ML19210E472
| ML19210E472 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/23/1979 |
| From: | Reid R Office of Nuclear Reactor Regulation |
| To: | Arnold R METROPOLITAN EDISON CO. |
| References | |
| NUDOCS 7912050081 | |
| Download: ML19210E472 (7) | |
Text
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UNITED STATES
- 57.,'i NUCLEAR REGULATORY COMMISSION
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WASHINGTON. O. C. 20555
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November 23, 1979 Docket No. 50-289 Mr. R. C. Arnold Senior Vice President Metropolitan Edison Company 260 Cherry Hill Road Parsippany, New Jersey 07054
Dear Mr. Arnold:
Significant wear of the Zircaloy control rod pice tubes has been observed in facilities designed by Combustion Engineering (CE).
Similar wear has also been reported in those facilities designed by Westin@ouse (W).
In our letter of June 13,1978, we requested infomation from Babcek and Wilcox (B&W) on the susceptability of the facilities designed by B&W to guide tube wear.
The infomatind provided by B&W by letter dated January 12, 1979 was insufficient for us to conclude that guide tube wear was not a significant problem in the facilities designed by B&W. This was documented in our letter to B&W dated August 22, 1979.
Because significant guide tube wear could impede the control rod scram capability, and also effect the required coolable georetry of the reactor core, we consider this wear phenomenon a potential safety concern.
Therefore, we are requesting that you provide detailed infomation on the wear character-istics of the control rods on the guide tubes in fuel assemblies in Three Mile Island, Unit No. 1.
The enclosed NkC concerns are provided to assist you in planning your control rod and guide tube surveillance program. When you have completed your surveil-lance program pla,1, we request that this program be submitted for NRC review before implementation.
\\lthough this data-gathering program may be perfomed on available irradiated assemblies in spent fuel pools, we find that this issue should be resolved for each facility before startup from your next scheduled refueling outage commencing after January 1,1980.
To expedite our review of ycur program, a meeting at NRC headquarters in Bethesda, Maryland, has been scheduled for December 20, 1979, at 9:30 a.m.
This meeting will provid. you the opportunity to clarify and discuss the enclosed MRC concerns anc the details of your proposec progran.
Your acenda of the meeting should be crovided by December 17, 1979.
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. Should you have any questions on the type nf infomation we need or scheduling requirements, please contact our Operating Reactors Branch #4 Project Manager assigned to your facility.
Sincerely,
~
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n'., / -/' !) /.. Q 'i d RIbehtW.Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors Enclosure cc: w/ enclosure See next page 1500 329
Me ropolitan Edison Company e H. J rdan Oak Ridge, Tencessee 37830 ccw/enclssure(s).
Mr. Marvin I. Lewis Dr. Linda W. Little 6504 Bradford Terrace 5000 Hermitage Drive P, hila delphia, Pennsylvania' 19149 Raleigh, North Carolina 27612 Walter W. Cohen, Cons.mer Advocate Holly S. Keck Department of Justice Anti-Nuclear Group Representing Strawberry Square,14th Floor York Harrisburg, Pennsylvania 17127 245 W. Philadelphia Street York, Pennsylvania 17404 Robert (, Knupp Esq.
Assistant Solicitor John Levin, Esq.
Knupp and Andrews Pennsylvania Public Utilities Com.
P.O. Box P Box 3265 407 N. Front Street Harrisburg, Pennsylvania 17120 Harrisburg, Pennsylvania 17108 Jordan D. Cunningham, Esq.
John E. Minnich, Chairman Fox, Farr and Cunningham Dauphin Co. Board of Comissioners 2320 North 2nd Street Dauphin County Courthouse Harrisburg, Pennsylvania 17110 Front and Market Sts.
Harrisburg, Pennsylvania.17101 Theodore A. Adler, Esq.~
WID0FF REAGER SELK0WITZ & ADLER
- Atomic Safety and Licensing Appeal Board Post Office Box 1547 U.S. Nuclear Regulatory Commission Harrisburg. Pennsylvania 17105 Washington, D. C.
20555 Ms. Marjorie M. Aamodt Atomic Safety and Licensing Board Panel R.D. f5 U.S. Nuclear Regulatory Commission Coatesville, Pennsylvania 19320 Washington, D. C.
20555 Ms. Karen Sheldon Docketing and Service Section Sheldon, Harmon, Roisman & Weiss U.S. ?fuclear Regulatory Commission 1725 I Street, H. W.
Suite 506 Washington, D. C.
20555 Washington, D. C.
20006 Robert Q. Pollard I'
Earl B. Hoffman Chesapeak Energy Alliance
'609 Montpelier Street
, Dauphin County. Comissioner Baltimore, Maryland 21218 Dauphin County Courthouse Front and Market Streets Chauncey Kepford Judith H. Johnsrud Ellyn Weiss, Esq.
Environmental Coalition on Nuclear Power Sheldon Harmon, Roisman & Weiss
$e50 433 Orlando Avenue State College, Pennsylvania 16801 Washington, D.C.
20006 Ms. Frieda Berryhill, Chairman Mr. Steven C. Sholly Coalition for Nuclear Power Plant
~304 South Market Street Postponement 2610 Grendon Drive Mechanicsburg, Pennsylvania 17055 Wilmington, Delaware 19808 Mr. Thomas Gerusky Mrs. Rhoda D. Carr Bureau of Radiation Protection 1402 Marene Drive Department of Environmental Resources P.O. Box 2063 Harrisburg, Pennsylvania 17109 Harrisburg, Pennsylvania 17120 1500 T30
Karin W. Carter, Esq.
505 Executive House P. O. Box 2357 tietropolitan Edison Company Harrisburg, Pennsylvania 17120 Honorable Mark Cohen 512 E-3 Main Capital Building cc w/ enclosure (s):
G. F. Trowbridge, Esquire Dauphin County Of fice Emergency Shaw, Pittman, Potts & Trowbridge Preparedness 1800 M Street, N.W.
Court House, Room 7 Washington, D. C.
20036 Front & flarket Streets Harrisburg, Pennsylvania 17101
= - -
GPU Service Corporation Richard W. Heward, Project fianager Mr. E. G. Wallace Department of Environmental Resources Licensing tianager ATTN: Director, Of fice of Radiological 260 Cherry Hil1 Road Heal th Parsippany, New Jersey 07054 Post Office Box 2063 Harrisburg, Pennsylvania 17105 Pennsylvania Electric Conrany lir. R. W. Conrad Director. Technical Assessment Vice President, Generation Division 1001 Broad Street Office of Radiation Programs Johnstown, Pennsylvania 15907 (AW-459)
U. S. Environmental Protection Agency
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Miss Mary V. Southard, Chairman Crystal Mall #2 Citizens for a Safe Environment Arlington, Virginia 20460 Post Office Box 405 Harrisburg, Pennsylvania 17108 Mr. Roberc B. Borsum Babcock 's Wilcox Government Publications Section Nuclear Power Generation Division State of Library of Pennsylvania Suite 420, 7735 Old Georgetown Road Bcx 1601 (Education Building)
Bethesda, Maryland 20014 Harrisburg, Pennsylvania 17126
- Ivan W. Smith, Esq.
Mr. David D. Maxwell, Chairman Atomic Safety & Licensing Board Panel Board of Supervisors U.S. Nuclear Regulatory Commission Londonderry Township Washington, D. C.
20555 RFD#1 - Geyers Church Road fliddletown, Pennsylvania 17057 U. S. Environmental Protection Agency Region III Office ATTN:
EIS COORDINATOR Curtis Building (Sixth Floor)
Governor's Office of State Planning
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and Development 6th and Walnut Streets ATTN: Coordinator, Pennsylvania Philadelphia, Pennsylvania 19106 State Clearinghouse Mr. J. G. Herbein P. 0. Box 1323 Vice President Harrisburg, Pennsylvania 17120 Metropolitan Edison Comparty 1-P. O. Box 480 Middletown, Pennsylvania 17057 Ms. Jane Lee R.D. 3; Box 3521 Etters, Pennsylvania 17319 1500 331
Enclosure NRC CONCERNS ON CONTROL R00 GUIDE TUBE WEAR IN FACILITIES DESIGNED BY B&W The B&W surveillance experience on worn control rod guide tubes, as described in their January 12, 1979 letter, consists of (a) air testing of sixteen guide tubes from an Oconee-1 15x15 fuel assembly that had experienced one cycle c' operation under a control rod assembly and (b' clam-shell sectioning of two guide tubes from a 17x17 fuel assembly that had undergone a 1000-hour flow test under a control rod assembly. As documented in our letter of August 22, 1979, we find that this experience is not sufficient to support the B&W con-clusion that there is strong. evidence for the absence of wear'in B&W-designed plants.
In fact, to the contrary, worn guide tubes have been observed in Crystal River, Un;t 3 spent fuel (see BAW-1490 Rev.1, July 1978). Our position is further based on observations made by other NSSS vcndors who have found a " plant-specific" and " core-position" dependence'in the observed wear.
Furthermore, out-of pile flow tests have demonstrated that the wear rate is a function of several design and operating varicbles.
1.
Propose a post-irradiation examination (PIE) program with a scheduie for its implementation and a commitment to execute the program for NRC review.
This data-gathering program should be completed expeditiously considering the availability of irradiated assemblies in all B&W-designed plants.
Details of the surveillance plan should include the following:
a.
Methods o# examination (e.g., destru:tive, ecdy current crobe, boroscope, mecharical gage) accompanied by cualification of those methods, b.
Characterization of the examined guide tubes, including their in-core locations, EFDHs, flow rates, fluer.ce, and wear tire under rods (control, instrument, axial-power shaoing, burnable poison, startup source, ar d orifice).
c.
Examination C those rods (centrcl, ir.stru ett, axial-;ower shacing, burnable coison, startue scur:e, and orifice) contained within the guide tubes to identify #atigue, stress corrosion 8b"0@gg{
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2 cracking, wear, denting, or any other conditions that can degrade their design function, reduce their design lifetime, or impede their movement.
d.
Analysis of results including quantification of guide tube wall wear depth and distribution. This PIE program may be satisfied in part of totality by reference to data taken from another B&W designed plant (s) that uses the same type of fuel assemblies.
In such case, justification must be given that wear in the refere.nced plant adequately represents that of the plant design in question.
Provide all correlations supported by your tests and discuss how these correlarions are e.!d to predict guide tube wear during reactor operations over the fuel lifetime.
2.
Provide an evaluation on the predicted guide tube wear on the stress analyses contained in the FSAR. The evaluation should address loadings associated with Condition-1 through -4 events including fuel handling accidents, control rod scrams, aM seismic and LOLA transients. The discussion should describe the state of stress in the worn guide tubes and how the wear affects the loadbearing characteristics of the worn tubes.
(Note that nonuniform wear results in a shift of the neutral tube axis which then induces not only direct stresses but also bending stresses.) Show that the loadbearing capacity of the worn guide tubes satisfies the acceptance criteria for these loading events.
3.
Provide or reference all material property correlations that are used in the guide tube stress analyses.
These cerrelations should accommodate the effects of hydrogen absorption and the procensity for hydrogen uptake in the Zircaloy guide tubes as a function of accumulative wear.
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. 4.
Address the consequences of hole formation in worn guide tubes.
Consider the extent and distribution of wear to see if hole formation is possible.
If the potential for hole formation can-not be discounted, evaluate the impact of such holes on the guide tube integrity, control rod motior and local thermal-hydraulic perfo rmance. This evaluation should account for flow-induced vibration resulting in crack propagation and possible fatigue frac-ture in locally thinned areas of the tube wall. This discussion should also address the entire core residence time, both during periods of wear (under rods; i.e., control, instrument, axial-power shaping, burnable poison, startup source, and orifice) and when the tubes are not rodded.
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