ML16340A592
| ML16340A592 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 09/12/1979 |
| From: | Stolz J Office of Nuclear Reactor Regulation |
| To: | Morrissey J PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7910040650 | |
| Download: ML16340A592 (18) | |
Text
kl. Kreger M. L. Ernst R.
P.
Denise R. Hartfield LED IE (3)
Bcc:
J.
R.
Buhhanan T. B. Abernathy ACRS $16)
The above information should be submitted expeditioosly in order that we can continue our review of your application in a timely manner.
Sincerely, Original si8ned by 8M'F. Nolz, Chief.
Light l<ater Reactors Branch No.
1 Division of Project Management 0
, R. ~L'."." '<BfAlItSI".II,;,,,
RC PDRL
'. 2 197~
Local PDR NRR Reading LllR 81 'File D. B. Vassallo Docket Nos:
50-D. F.
Ross and 0-323 S.
A. Varga M. Williams J.
F. Stolz Mr. John C. Morrissey B.
C. Buckley Vice President 8 General Counsel E.
G. Hylton Pacific Gas 8 Electric Company R. J. Mattson 77 Beale Street S.
H. Hanauer San Francesco, California 94106 J ~
PE Knight R. L. Tedesco
Dear Mr. Morriss'ey:
R.
C.
DeYoung
.V. A. Moore
SUBJECT:
REQUEST FOR-ADDITIONAL INFORMATION IN REGARD TO DIABLO CANYON, UNITS 1 5 2 As a result of our review of your submittal entitled "Specification for Seismic Review 'of Major Structures for 7.5 Hosgri Earthquake,"
dated February 2, 1977, revised February 8, 1977, we find that additional infor-
- mation, as described in the enclosure, is required in order to-continue our review.
Jl Me have also reviewed information submitted by the llestinghouse Corporation on their experience with guide-thimble-tube and find that responses to the questions, as described in the.'enclosure on this matter, is required.
More-over, references 1, 3 and' of the enclosure should be indorporated into your Final Safety Analysis Report to the extent that they are applicable.
Enclosure:
Request for Additional Information CC:
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Nr. John C. Horrissey P.r.
John C. Morrissey Vice President 8 General Counsel Pacific Gas
& Electric Company 77 Beale Street San Francisco, California 94106 CC:
Philip A. Crane, Jr.,
Esq.
Pacific Gas
& Electric Company 77 Beale Street San Francisco, California 94106 Janice E. Kerr, Esq.
California Public Utilities Commission 350 NcAllister Street San Francisco, California 94102 Nr. Frederick Eissler, President Scenic Shoreli.ne Preservation Conference, Inc.
4623 More Mesa Drive Santa
- Barbara, California 93105 Hs. Elizabeth E. Apfelberg 1415 Cazadero San Luis Obispo, Cal.ifornia, 93401 Ns.
Sandra A. Silver 1760 Aljsal Street
- San Luis Obispo, California 93401 Nr. Gordon A. Silver 1760 Aljsal Street San Luis Obispo, California 93401 Paul C. Valentine, Esq.
321 Lytton Avenue Palo Alto, California 94302 Yale I. Jones, Esq.
19th Floor 100 Van Ness Avenue San Francisco, California 94102 Nr. Richard Hubbard HHB Technical Associates 1723 Hamilton Avenue Suite K
San Jose, California 95125 Hr. John Marrs Managing Editor San Luis Obispo County Telegram - Tribune 1321 Johnson Avenue P.
0.
Box 112 San Luis Obispo, California 93406 Elizabeth S.
- Bowers, Esq.,
Chairman Atomic Safety
& Licensing Board U.
S.
Nuclear Regulatory Commission Washington, D.
C.
20555 Hr. Glenn 0. Bright Atomic Safety
& Licensing Board U.
S. Nuclear Regulatory Commission Washingt'on, D.
C.
20555
~ 0 Tolbert Young P.
0.
Box 219 Avila Beach, California 93424 Richard S.
- Salzman, Esq.,
Chairman Atomic Safety
& Licensing Appeal Board U.
S.
Nuclear Regulatory Commission Washington, D.
C.
20555 Dr.
W.
Reed Johnson Atomic Safety
& Licensing Appeal Board U.
S. Nuclear Regulatory Commission Washington, D.
C.
20555 Alan S. Rosenthal, Esq.
Atomic Safety
& Licensing Appeal Board U. S. Nuclear Regulatory Commission Washington, D.
C.
20555 Ms.~Ra e Fleming 1920 Mattje~oad'ShellBeach. California 93440 Brent Rushforth, Esq.
Center for Law in the Public Interest 10203 Santa Honica Boulevard Los Angeles, California 90067 Arthur C. Gehr, Esq.
Snell 8 Wilmer 3100 Valley Center
- Phoenix, Arizona 85073
Hr. John C. Morrissey Mr. James
- 0. Schuyler, Nuclear Projects Engineer Pacific Gas 8 Electric Company 77 Beale Street San Francisco, California 94106 Bruce Norton, Esq:
3216 North 3rd Street
. Suite 202 Phoenix, Arizona 85012 Mr.
W.
C. Gangloff Westinghouse Electric Corporation P. 0.
Box 355 '
Pittsburgh, Pennsyl'vania 15230 Michael R. Klein, Esq.
Wilmer, Cutler 8 Pickering 1666:
K Street, N.
W.
Washington, D.
C.
20006 David F. Fleischaker, Esq.
'1919 Pennsylvania
- Avenue, N.
W.
Suite 501 Washington, 9.
C.
20006 Dr. William E. Hartin Senior Ecologist Battelle Memorial Institute
- Columbus, Ohio 43201 W: Andrew Baldwin, Esq.
124 Spear Street San Francisco, California 94105
0 PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON SITE NUCLEAR STATION UNITS 1
AND 2 DOCKET NOS.
50-275 AND 50-323 REQUEST FOR ADDITIONAL INFORMATION FUEL HANDLING BUILDING CRANE, POL'AR CRANE TURBINE BUILDING CRANE INTAKE STRUCTURE CRANE
'1.
The. Fuel Handling Building Crane and Polar Crane are located in the
'auxiliary building and the containment structure respectively.
Both of these structures are classified as Class I structures.
The structural acc'eptance criteria, allowable stresses etc.,
should be based on ihe codes and standards listed in the FSAR unless otherwise noted in the "Specifica-tion for Seismic Review of Major Structures for 7.5 Hosgri Earthquake" dated February 2,
1977, Revised February 8, 1977.
The Turbine Building Crane and the Intake Structure Crane are located in the turbine building and over the intake structure which are classified as Class II structure.
These cranes should be designed according to the appropriate criteria contained in the Specification provided for such structures.
Your descrip-tion of the structural criteria contained in Section'A,
- Cranes, indicates that all of these cranes have been re-evaluated according to one set of criteria regardless of their location.
The basic approach of the Specifica-
. tions "calls for the use of the same analysis procedures and criteria which were used and accepted at the time of the original DDE analysis..." the allowable stresses contained in Section 4A.4.3, Structural Evaluation are based on the elastic limit instead of working stress approach.
Additionally, it appears that the allowable stresses are those which are contained in the AISC Specifications, Part 2, plastic design, and applied to the methods of the AISE Specifications, Part 1, Elastic Design.
e
In view of the above, you are requested to discuss the rationale of your structural criteria for evaluation of the subject
- cranes, and justify the allowable stresses used and demonstrate that your approach meets the intend of.the Specifications,
~2.
The results of the total maximum stress ratios, app'ear to be obtained by means of the square-root-of-the-sum-of-the-squares (SRSS).
Indicate if the tabulated ratios (transverse, longitudinal and vertical) components have been obtained by means of SRSS or by direct.addition
'GUIDE THIMBLE TUBE WEAR 1..
Please provide the basis and derivation of the guide thimble wear model
'described in Reference l.
In particular, explain assumption 4 and the equations provided under assumption 7.
Does the model predict maximum
~ local wear or average circumferential wear?
1 2.
Using the guide thimble wear model, Westinghouse has predicted maximum stresses and stress intensity limits for worn guide thimble walls
>n two fuel assembly
- designs, which were subjected to a
6g handling load.
These calculated values are listed i n Table 4.1 of Reference 1.
Me note that the stress intensity limits increase as a function of time for both fuel assembly designs and that the limits always remain greater than the maximum stresses, which increase as the wall is worn away.
From
~
0 the supporting discussion preceeding Table 4.1, it is not clear sf the stress in.ensity limits are time dependent.
Such an assumption would explain the noted increase in stress limits, but does not address the decreasing material toughness. associated with irradiation hardening.
If such credit is being used, it is contrary to the previous Westinghouse position in Reference 2 and item 4.0.5 of Reference 1.
Please clarify whether or not Westinghouse has taken credit for irradiation strengthening.
'"" '" "" "-"Show that-the-criteria adopted represents. the. more conservative
- approach, 3.
Guide thimble wear data, which were taken from point Beach Units 1
and 2
spent fuel, are discussed,
- listed, and plotted in Section 2.3, Table 2.1, and Figure 5, respectively, of Reference 1.
Please confirm that the time units in Section 2.3 and Table 2.1 are in error and make correctinn.
as needed.
Should not the uni ts be days instead of hoursv 4.
Submitted'Westinghouse information does not explain why the guide thimble wear model, which was developed from measurements taken on two 2-loop plants with 1.4x14 fuel assemblies,.is applicab)e to wear predictions on
~ plants of other designs.
Other NSSS-vendor-designed plants have exper-ienced a "plant-specific" and "core-position" dependence in the observed wear.
Therefore, please explain how the model accounts for wear differ-ences'and provide supporting data for all Westinghouse design variations,-;
to the extent that they are applicable to Diablo Canyon, Units 1
8 2.
If the analytical treatment of design variations are justified, the sup-'orting data can be provided in a confirmatory manner after NRC approval of the model.
Please provide details of your data-gathering
- proposal, a
schedule for its implementation, and state your commitment to carry out this confirmatory program.
This data-gathering program should be completed
'expeditiously considering the availability of irradiated assemblies in all Westinghouse plants.
0
5.
In Reference 3, Nestinghouse stated that the effect of hydrogen content
'I on the mechanical properties of Zircaloy is discussed in WCAP-9179 (Re erence 4).
Me have reviewed that topical report and found no informa-
'--- - tion-on-this issue.
- Please provide your evaluation of how this considera-tion affects the safety analysis.
Include in this evaluation a description of the propensity for hydrogen uptake of the Zircaloy as a function of the accumulative we'ar.
6.
Mhen eddy current testing was conducted on worn guide thimble tubes from.
the. Point Beach Units, did the presence of zirconium hydrides affect the results~
How sensitive is the interpretation of eddy current signals to hydride presence'?
How is this effect taken into account'?
7.
References 1, 3, and 5 do not address the consequences of hole formation in worn guide thimble tubes.
Horeover, it is not clear from the submitted information if Mestinghouse (1) has observed holes during inspection of the 49 quide thimbles tubes that were examined in the Point Beach spent
\\
fuel, or (2) has predicted pith the guide thimble wear model ) hole formation to occur during projected fuel lifetime.
Please clarify.
Also, if holes have been observed or are anticipated, provide a discussion on the impact o,
such holes on guide thimble tube integrity, control rod motion, and thecal-hydraulic performance.
This discussion should also account for flow-in'duced vibration resulting in crack propagation and possibly fatigue fracture in locally thinned areas of the thimble wall.
This dis-cussion should address the integrity of the thimble tubes during the entire core residence time; both during periods of wear (under RCCA) and when the fuel assemblies are not under RCCAs.
0
C 8.
During the review of MCAP-9179 (Reference 6), the staff questioned the Xestinghouse value for the ultimate tensile strength of Zircaloy components.
The subsequent Mestinghouse response (Reference
- 2) stated that the ultimate d
""""'""""tensile"strength of-Zircaloy-was not used-.in the,.design.analyqes,of,present fuel assembly designs..
However, the analysis contained in Reference 1
uses the; ultimate strength as a limiting variable.
Therefore, please submit fot review the Mestinghouse correlation for the ultimate tensile strength of Zircaloy.
9.
Section 4.1 of Reference 1 states that the stress intensity factors are
.plotted as a function of time for 14xl4 and 17x17 fuel assemblies in Figure 5.
This does not appear to be correct.
Please provide such a figure or d
Figure 5 as necessary.
10.
Per item 4, Section 4.0 of Reference 1, your analyses are based on uniform wear in all thimble tubes.
Address the margin of conservatism for this assumption.
Compare your results with an analysis that considers non-
, uniform wear resulting in a shift of the neutral axis.
Note that such shifts will result in both direct stress and bending stresses.
ll.
For Condition-1 and -2 load analyses of Reference 1,
a skew factor is mentioned that accounts for the uneven axial load distribution.
Clarify how the skew factor is related to both geometric changes (resulting from uneven wear) and assembly misalignment.
How does the skew factor impact the load ana1yses?
12.
The equation for the wear volume in Reference 1 appears linear with time.
However, in Figures 5 and 6, wear depth is plotted versus time, and the resulting correlation appears to be non-linear.
Please provide information.
on how these parameters are related.
13.
For Condition-3 and -4 load analyses described in Reference nce 1 it is stated that the stresses in a worn guide thimble tube are based on generic stress calculations.
Please r eference where thes g
e eneric stress calcula-Z
- '"'pioncan-be-fpund-in.-the-. P&AR;-'t"-,'is. also-stated
-that-the -stresses-dn-
-the-unw'orn'-
guide thimble tubes are increased to account for the reduction of the tube cross section due to the wear scar.
Thss would
'ldindicate credit for a load redistribution to the unworn guide thimble tubes, Is a skew factor employed in the Condition-3 and -4 load analyses?
If not, )ustify its ommission.
Descri'be the state of stress in the worn guide tubes and how the uneven wear affects rthe load-bearing characteristics of the worn-tubes.
References
.1.
T.
M. Anderson (W) letter (NS-TMA-2102) to D.
G. Eisenhut (USNRC);
dated June. 27, 1979.
2.
T.
M. Anderson (W) letter (NS-TMA-1985) to J.
F. Stolz (USNRC),
dated November 10, 1978.
3.
T.
M. Anderson (W) letter (NS-TMA-1936) to D.
G. Eisenhut (USNRC),
da.ed September T2, 1978.
I 4.
P. J.
Kuchirka "Pro erties of Fuel and Core Com onent Materials,"
p P
Westinghouse Electric Corporation Report, WCAP-9179, Rev. 1, dated July 1978.
5.
T.
M. Anderson (W) le..er (NS-TMA-1992) to D.
G. Eisenhut (USNRC),
dated December 15, 1978.
~
P. J.
Kuchirka, "Properties of Fuel and Core Component Materials,"
Westinghouse Electric Corporation Report, WCAP-9179, dated October 25, 1977.
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