause me to look a 24 little harder -- when one starts to approach a usage fhetor of 25 one it just causes me to want to look the calculations over a 1
m _ =
a w
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45
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' little closer than-I would with a calculation that came in with XJ
' some very conservative back of the envelope calculations that 3
come out with a cumulative usage factor of
.1.
I turn the game
)
4 up a little bit.
5 MR. SHAO:- I think your point is well taken but a lot 6
of things now-is done based on boundary analysis -- very 7
conservative and your usage factor, less than one, that's it, 8
- so that in the license renewal you have to-sharpen your pencil 9
if you want to get out of it.
10 MR. DEARDUFF:
Another observatien is that industry
~ 11.-
continues to address fatigue through inspections.
As you are l:
12-well aware, there's been a number of actual fatigue failures.
!= k ]d
- which have been observed or cracking has b'een observed in
-j 13 L
L 14 plants.
- well documented, backed by data 15 MR. SHAO:
16
- analysis or you do it with good data and actually we'll look at l:
l 17 it.
18 MR. DEARDUFF:
I just wanted to say though that we 19 have to look at the fact we can't just look at the fatigue 20 usage curve, the usage curve here.
There should be a balanced 21 program of analysis with existing curves combined with 22 inspections --
23 MR. RICHARDSON:
Of course, of course, I understand.
24 MR. DEARDUFF: -- and you shouldn't just ask them to 25 use a new peak usage curve.
46
[ j' 1
MR.. SHAO: -Any other questions?
sw -
2
-(No response.)
3 MR. SHAo:
Okay.
Let me summarize-this.
4-on the fatigue requirements, there was a concern with 5-each of the fatigue curves because the fatigue curve was based, j
6 actually the fatigue curve was based on virgin material, not 7
this material.being faced with different kind of-involvement in 8
high temperatures but now ASME PVRC has a three year program to 9
try to adjust these issues.
10 Also, there was some questioning related to whether 11 the original analysis shows that the cumulative damage factor 12 reaches one then they want-to look at the cycle, look at the 7
L 13 analysis, look at the assumptions when they can sharpen the 14 pencil and do a better analysis to show the cumulative damage 15 factor of less than one.
16 MR. RICHARDSON:
The last of the questions that we 17 thought about before coming to this workshop is sort of a 18 change of pace.
We've been talking about non-destructive 19 examination and analysis.
Sort of the last question is, are 20 there any tests that we ought to require to demonstrate 21 operability in terms of license renewal?
22 Now, of course, there are tests under the IST program 23 and others that require some testing.
What we're asking is, is O
e
\\sj/
24 there a need for additional tests to demonstrate operability, 25 vis-a-vis licensing renewal?
~
r
?
47 1
MR. SHAO:- Well, I think the integrity is a-form of' j
2 operability.
I would.say integrity / operability.
3 MR. RICHARDSON:
I guess a pipe becomes inoperable,
'4 it collapses.
Any thoughts?
5-MR. HEDGECOCK:
Are you including tests to determine 6
material condition to actually measure some form of' aging in 7
the material?
'8-MR. RICHARDSON:
Why not?
?
9 MR. HEDGECOCK:
Okay.
If you include those, there is 10 some work going on in ASTM, some wcrk at Oak Ridge National Lab 11 on.an indentation method which is not non-destructive, but is.
12' very mildly invasive, and from it, one hopes that we'll be able
-s 13 to produce actual' mechanical properties.
There's'been some 14 correlation on irradiated materials and papers published 15 already.
This might be applicable to other materials where the 16 aging phenomena are not just related to the radiation.
17 MR. RICHARDSON:
Is this analogous to a hardness 18 test?
19 MR. HEDGECOCK:
It's very much like a hardness test.
20 You just get a lot more information out of the same process-and 21 derive correlations --
22 MR. RICHARDSON:
More than just field stress?
23 MR. HEDGECOCK:
Yes.
24 MR. RICHARDSON:
Okay.
Yes, over here.
25 MR. McCUMBER:
This is Joe McCumber with Yankee l
.,g
-j i
L l
a i
48:
1 1
'L[~'I 1.
Atomic.- I think, in general, as to one of the questions, I V
2 think, that came up earlier as far as rebaseline, I think any; i
3~
. type of test we feel should be done and technically required 4
based on the degradation you're concerned with cannot be tied, 5
necessarily, to the extended life, or licensing,.or'anything j
6-like that.
7 MR. RICHARDSON:
Yes.
I think we fully recognize 8
that there are, from time to time, the necessity to perform the' 9
test to demonstrate operability.
A recent generic letter'that
. 10 we have on the streets really addresses that in spades, and 11 that's not what we're talking about.
It is those tests above 12 and beyond the routine tests that would be associated with
'O 13
. license renewal, to either rebaseline, whatever, to assure 14 ourselves that this is operable for the next increment of life.
15 Yes, your comment is very valid.
16 Well, I guess I would summarize it by the onu comment 17-
-that we got, was that the ASTM is working on some quasi-non-18
' destructive techniques involving indentation to determine 19-mechanical properties, and that this may prove to be a useful 20 tool in licensing renewal applications.
21 Well, we've come to the end of the seven questions 22 that occurred to us.
This list is far from exhaustive, as I 23 said earlier.
24 We're at break time, or very near break time, and 25 what I'm going to suggest is that we take the break, but before
49
(
l we take the break, can I get a feel for -- are there those 2
among you that would like to raise additional issues in this i
l 3
general area of primary system integrity in terms of life 4
extension, keeping in mind that the purpose of the workshop-is.
a l
5 to hear from you where you think we are going too far, or where 6
mk're not going far enough.
Are we straying off of the path of i
/
the real central issue of assuring safety for license renewal 8
in light of the philosophy that you heard this morning, and l
9 that is the assumption that the 2.icensing basis, the current 10 licensing basis is sufficient for extended life, and we need 11 enly concentrate on those issues that deal with aging 12 degradation?
i O
13 So I guess I would like at least a show of hands of.
14 those that would like to extend the discussion, or have 15 something to say beyond what you've said in response to these 16 few questions that we've put forth.
17 IShow of hands.
18 MR. RICHARDS N Okay.
So it seems like we may have 19 a half a dozen or so.
20 MR. CHARDOS:
Jim Chardos of GPU.
It would seem to 21 me to make sense, after the break, to maybe go through the 22 speakers that have signed up to give some kind of a i
23 presentation, and then based on what you hear there, you might 24 want to expand this discussion about the current licensing 25 basis, age-related degradation.
I know part of what I'm going
- t j
f 50
(
1 to talk about, and maybe some others, will touch on that b
l 2
subject of licensing basis, age-related degradation, the 3
significance thereof, and so on.
l 4
MR. RICHARDSON:
Okay.
So let's take a' break, and l
5 we'll be back at three o' clock.
6 MR. sHAot There are a couple of persons requesting l
7 to comment.
The first one is James Chardos, representing the 8
NUMARC/NUPLEX Working Group.
9 MR. CHARDOS:
Good afternoon.
On behalf of the 10
' NUMARC/NUPLEX Working Group, I'd like to make a presontation on 11 pressure boundary and then detail, to some extent, the reactor
^
12 vessel for PWRs.
l 13 I'd like to, before I get started, mention that 14 NUMARC Working Group and NUMARC itself will develop and has 15 developed answers for those seven questions, so we will put l
10 somethir.g in writing in the next week or two, within the period 17~
allotted us.
f 18 (Slide.)
19 MR. CHARDOS:
We had talked earlier today about the 20 reg guides and SERs and Frank Gillespie mentioned words about i
21 industry reports from the -- reports from the industry beitig 22 reviewed as topical reports or possibly part of the reg guide.
23 From our point of view, it's not mandatory that a reg 24 guide be developed for the industry reports the.t we contemplate 25 at this time.
As it mentions, topical reports would be l
I 51 1
(}
1 sufficient given some form of an SER endorsing those reports.
2 A guide will be acceptable with some caveats here.
l 3
In terms of getting something that's together, a benefit from i
4 analysis or something that's developed by consensus within the i
5 Working Group, we've got those reports put together that can be l
6 used for that reason.
If the conceptual rule -- and we talked 7
a little earlier about this in terms of the rule versus what's 8
in the register, in terms of being together on two points, one
{
9 of which is the credit for ongoing programs that the NRC has in
}
I 10 terms of inspection and enforcement.
11 It only requires review for those efforts that have
-s 32 significant age-related degradation.
So those are kind of like 13 two caveats for usage, as well as we talked before and others i
t 14 have about reg guides and not holding up the two lead plants, 15 given their submittals are in the June and December timeframe 16 of 1991.
17 So that kind of gets back to the schedule we saw i
1 18-earlier today in terms of reg guides, and then some more reg 19 guides.
There were two submittal dates of reg guides.
And we, i
l 20 as an industry, would back that given it doesn't, as a last i
21 concern here, effect the lead plant submittals and eventually 22 their review and hopefully receiving a renewed license.
23 (Slide.)
24 MR. CHARDOS:
In terms of specific reports which we i
25 believe address the pressure boundary, these are the four that 4
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we have that just reflect the pressure boundary.
As you can j
'N 1
i s-2 see, there's the PWR reactor vesself the PWR reactor vessel and
{
i 3
then the BWR and the PWR pressure boundary reports.
l 4
These are four of ten reports that NUMARC/NUPLEX
{
5 plans on eventually submitting between now and the summer of 6
next year, with the express purpose of using these as i
7 benchmarks for the industry and for the NRC.
So these four are 8
four that reflect on the reactor coolant pressure boundary, two t
9 of which deal with the reactor vessels.
i 10 As you see, the BWR reactor vessel has been submitted 11 to the NRC in October of this year, and the other ones, these 12 three have schedules which we've already previously submitted O'
13 to the NRC which are all between now and the June / July 14 timeframe of next year.
15 (Slide.)
16 MR. CHARDOS:
Next, I'll kind of go through quickly -
17
- I have an outline of industry report and gat back to the 18 licensing basis and those kinds of issues, as we talked before.
19 The process for an industry report and kind of the 20 format of the two we've already put in, the BWR reactor vessel 21 and the PWR containment, follow the following format.
In terms 22 of a total group for the containment or the reactor vessel, you 23 determine which components are, in fact, safety related and
()
24 safety significant.
25 With that grouping of components or subcomponents,
e i
53 1
you now describe all the plausible degradation mechanisms that 2
apply to this particular component or subcomponent.
It's worth 3
noting here that in the proposed rule, a list -- a number of l
4 degradation mechanisms, and with or without inclusion in the 5
rule and definitions thereof, for each of these reports, you 6
need to look at the mechanisms that, in fact, effect the i
7 component or subcomponent.
Some of them will not and do not.
j 8
The next bullet kind of follows to that in terms of i
9 determining which ones are potentially significant to those i
10 that, in fact, are applicable to the component.
And then the 11 last two talk about those that are potentially significant, t
12 determine if the existing programs for inspection and.for 13 testing and analysis as currently implemented are adequate to 14 bound the age-related degradation within acceptable limits.
15 So that tells you for particular degradation 16 mechanisms if the existing programs are adequate and bound to 17 degradation within limits, then you don't have a problem.
For L
18 those, which is the last bullet, where you may have significant 19 degradation beyond established limits, then you either put 20 together a program for aging management.
21 So that's kind of a -- if you look at a format of the 22 report, the last section of the report picks up the last bullet 23 and tells people, utilities, which ones they think aru t
24 significant, that may be outside established limits and may 25 require each particular utility to put together a program to i
l
S4
(}
1.
address those degradation mechanisms.
2 (Slide.)
3 MR. CHARDOS:
For the four reports I talked about 4
earlier, we've tried to, as shown here, display the appropriate 5
mechanisms or degradations that apply to each of those four.
6 If you look at the BWR reactor vessel, we've listed the six-7 that we believe are, in fact, at play here and need to be 8
addressed.
9 For the PWR reactor vessel, those are the ten or so 10 that apply.
Then down below, for both the PWR and the BWR 11 pressure boundary, there's those five.
Once again, these 12 groups of five, ten or six all come, to some extent, from that 13 list in the proposed rule of degradation mechanisms that, in j
14 fact, need to be addressed when you go through and review a 15 component or a system.
So those are the mechanisms that will 16 be addressed for these reports.
17-MR. SHAO:
May I ask a question?
18 MR. CHARDOS:
Certainly.
19 MR. SHAO:
Why is creep a problem?
Is it the high 20 temperature creep?
21 VOICE:
He didn't say it was a problem.
22 L(R. CHARDOS:
No.
I said that's something we need to 23 address or review and if, in fact, it's bounded, then it would 24 be not a problem.
I just mentioned that.
Therefore, for 25 creep, the answer would be temperatures not high enough;
55 1
therefore, not a problem.
But you need to at least review it f
2 to make sure that's the case and not just dismiss it offhand.
3-You ought to be safe by addressing it ar not addressing it, t
4 MR. SMAO:
An I right, to have creep, you have to 5-have over 150 degrees --
6 MR. CHARD 08:
Correct, but --
j 7
VOICE:
Could you repeat that question?
[
8 MR. SHAO:
The question is he lists creep as an aging i
9 mechanism.
My reaction is the temperature in the PWR is not in l
10 the creep range.
If you're not in the creep range, why 11 consider creep, then?
12 MR. CHARDOS:
only from a completeness point of view 13 so that, in fact, was addressed and dismissed as opposed to i
14 leaving it open and not addressing it.
I 15 MR. SHAO:
But if you do have a creep there, I'd like j
16 to know it.
[
17 MR. NICHOLS:
I'm Bob Nichols from EPRI.
The report 18 that is complete, which is the BWR pressure level report, gets 19 rid of creep completely.
It doesn't even treat it as a 20 plausible aging degradation mechanism.
The report which is in 21 the process of being developed, the PWR vessel, and so far 4.t's
[
22 carried that along as a plausible mechanism.
It may not be 23 there when we get through with the final review.
Is that 24 clear?
25 MR. SHAO:
Yes.
That's why I was very surprised to
i 56 t
i see creep here.
2 MR. NICHOLA:
It may not be there when we finish the i
3 final review.
i 4
MR. CHARDOS:
All right.
Those degradations not 5
evaluated in the BWR reactor vessel and the P and.9 reactor f
l 6
coolant systems and are listed in the outline of the~ review --
7 we talked before about creep and shrinkage, service, wear, and i
8 chemical and biological effects.
9 So in these cases, these three were not as plausible.
10 So we're talking about mentioning being plausible.
At this l
11 point, for the PWR, we're carrying it along as a possible 12 plausible, but in this case, in those three, we've said no, 13 they're not plausible and so, therefore, they're not carried.
14 It's kind of a degree of conservatism here, because 15 how far do you carry it along in the report before you say it's 16 not plausible and, therefore, I will not consider it.
)
l l
17 (Slide.)
18 MR. CHARDOS:
At this point, I'd like to just simply 19-address, if I could, the BWR reactor vessel age-related 20 degradation.
Now, this is a report I mentioned that we have l
21 submitted in October of this year and we talked about --
22 earlier, there were two groups of mechanisms, degradation.
23 Going back to the previous slide, the last bullet was for those
)
24 of which you needed to put in place an age-related management 25 or management program to address age-related degradation for
57
N 1
certain issues.
i(v.
2 This last bullet here mentions that there are, in l
l 3
fact, three of those mechanisms which require a plant specific t
4 management methodology during the license renewal period.
And I
5 these three, as the report outlines, is stress, corrosion, 6
cracking of attachment welds to the reactor vessel; fatigue of 1
7 the CRD or control rod drive return line nozzles for the BWR-2 8
reactor vessels; and neutron radiation embrittlement of some 9
worst case vessel weldsents is a concern for a few applicants.
10 And that last one really is, to some extent, a 11 current day problem for maybe two or three.
It may, in fact, l
12 be a 40 to 60 or 40 to 70 year problem for two or three also.
O 13 So.it's kind of a limited concern for two or three between now 14 and age 40 and two or three or so after age 40 in the license 15 renewal period.
16 But these, once again, are the three that fall out, 17 which a licensee or an applicant would need to put together put 18 a plant-specific program to address these three.
That's really i
19 the significance of this particular slide.
These are three, i
20 but they're reviewing all of them for the PWR.
These are the 21 three for which they have, after review, fallen out that need 22 to be addressed.
They could possibly be outside of established 23
- limits, l
()
24 We talked before about being within bounded limits, l
25 outside limits, and inside limits.
l t
.,,,.m
l i
58 l
()
1 MR. SKAO:
Is the reactor containment considered in 8
2-this program or a separate program?
l 6
3 MR. CHARDOS:
In a separate report for both BWR and
'4 PWR.
At the end, I'll kind of go through the report we're 5
putting out, in terms of submittals, and the BWR reactor vessel I
6 internals and the PWR reactor vessel internals are two more t
7 reports that were not part of the pressure boundary.
8 MR. SKAO:
What about reactor vessel supports?
9 MR. CHARDOS:
That's in the reactor vessel itself.
10 The supports are covered in the reactor vessel.
l 11 (Slide.)
i 12 These are mechanisms which have established programs O-13 for inspection and testing for which the degradation is bounded i
l 14 within acceptable limits.
We talked before about being bounded l
L 15 within limits and those that may be outside established limits.
[
16 These here, namely neutron irradiation, vessel belt t
17 line weldsents, in the majority of the BWRs -- and for a PWR, l
18 LPCI nozzles -- stress corrosion cracking of CRD stop tubes and 19 neutron flux holders, fabricated from stainless steel and 20 subject to welding stress, fatigue of PWR reactor vessel 21-feedwater nozzles, stress corrosion cracking, and fatigue of 22 nozzle safe ends, depending on the geometry, and material 23 selections, fatigue damage of reactor vessel studs, and fatigue
)
24 damage of reactor vessel support skirts.
25 These mechanisms have been reviewed, and the report
^
l i
59 1
mentions that these are covered and are bounded within existing f
()
2 programs for inspection and testing, and are therefore not a 3
problem.
They have been reviewed and been found to be not a
.i 4
problem.
I 5
so this is kind of the second set of mechanisms that i
i 6
were reviewed and found not to be a problem.
7 MR. BLOCH:
What's the criterion for "not a problem"?
8 MR. CHARDOS:
In terms of established limits -- take 9
fatigue on the feedwater nozzles for the skirt.
There are 10 limits established for various mechanisms.
l l
11 MR. BLOCH:
The initial design safety margins were i
i 12 what?
)
13 MR. MARSH:
So you evaluated out to the extended i
14 life, and the cumulative fatigue limits were not exceeded.
Is 15 that correct?
16 MR, SHAO:
Yes.
17 MR. CHARDOS:
On the PWR, you used to have cracks.
l 18 It's in NUREG that periodically, of course, you inspect.
i i
19 There's an internal and an external inspection requirement.
I 1
20 think it's NUREG 0619 that requires you periodically, every so 1
21 many outages, to look at the external PT, internal PT, so l
j 22 that's an established program.
You're talking about
?
l 23 temperature monitoring and those kind of things that address 24 fatigue of feedwater nozzles.
I 25 MR. MARSH:
You put on thermal sleeves?
. -.. - -. - -. -... ~..... - -
)
60 1
MR. CHARDOS:
Right.
Thermal sleeves.
,IC 2
So that's a program that's under way, and it's 3
covered.
4 MR. MARSH:
Notwithstanding the words that the code 5
uses to look at the fatigue usage factor, the fatigue usage 6
curvos themselves, right?
7 MR. CHARDOS:
Correct.
8 MR. MARSH:
You're saying you need the curve.
9 MR. CHARDOS:
Correct, and that's separate, as we 10 heard before.
11 MR. MARSH:
So your conclusion may be changed, 12 depending on the code.
13 MR. CHARDOS:
Yes.
True.
14 MR. MARSH:
Do you have a mechanism for that, to 15 review your conclusions?
16 MR. CHARDOS Well, as part of the NUHARC/NUPLEX 17 working group, we have PNCS representation on the working 18
' group, and we have people sitting on both groups, and so we 19 have feedback from one to the other, so we don't lose sight --
20 MR. SHAO:
Ist me ask you a generic question.
Do you 21 have any designs relating to the vessel?
How do you tell 22 generically that everything's okay.
How do you know you're 23 being independent?
24 MR. CHARDOS:
Pretty.much, in the report, if you look 25 at it and you see "feedwater nozzle" and "feedwater sparger"
[?
L i-61 1
and " thermal sleeves," you go through the various thermal
)
2 sleeve designs, whether it's single-ring, double-ring, welded,
)
3 forced, and you do --
4 MR. SKAO:
But how do you know the design located is 5
the worst design?. Different geometry, different diameter, 6
different thickness, different thermal mixing, how do you know 7
the design you are looking at is the worst design?
8 MR. STANCAVAGE:
My name is Peter Stancavage, fron 9
GE.
10 We did not investigate all 30 feedwater nozzles.
We 11 looked at about 12 of them and took the worst of those, and 12 then we supplemented that by the inspection programs that 13 plants are undertaking and confirmed that cracking is not going 14 on.
15 MR. SHAO:
But how do you create another 60 years 16 now?
17 MR. STANCAVAGE:
Well, extension programs.
18 MR. SHAO:
Another 20' years?
19 MR. STANCAVAGE:
Yes.
20 MR. SHAO:
But you need 60 years.
1 21 MR. STANCAVAGE:
Well, the extension programs say, j
22 every three cycles, one has to inspect feedwater nozzles, and i
I 23 that inspection program would continue throughout the service
()
24 life of the plant, whether that's 40 years or 60 years or 80 25 years.
The basis for concluding -- at least on the feedwater
l 9
62
' lS 1
nozzle -- that fatigue is well managed is inspection more than O.
2 analysis.
Support is good at the other end.
I 3
We looked at a number of other configurations, that 4
the usage factor, based on existing codes, would always be less i
5 than one for 80 years.
i 6
MR. SHAO:
But you analyzed the geometry and came to 7
this conclusion?
8 MR. STANCAVAGE Yes.
9 The report is based on assumptions, and each 10 individual plant has to verify that those assumptions are true.
11 MR. SHAO:
What you're saying is that this is a 12 public report, and each licensee submits his own findings of 13 the bounding.
14 MR. CHARDOS:
Right.
Absolutely.
15 MR. SHAO:
Does that mean you're bounding -- that's t
16 very conservative.
17 MR. NICKELL:
Bob Nickell.
It should be pointed out 18 that one of the issues that fell through to requiring a plant-19 specific management was the CREL nozzles on the BWR IIs.
That 20 happened to be one that fell outside the limits and had to be 21 treated as a special case.
It required that additional plant-22 specific management program.
That's an example.
You can't 23 cover everything by bounding analysis always.
24 MR. SHAO:
If you have a lot of margin, you can do 25 that.
But if you don't have enough margin, it could be very
_. - _.. _ ~ _ _. _ _
i l
63
[
i g
1 difficult.
-x
()3 2
MR. CHARDOS:
So you've really only extended it 20
[
I 3
years, right?
i 4
MR. SMAO:
Yes.
The life expectatcy.
5 MR. CHARDOS:
For conclusions on the PWR reactor l
6 vessel and the PWR and BWR pressure boundary, we mentioned 7
before that those are reports that were submitted on a l
8 previously agreed upon schedule within the next six months or
{
9 so, and those reports will have detailed evaluations,
[
10 conclusions, similar to the ones that I've mentioned here for
[
11 the BWR reactor vessel, and those will in fact be submitted and 12 reviewed and, hopefully, approved by the NRC.
'O.
i 13 As I mentioned before, we're putting out 10 topical 14 reports.
The four that I mentioned were the BWR and PWR 15 reactor vessel and the P-and the B-pressure boundary.
Some 16 of the other ones that either had been submitted or will be 17 submitted are the PWR containment, which went in in the summer 18 of this year, in August.
We had the BWR containment and 19 conteinment cables and class I structures, and the PWR and BWR t
20 reactor vessel internals.
Those make up the 10 reports that 21 the industry plans on submitting.
22 MR. SHAO:
The reactor vessel supports are here.
23 MR. CHARDOS:
The reactor vessel supports for the BWR 1
)-
24 reactor vessel are in the report.
The PWR reactor vessel will
(_
25 address its vessel supports.
The pressure boundary should i
)
i l
64 l
1 cover that.
We have to take a look at the scope.
-]
^
J 2
MR. SHAO:
What about the steam generator supports?
3 MR. CHARD 08:
I have to take a look at that.
I'm not 4
exactly sure if that's covered or not.
I'm not sure if the l
5 steam generators are specifically covered in the pressure 6
boundary for the PWRs.
I'm not exactly sure.
I'll have to get
]
7 back to you on that.
)
8 MR. SHAO:
The steam generators may have an aging j
9 problem, because the temperature fluctuates.
10 MR. CHARDOS:
We'll take a look at that, i
11 That's all I have.
12 MR. MARSH:
I have a question.
13 MR. CHARDOS:
Yes.
14 MR. MARSH:
Back in the earlier slide, you talked 15 about designating some systems and structures as safety 16 significant.
What does that mean?
What are you saying?
17 MR. CHARDOS:
As defined, a component whose failure 18
'would affect the function of the system or the component to do 19 its safety function.
20 MR. MARSH:
Now you're talking about active machine:
pumps and valves, for example.
21 I
l 22 MR. CHARDOS:
Or support plates.
23 MR. MARSH:
So " safety significant" doesn't extend to
(
24 active machinery?
It's only for passive machinery?
25 MR. CHARDOS:
Both.
l
_ _ _ _ _ - _. _ _ _ _ ~ _ _. _. _ _. _ _. _ _. _ _ _ _ _. _ _ _ _. _,. _ _ _. _ _... _ _ _., -
i i
65
~N 1
MR. MARSH:
It does cover pumps and valves?
(b 2
MR. CMARDOS:
Yes.
[
3 MR. MARSH:
I didn't hear any words discussing those.
4 MR. CHARDOS:
I think pressure boundary irs --
i 5
MR. MARSH:
That's all in the pressure boundary 6
portion of it.
I'm talking about pumps and valves, their 7
capability to perform their job.
Active machinery.
8 MR. CHARD 08:
Specifically, like main coolant pumps.
l 9
MR. MARSH:
Not main coolant pumps.
I'm not sure if 10 that's safety significant.
Safety injection pumps, high-11 pressure coolant injection pumps, check valves, those kinds of 12 things.
13 MR. CHARDOS:
Currently, I don't believe we have any l'
14 reports contemplated to cover that.
15 MR. BURTON:
My name la Rich Burton.
I'm with EPRI.
16 The 10 irs that Jim is going to go over shortly, to 17-show you what they are, are basically only in safety class I 18 systems, in containments, for instance.
I realize there is a
{
19 bunch of others we discussed.
The screening methodology or 20 methodology to identify something to evaluate for license 21 renewal has a process such that all systems are evaluated using 22 a very similar basis, looking at effective programs, 23 significance, and so forth, for all systems.
They are not l()
24 generic reforms in a plant, the valves and RHR and LPCI l
25 systems, and so forth.
i
... ~.
I i
66 6) 1 MR. CHARDost Anything else?
(?"
1 2
(No response.)
3 MR. CHARDOS Thank you very much.
4 MR. SHAO:
Anyone from Northern State Power want to 5
comment?
Anybody from Northern State Power?
6 The next speaker will be from Yankee Atomic, Cedric
]
I 7
Child.
8 MR. CHILD:
My name is Cedric Child.
I'm with.Vankse o
)
9 Atomic Electric and we're currently doing the lead plant PWR 10 analysis on our plant -- on our Yankee Plant out in Roe, 11 Massachusetts.
12 Roe is a pressurized water reactor.
As mentioned 13 previously, the pressurized-water reactor pressure boundary.
14 consists of the reactor vessel, which would include the control l
15 rod drive mechanism housings, the main coolant system piping 16 and the main coolant system components such as the pumps, the 17 valves, the primary cite of the steam generator and the 18 pressurizar.
19 Now, all these components are safely Class I 20 components, so, a discussion which really hasn't arisen here as 21 to significance of safety or significance to safety doesn't 22 really apply for the reactor pressure boundary components.
23 They're all safety Class I, they all have significant safety
.I 24 requirements.
25 Now, these -- the next step in the plant life renewal
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process is to evaluate these components against degradation V
i 2
mechanisms and maybe we should step back here we talk about j
3 degradation mechanisms because the degradation mechanisms that j
f 4
we're analysing for are really nothing new.
They've been 5
identified, they're generally well understood based on years of 6
experience.
7 We've had some discussion here earlier about possible j
8 changes undergoing in the understanding of these degradation
{
9 mechanisms.
The quote that came quite often was the jury is 10 still out on thesa mechanisms.
We're continually understanding
[
11 the relationship between the environment and the materials and 12 these interactions will continue to develop.
These 13 understandings will continue to develop as we go along.
This i
14 has been a factor of the operating plants and there's no reason 15 to expect this to change at all just because we're going into a 16 plant license renewal.
17 However, the industry and Jim Chardes present the i
18
' concept of the industry reports, particularly in the reactor 19 pressure boundary area we are renewing the unique aspects of 20 degradation mechanisms and how they are tied in in the license 21 renewal area.
22 We've seen lists of degradation mechanisms.
You've 23 seen the list of degradation mechanisms that were listed for 24 the irs.
We feel that we should -- as part of our evaluation 25 we'll be looking at age related mechanisms and looking at the
l 68 r~.
1 significant mechanisms in the plant license renewal area.
(
2 Now, in addition to the industry work that's going l
3 on, that is, the industry reports, each plant will then l
t 4
demonstrate their applicability to the industry report on a 5
plant unique basis and that's a point that I think got a little 6
muddled a little while back that we will be looking at the irs.
7 The irs -- the industry reports -- are doing the best they can 8
to encompass on a generic basis the relationship between 9
degradation mechanisms and materials but it will be up to the 10 individual plants to show that the conclusions reached in the 11 industry reports are applicable, i
12 As an example of a degradation mechanism, let me just
\\-
13 touch on fatigue, because that's a primary one in this area and 14 I might be stepping into it here but fatigue is a mechanism 15 that's always been considered in plant design.
What has 16 changed has been the complexity of supporting analyses.
This l
17 complexity has increased with the development of codes.
The 18 original B-31-1 codes, for instance, had implicit within it an i
19 assumption that the plant would go from -- would go through a 20 full temperature cycle some 7,000 times.
With the introduction i
L 21 of ASME 3 we're now doing explicit calculations for design 1
22 cycles.
23 Generally speaking our system, at least the reactor
()
24 pressure boundary system, has been very resistant to fatigue 25 problems.
Where we've been explicitly designing for fatigue we l
l
i I
69 l
I have not found ~~ we have n3t had many problems develop in that j
' {u) 2 area.
3 MR. SKAO:
Can I ask a question on this?
I 4
MR. CHILD:
Sure.
5 MR. SKAO:
Since Class I is B-31-1 --
6 MR. CHILD:
Right, B-31-1, yes.
+
t 7
MR. SHAO:
B-31-1 power has fatigue in a general i
8 sense, okay, but they don't have a local discontinuity aren 9
with fatigue?
(
10 MR. CHILD:
That's right, that's right.
The --
l 11 MR. SHAO:
Then how do you really know that what is 12 the really fatigue at, let's say, the local discontinuity area?
\\-
13-MR. CHILD:
Well, the point I was making was that 14 fatigue was considered.
It wasn't considered to the degree it 15 is today.
36 MR. SHAO:
How do we know that for licensing for the 17 local continuity area there's no fatigue problem?
18 MR. CHILD:
Well, what we're going to have to do is 19 still understand the differences between these codes and make 20 sure that these differences are understood and accounted for.
21 There's nothing new here that wasn't brought up already.
22 MR. SHAO:
Yes, I know, but for 40 years people say, 23 well, maybe you don't have to do a detailed analysis, maybe i
i
)
24 it's okay.
Now, for another twenty years how do we know the 25 additional, the additional damage because you don't really, we 1
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,-n
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3 70 i
I
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1 don't really have a good detail analysis, how do we know this, 2
this local area is okay?
i i
3 MR. CHILD:
Well, let's consider my next slide then.
i 4
What are the options open to us in the area of fatigue?
I'm 5
not saying we're going to dismiss fatigue.
We still have to 6
consider fatigue, but let's look at the options that may be i
7 open to us.
8 First of all, if you are a plant that's done a 9
detailed Section 3 analysis, you c&n re-do your analyses to 10 include the additional cycles that you will see for the renewal 11 period.
f 12 MR. SHAO:
That's the easy one.
13 MR. CHILD:
That's the easy one.
14 Now, if-you're a plant that does not have a current 15 design, let's say, current design basis under Section 3, there 16 are some options open to you.
One is to demonstrate a 17 similarity with a plant that has done Section 3 plants -- has 18 done a Section 3 analysis.
If you can show similar geometry I
l 19 and similar loading then you can reference to this Section 3 20 analysis and determine where they have found areas of high 21 fatigue usage.
22 MR."SHAO:
Their temperature had to be the same?
23 MR. CHILD:
That's right, that's right, because your 24 cycles and your geometry would have to -- you would have to l.
25 show a similarity in loading and as well as geometry and if so i
L
71
]
}.
I then you can use the trends that their analysis has shown to s/
2 demonstrate where you're going to get high fatigue usage and 3
when you know these areas you can then do the detailed 4
analyses.
5 The point I'm making is that there need not be an l.
6 exhaustive Section 3 analysis.
You can by benefit of history, f
I 7
by considering areas of geometry differences, you might want to 8
look at those particular areas and do a detailed analysis.
9 There are other areas where you can economize.
We 10 talked about using the actuhl plant transients to better 11 quantify the frequency of evenes.
12 MR. SHAO:
Detailed e.nalysis or not?
t 13 MR. CHILD:
You would only need to do the detailed 14 analysis for those areas where you have had high fatigue usage, 15 where you by one way or another feel that there will be high 16 fatigue usage and there's another area that's being looked at 17' now and is being discussed under Section 11 through the various 18 ASME code committees, and that's to look at a crack growth 19 potential.
I 20 MR. SHAO:
Okay, has anybody done an analysis dealing 21 with sharpening your pencil and you have to change your l
22 operating procedure?
23 MR. CHILD:
You're asking me is there any place?
, ()
24 MR. SHAO:
Yes.
25 MR. CHILD:
Where they have sharpened the pencil?
i i
72
()
1 NR. SHAO!
Sharpen the pencil -- you have to change 2
your operating procedure or --
l 3
MR. CHILD:
I'd guess I'd have to defer to someone 4
like Art Dearduff.
i 5
MR. DEARDUFFt Art Dearduf f.
Inherently there have l
6 been quite a few of these things that have gone on where cracks.
7 have been found in plants and so inherently that means that its-8 usage is greater than one and analyses have in many cases have 9
shown inclement life, no cracks.
[
10 MR SHAO:
Yes, but this is after the fact.
11 MR. DEARDUFF:
It's after the fact but it's --
l 12 MR. SHAO:
If many years ago they found cracks, and O
i l
13 the changed the design, but if you had found anything before 14 the cracks, you found it, you do a good analysis, you do a 15 detailed analysis and you found that the damage --
16 MR. CHILD:
May I try to re-phrase the question?
17 MR. SHAO:
Yes.
18 MR. CHILD:
Has designed -- has a fatigue analysis 19 aver influenced the design?
20 MR. DEARDUFF:
I'm certain it has.
You know, the
]
l 21 MSSS vendors have been doing fatigue analysis, well, let's say, 22 even before that when they were designing --
t 23 MR. SHAO:
I'm thinking for operating plants.
For 24 plants who are designed for B-31-1, if somebody re-do that 25 analysis using Section 3 and find out that fatigue damage is
i j
73 j
1 too high.
2 MR. CHILD:
Has there been an instance where someone 3
has done 3-31-1 and had to do, I mean, re-do?
l 4
MR. DEARDUFF:
Yes.
5 MR. SRAO:
Right.
l 6
MR. DEARDUFF People had to re-do fatigue 7
calculations on the surge line using Section 3 techniques and j
8 that influenced some designs in some plants, so the answer is 9
yes, after the fatigue was found --
t 10 MR. CHILD:
Until plant life renewal came along those 11 plants then had a basis in B-31-1, had no reason to re-do it 12 through Section 3 except to solve particular problems.
13 MR. SHAO:
B-31-1 never found a surge line --
14 MR. DEARDUFF:
Neither did Section 3.
15 MR. SHAO:
If you do it right.
16 MR. CHILD:
Do you wish to discuss this more?
l 17 MR. BLOCH:
Go ahead.
18 MR. CHILD:
I did bring up the crack growth potential
[
19 in which you consider the possibility of a crack just below the 20 level of detection and you determine the time it would take for 21 that crack to propagate.
Now, you can couple that with your 22 surveillance program as necessary, or if necessary.
You may 23 find that the crack will not propagate, that it would relieve 7-s l (_)
24 itself and that's an alternative method to doing a fatiguo type l
25 analysis, or to do an analysis to show the effects of fatigue.
i t
l i
74 I
()
1 Then finally, as an add-on, as another possibility f
2 which wouldn't replace, but would be in addition to these
)
3 methods above, there are various fatigue monitoring systems 4
being looked at now.
The point that I wish to make here is l
S that there are several methods available for managing an age-6 related degradation.
7 The methods can be summarized as: further analysis to l
8 demonstrate that the projection degradation is acceptable f
9 through the renewal period, or demonstrating the current 10 programs are adequate to assure the degradation mechanism does 11 not impact safety.
For the renewal period, you may want to go 12 to some procedural enhancement, and that's where the question
%)
13 of trending is a possibility as a means of assessing the 14 effecte of a degradation mechanism.
15 You can modify operating practices and in may cases, 16 you can consider component replacement or refurbishment.
In 17 managing degradation mechanisms, programs shou'.d only be 18 required for components important to safety.
That's not an 19 issue here when we're talking about resctor pressure boundary, 20 but in a general sense, as a message that Yankee wants to make 21 in this workshop, is that we should only be required to 22 institute programs for components important to safety.
23 No additional programs should be required for those 24 components that are already covered by existing programs, and 25 finally, any rule that's set up, should allow a flexibility for
I m
75 l
i i
1 managing. degradation.
t
)
2 MR. BLOCH:
Does it follow that a program is adequate f
3
'for the first forty years, continues to be adequate after that?
4 MR. CHILD:
Does it follow that a program adequate --
5 MR. BLOCH:
We have a program that is now in
{
6 existence that is adequate for the first forty years, but 7
questionable beyond that?
l 8
MR. CHILD:
Well, you make a demonstration that the 9
components -- that the existing programs are satisfactory for 10 the remaining -- for the license renewal period.
If the
)
11 existing program -- maybe I've gotten cause and effect a littlo r~m 12 mixed up here, but if the existing program is satisfactory, k.s 13 there's no need to impose additional programs.
Let me express 14 it that way.
15 So, additional administrative controls are only 16 applicable to special actions necessary to manage age-related 17 degradation in support of licensing renewal and then such 18 action should become license commitments for the license 19 renewal.
That concludes my presentation.
Yes?
20 MR. MANOLY:
The scope of the program we're talking j
21 about on safety; I don't think that's consistent with the 22 NUMARC documents.
The NUMARC document does not say --
l 23 MR. SHAO:
Safety related.
r 24 MR. MANOLY:
No, it doesn't say that.
There is a 25 distinction between new position and the NUMARC position on the
76 r
1 screening.
l
-~)
.%-)
i 2
MR. CHILD:
Well, I really don't want to get into a j
3 discussion of screening here.
It's not really applicable.
5 4
screening is not really applicable when you talk about the 5
reactor pressure boundary.
That was my point from the start.-
l l
We have plans for those check valves 7
that form part of the pressure boundary itself.
That is, that i
8 section that isolates inside the pressure boundary from outside j
i 9
the pressure boundary.
t 10 I'E talking not about the quality now specifically to 11 this and the other moveable parts that form a part of that j
12 boundary.
13 MR. CHILD:
Well, I think what we would have to do 14 is, we would have to -- that's getting into the question of 15 operability and integrity of the valves.
We would expect to 16 undergo a program to review our current valve inspection 17 techniques and periods of inspection and see if that's adequate i
18
'or if that can continue for the remainder of life.
Joe?
i 19 MR. McCUMBER:
This is Joe McCumber again from 20 Yankee.
In general, a lot of this discussion came up in the fluids one this morning.
We look at any fluid system as having 21 22 a couple of f' unctions; one being the pressure boundary and the 23 other being operability.
The operability function, from what
()
24 we've seen so far, the programs in place are doing a pretty 25 good job, we feel, in detecting or managing aging.
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1 The-concerns, the concerns with pins and disk's and f
2 all of that have.been identified attd there are several programs to disassemble and inspect as required.
So, we're hoping, e+
3 L
4 least from what we've seen right now, we think that that would 5:
- be the case.
There 'aay be augmentations or enhancements 5
required, but, you know,'we will look at them individually.
7 9.R. MARSH:
Do I hear you saying that you're going to 8
be systematically looking at programs that you have that are-
' I 9
required and make sure that they are disassembly programs and
. 30 comparability programs; that they are adequate?
11 MR. CHILD:
Yes.
- 12 MR. MARSH:
You mean systematically go through all of D()
13 those programs?
14 '-
MR. CHILD:
That's right.
15-MR. BURKE:
Rich Burke, EPRI.
The-IR -- and I could 16 be wrong here -- on TRAC being tentative.
I believe this is on 17, the pressure boundary, and someone tell me if I'm wrong --
18 someone from General Electric or from Westinghouse or from B&W.
19 However, the programs that answered this yesterday, in other 20 worde, the operability function would be part of the 21 methodology to evaluate plant equipment for license renewal for 22 all
- hose affected programs.
23 Those types of things, where all these other 24 committees are now involved with now looking at the 25 operability.
There are so many problems going on, we decided
78
)
1<
not to address those within these -- these are pressure i
2 boundary reports, looking at the integrity of that pressure L
3-boundary.
o e
4 Those programs would be considered effective if 5
implemented as part of this methodology doctrine.
6 MR. MARSH:
These valves-are not just your normal 7
operability valves.
These are pressure boundary valves.
8 You've got to be sure that you cover these check valves and 9
- MOVs, 10-MR. BURKE Pressure boundary integrity is 11-specifically being looked at,_PIVs, light water reactors, i
~
.12 pressurized water reactor.
The reactor cooling system.
It l
\\_s/
13<
does not look at a scope timed to 35 seconds of an MSIB or-the 14 spring packs, and so forth.
It doesn't look at things like 15 that in this particular industry report.
1.
l 16 Those types of things that you're addressing would be l
17 part of the methodology for license-renewal, to look at the 1:
18 functions independently, but not as part of this report.
The 19 answer is that it's just not part of the scope.
20 MR. MARSH:
Okay.
,L,
- 21 I've got an itch that hasn't been scratched yet.
22 PIVs have been a problem within the industry, not necessarily 23 for BWRs, but for PWRs.
We've seen numerous cases where N >Y
(
24-they've not been functional, and there ended up being leaks to 25 the outside of the containment.
What program is going to 1
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-MR. BURKE:
What particular program are we working 3
on?
4 MR. MARSH:
Be as specific as you can.
Tell me how
'5 you're going to make sure that the PIVs of the primary pressure I
6 boundary are going to stay adequate for the extended life.
7.
MR. BURKE:
The PIVs specifically --
8 MR. MARSH:
Those are the valves that I'm talking 9
about:
the pressure valves and the isolation valves.
10 MR. McCUMBER:
Again, Joe McCumber from Yankee 11 Atomic.
12 We look at any pressure boundary valve in two ways.-
D-13 The pressure boundary will be looked at based on the material 14 construction, and the environments that it's within.
The level 15 at which we will look at it will depend on now harsh those two 16 things combine.
If there is a concern, we will look at it l
l 17 closer.
18 The operability, again, we look at the package of
- 19 programs that are looking at that function right now and make 20 sure that valve does what it needs to do.
Right now, there 21.
seems to be significant program coverage on the safety 22 injection valves, looking at the types of things you've brought 23 up, as far as leakage and the valve discs.
They've been issues 24 that have been identified over the last 10, 20 years.
I think 25 we are covering them.
I think they may get more coverage than
~
Oh 80 1
some other valves, depending on the service conditions, the 2
environmental conditions.
3 MR. CHILD:
I'm getting the suspicion that what 4
you're saying is that the current testing method for these 5
valves are not adequate in today's -- I mean, it's not a PLEX 6
issue; it's an operating issue that you're raising.
7 MR. MARSH:
It may be partly that, but I don't want 8-to say it's'only a current possibility issue, because I think 9
for the extended life we have to make sure that the degradation i
10 mechanisms won't appear later on.
11 MR. McCUMBER:
Did I get closer to an answer?
12 MR. MARSH:
Yes.
You were closer that' time.
13-You've got a program where you systematically do the 14' simple check valves, and sometimes routine is bad.
15' MR. McCUMBER:. Well, I think in general that's not 1
L 16 done-today.
For the important valves, it is beginning to l
17 happen today.
There are valves that are being disassembled.
l l3 18
'Many plants have instituted programs that look at critical l-19 valves based on their safety importance and their environmental l
20 condition, and disassembling them, looking for the problem.
21 MR. MARSH:
Is that going to be a plant-specific 22 issue, or is this an industry issue?
23 MR. CHILD:
Well, I would think it would be -- if
()
24 it's indeed an industry issue, it should be looked at on an 25 industry basis.
~
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I e' s.
81 b[
-l' MR. MARSH:
Well,_it is an industry issue.
~\\ -
J s
2-MR. BURKE:
The answer is yes.
3 We at EPRI put each of those concerns in and 4
identified the industry concerns.
You can find the answer to It is a v. ry expensive check valve 5
your question right here.
e 6
text program.
It includes long-term deteriorations, if there
.7 are any.
8 We could spend a lot of time on thic, but-I'm not i
9 _.
sure it's appropriate.
1 10 MR. MARSH:
I think I've got enough to chew on.
11 Thanks a' lot.
,-sq 12 MR. RICHARDSON:
Anything else?
(
l 13 (No response.)
14 MR. RICHARDSON:
Our third and last speaker who has 15 requested some time for presentation is Edgar Landerman.
16 MR. LANDERMAN:
I think I've made my point.
17 MR. RICHARDSON:
You've made your point?
'1'8 '
MR. IANDERMAN:
Yes.
l-l 19 MR. RICHARDSON:
That, then, brings to an end those-L 20 that have asked for time.
I guess we will open it up for 1
21 anybody else that would like to make comments in this 22 particular area, that is, primary pressure boundary.
1 i
23 VOICE:
I'd just like to comment on Mr. Child's 24 presentation.
I thought it was very excellent.
I'm 25 particularly to hear again that not only are we considering i
.. - ~ _.., _ _ _.
82 1
license renewal, but I'think some of us -- or at least I did --
}/'ya -
'uf.
2 got the wrong impression.today that what is happening during-i
-3 the 40 years doesn't really.make that much difference.
It
-4 really does.
The operation, the maintenance, the inspection, 5
the testing, the monitoring of all those. things, are in license 6
renewal.
I think he made that very clear.
That also-includes 7
the record-keeping, certification of the documentation.
I B
think all of those things are very important, and I was glad to 9
hear him speak up.
10 MR. RICHARDSON:
Good.
Any other comments?
l.
11 MR. ZIGLER:
I'm Gil Zigler.
I'm with the ASME 12 subcommittee on vibration monitoring.
We've been working on L h ll d 13 the' vibration monitoring program for the primary ~ site of PWRs L
and BWRs since 1976.
One of the basic problems that we've been 14 15 having -- and we would like just to make this point one more l
l 16 time -- is this question of operating industry records, 17 training information, and documentation, which have not been 18
' maintained by operators, vis-a-vis one that has a very good, 19 close -- whatever that may be -- monitoring program.
It's an 20-issue that we have been trying to tackle within our L
21 subcommittee, and we find it an interesting point to debate.
22 I would hasten to add quickly that the NRC should 23 carefully look at this question about the differentiation 24 between a plant that has a known, proven track record, vis-a-l 25 vis a plant that does not have a known, proven track record.
~ -.
- \\
83 n
' /^',
l' We:have several' analogies.
In our subcommittee, we have been.
k.-
2 usingLthe analogy of the aircraft.
'3-MR. RICHARDSON:
Thank you.
4 Any others?
5 (No-response.)
6 MR. RICHARDSON:
If not, I want to say -- and I'm 4
7 sure I speak for Larry -- we appreciate your participation and 8
comments.
I understand that there will be some written 9
comments submitted.- We appreciate those.
That ends this 10 session, and the workshop will reconvene tomorrow morning-at h
111 8:30.
It~will be three sessions going on, so consult your q
t 12.
program.
13 Thank you very much.
14
[Whereupon, at 4:05 p.m., session 2 was concluded.]-
15 16 17-
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23
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25
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REPORTER'S CBRTIFICATE.
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Thia.is to certify that the attached proceed-ings before.the United-States Nuclear Regulatory Commission'
- in the-matter of:
NAME OF' PROCEEDING:
Session 2.Public-Workshop _
DOCKET NUMBER:
PLACE 0F PROCEEDING:
Reston, VA 4
were held as.herein appears, and that this is the-origina11 transcript thereof for the file of-the United-States Nuclear Regulatory Commission taken.by me and thereafter' reduced to typewrit.ing by me or under the direction,of the court report-ing company, and that the transcript is a true and' accurate record of the foregoing proceedinas, jm
(
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_trA_/I AA MARK HANDY Official Reporter Ann Riley & Associates, Ltd.
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NRC' WORKSHOP LON LICENSELRENEWAL-l NOVEMBER 13-14,1989.
l SESSION 2
- i l
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PRESENTATION ON REACTOR PRESSURE BOUNDARY i
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CEDRIC. L... CHILD YANKEE ATOMIC ELECTR OMPANY 9
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DEGRADATION MECHANISMS
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i i
. IDENTIFIED AND GENERALLY WELL UNDERSTOOD-BASED ON-YEARS OF EXPERIENCE
- UNDERSTANDING OF ENVIRONMENTAL / MATERIALS l
INTERACTIONS CONTINUE TO DEVELOP i
- INDUSTRY REVIEWING UNIQUE ASPECTS OF-j DEGRADATION MECHANISMS IN THE LICENSING l
RENEWAL ARENA l
- EACH UTILITY WILL DEMONSTRATE APPLICABILITY l
TO INDUSTRY STUDIES ON A PLANT UNIQUE BASIS I
t l
o o
o s
FATIGUE i
l
- HAS ALWAYS BEEN CONSIDERED lN PLANT DESIGN l
COMPLEXITY OF SUPPORTING ANALYSES l
INCREASED WITH DEVELOPMENT OF CODES l
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- SYSTEM DESIGN GENERALLY RESISTANT TO FATIGUE PROBLEMS l
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- REANALYSIS TO INCLUDE THE ADDITIONAL LICENSE RENEWAL PERIOD
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- SHOW SIMILARITY TO PLANTS WITH SEC lli ANALYSIS TO DETERMINE REGIONS OF HIGH USAGE.
DO DETAILED ANALYSES OF THESE REGIONS i
- USE ACTUAL PLANT TRANSIENTS TO BETTER QUANTIFY THE FREQUENCY. OF EVENTS l
- DETERMINE CRACK GROWTH POTENTIAL:AND
}
AUGMENT THE PLANT SURVEILLANCE PROGRAM AS NECESSARY
- CONSIDER FATIGUE MONITORING SYSTEMS 1
O O
O J
l l
MANAGING: DEGRADATION MECHANISMS 8
l l
- PROGRAMS SHOULD ONLY BE REQUIRED. FOR i
COMPONENTS IMPORTANT TO SAFETY l
- NO ADDITIONAL PROGRAMS SHOULD?BE REQUIRED l
FOR THOSE COMPONENTS ALREADY COVERED BY-EXISTING PROGRAMS l
i
- RULE SHOULD ALLOWL FLEXIBILITY-FOR MANAGING DEGRADATION l
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SEVERAL METHODS AVAILABLE FOR MANAGING DEGRADATION l
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- FURTHER ANALYSIS TO DEMONSTRATE l
THAT THE PROJECTED DEGRADATION IS l
ACCEPTABLE THROUGH THE RENEWAL PERIOD i
l
- CURRENT PROGRAMS ARE ADEQUATE TO l
ASSURE DEGRADATION MECHANISM DOES 1
NOT IMPACT SAFETY l
- FOR THE RENEWAL PERIOD, PROCEDURAL I
ENHANCEMENT MAY BE NECESSARY l
- e.g., Trending i
L l
- MODIFICATIONS TO OPERATING PRACTICES
- COMPONENT REPLACEMENT OR REFURBISHMENT.
O O-O i
ADDITIONAL ^ ADMINISTRATIVE CONTROLS l
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- ONLY APPLICABLE TO SPECIAL ACTIONS l
NECESSARY TO MANAGE AGE?RELATED
- i DEGRADATION IN SUPPORT OF LICENSE RENEWAL-i
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