ML20031D829
| ML20031D829 | |
| Person / Time | |
|---|---|
| Issue date: | 02/11/1977 |
| From: | Meyer R Office of Nuclear Reactor Regulation |
| To: | Kato W AMERICAN NUCLEAR SOCIETY |
| Shared Package | |
| ML20031D800 | List: |
| References | |
| FOIA-81-236 NUDOCS 8110140267 | |
| Download: ML20031D829 (8) | |
Text
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- r 'J e-FEB 1.1977
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Dr. Walter T. Kato Anerican Nuclear Society
_.244 East Ogden Avenue
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Hinsdale, Illinnis 60521 Dear Dr. Katoi Enclosed is a sim:nnry of the paper we were invited to submit for the MSTD session in June 1977 on neutoon absorber caterials.
The title of the paper is " Control Material Behavior in Com::mrcial.
Reactors," by R.O. Meyer, M.D. Houston, M. Tokar and F.E. Panisko.
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Sincerely,...
Ralph O. Meyer, Leader Reactor Fuels Section Core Performance Branch Division of Systens Safety Office of Nuclear Reactor Regulation a
Enclosure:
As stated cc:
D.E. Thomas, Westinghouse R&D
, Distribution: Central Files NRR Reading File D.E. Mahagin, Westinghouse TTanford
.CPB Reading File bec:
R. Heineman D. Houston..
F. Coffman M. Tokar.
R. Lobel F. Panisko (PNL).
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RMeyer PCheck Dross 1/23/77 1/ /77 1/ /77.
n9110140267 810906
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SUMMARY
COVER SHEET
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CONTRIBUTED PAPER INVITED PAPER FOUR COPIES REQUIRED
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c Control Material Behavior in Comercial Reactors TITLE.
AUTHOkW): (Ust autrots in the proper order and exactly as they are to be published. PLACE AN ASTERISK AFTER EACH AUTHOR WHO IS AN ANS MEMBER; AN "S" AFTER STUDENT AUTHOR.)
1.
R.O. Meyer
- 2.
M.D. Houston
- 3. fjr Tokap 4,.
F.E. Pantsko AFFILIATION (S):(Ust corresponding author's affiliation and complete mailing address.)
U.S. Nuclear Regulatory Comission, Washington, D.C.
20555 1.
2.
Sue 3.
Same
~4.
Battelle, Pacific Northwest Lab, Battelle Blvd.,
Indicate number of author to whom correspb8bblygpggty 99352. and complete page 4 1.
To whom should the page charge be billed? If,,S. Nuclear Regulatory Cor:nission Attach purchase order with appropriate purchase order number to original copy of the summary.
FOR CONTRIBUTED
SUMMARY
Identify ANS Division or Technical Group having cognizance of your subject In which subject catagory (from page 3) do you feel this summary belongs?
Altemative Category:
Has the substance of this summary been presented or published previously (including U. S. ERDA or equivalent reports)?
YES NO Give details Has the paper been submitted for publication in a technicaljournal?
YES NO Give details llave you presented related papers?
YES NO Give details If as this summary been approved for publication by your institution or company?
YES NO Give details FOR INVITED
SUMMARY
Which ANS Division or Technical Group invitedyou?
Materials Science and Technology Dr. J.L. Scott session No.
Person who invited you FOR CONTRIBUTED OR INVITED
SUMMARY
3 2
Number of: Pages Table <
Figures 300 Word Count: Text 385 + (No.of figures pias tables) x 150
+ (No. orlines or equationi x io) 685 Total Originalline drawings cir glossy black and white prints of es :h figure or table must be attached to original.
A COMPLETED
SUMMARY
COVER SHEET. TOGE1HER WITH Tile INFORMATION REQUESTED ON PAGE 4, MUST BE ATTACliED TO EACH OF, TliE FOUR COPIES OF TiiE
SUMMARY
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FILING AND MAILING INFORMATION LOG =
Name and mailing address of author to whom correspondence should be addressed.
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Telephone:
Commercial:
FTS:
492 7603 Contro1' Material Bei,avior in Comercial Reactors Title of Summary This is to acknowledge receipt of your summary.Please use the log number above in future correspondence.
This summary will be considered for inclusion in the program of the American Nuclear Society's 1977 Annual Meeting, New Yort. NY. June 12 17, 1977. Another copy of this form will be sent to you about February 25,1977 informing you of the Program Committee action.
Your paper has been reviewed and:
- l. Accepted for presentation at the 1977
- 3. It is suggested that your summary be Annual Meeting. (See Attached Instruc-corr.bined with the summary seferenced tions) as leg #
-(See Attachment) 2.It is suggested that your summary be
- 4. Rejected.(See At' ached Comments) revised.(See Attachment)
In all correspondence regarding your summary, please refer to the Log Number shown above.
Thank you for submitting this summary.
Sincerely, W. Y. Kato ANS Technical Program Chairman 1977 AnnualMeeting a
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,C0h7ROL MATERIAL BERAVIOR IN COMMERCIAL REACTORS by
.s R.O. Meyer, M.D. Houston, M. Tokar (NRC), and F.E. Panisko (BhW)
.The behavior of materials in control rods and burnable poison rods has taken on new interest in light of a recent experience'1n the St. Lucie 1 pressurized water reactor. During startup testing in that reactor, a power anomaly was observed'that was ultimately determined to be the result of a loss of poison (B C) through perforations (failures) in the poison-4 rod cladding.(1) The failures were unexpected because the cladding technology was the same as employed for the fuel, which presents a greater challenge to the cladding. For example, the poison pellets generate no significant heat, and they consist mostly of an inert ceramic A1 0, whose 23 characteristics are'w' ell known. The fact that low density A1023 has a fuel was not fully appreciated, however, greater affinity for water than UO2 and excess moisture was introduced during fabrication. This resulted in numerous failurt.s by cladding hydriding.
This paper reviews the materials properties and performance record' of poison materials in commercial reactors. Table I lists properties of com:non control materials.
The melting points of these materials are not approached in normal operation. The possibility of slumping and the fragility of borosilicate glass, however, pose special problems. 11elium I
10 generation and release is significant in poisons utilizing B and must be accommodated by an adequate plenum. Radiation-induced swelling is signifi-cant in most of the materials and must also be accommodated in design.
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' While all poiso'n materials are reasonably compatible with their cladding, A10 -B C readily absorbs moisture, which can lead to Zircaloy hydriding 23 4 in the absence of adequate controls.
Following perforation of the cladding, exposure of irradiated Al 0 -B C to hot water (coolant) can letd to 23 4 substantial loss of boron carbide by leaching.
Table II lists the types of solid poisons used by each U.S. fuel manufacturer.
The urania-gadolinia burnable poison ( ) used in BWRs is unique inasmuch as the gadolinium is incorporated in the UO2 fuel itself.
More than 40,000 urania-gadolinia rods have been irradiated in BWRs, and their failure experience has been slightly better than for regular UO2 rods (gadolinia rods operate at somewhat reduced powers).
The industry has accumulated experience with control materials over extended periods i
of time without materials dif ficulties, and some rod assemblies have operated as long as 17 years. With exception of the single A1 0 -B C 23 4 rod problem mentioned above, no significant control material difficulty ha's been reported, although minor mecha. < cal design problems have been experienced.
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Rafarsncan 1.
" Report to Congress on Abnormal Occurrences," NRC report, NUREG-0090-5, to be published.
2.
G.A. Potts, "Urania-Gadolinia Nuclear Fuel--Physical and Irradiation Characteristics and Materials Properties,"
General Electric report, NEDD-20943, to be published.
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7 Table I.
Properties of Control Materials 1
Material Approx.
Approx.
Approx. EOL Coolant Moisture
, Structural Melting EOL Cas (lle)
Swelling Compatibility Arrinity Integrity 1
(Sortening)
Release (%)
Behavior j
Temp. (*C)
(%AD/D) 4 s,
BgC 2450 10-15 at 2
Bulk reaction Surface Macrocracks 600 'F up to approx.
oxide forms in bulk 20 mils / month hydrate samples BgC-A1 023 2030 5
2-3 Rapid leaching Adsorbs 110 Stability 2
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(m.p. A1 0 )
of BgC readily dependent 2 3 on fabrica-I tion Gd 0 -UO2 Proprietary None Proprietary Similar to Similar to Similar to 23 i
(GE)
(CE)
UO 00 UO 2
2 2
1 Borosilicate Slow leaching Potential Glass (800) 100 1.5 or B and Na low breakage I
(Pyrex 7740) and' -
slumping j
1 I
a Table II.
Control Materials in Commercial Reactors
[.
Vendor 7u11 Length Part Length Burnable
,l Control Rods
. Power-Shaping Rods Poison Rods Ag-In-Cd{a) rods Ag-In-Cd rods Boros111cate glass in 304ss tubes in 304ss tubes tubing in 30liss tubes (*)
Westinghouse Future: B C pellets g
and #d-In-Cd rods in.30813s tubes l
General Electric B C granules 2
2 3 pellets
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UO -Gd 0 q
in 304ss tubes in Zr-2 tubes I
Ag-In-Cd(a) rods and B,C pellets and A1203-B4Cpelgs b
Combustion B C pellets in Inconel-625 rods in Ir li tubes y
Engineering Inconel-625 tubes in Inconel-625 tubes Ag-In-Cd(a) rods Ag-In-Cd rods A10-BgGpelle}s 23 t
Baboock & Wilcox in 304ss tubes in 34ss tubes in Zr-4 tubes l
I Future: bgg pellets in 304ss tubes BWR: UO -Gd 0 2
2 3 pellets in Zr-2 tubes i
A12 3-B C 0
9 PWR:
Exxon (Reloads) pellets in Zr 14 tubes l
N BgC-graphite compacts B C-graphite Gulf Atomic (HTGR) in Incoloy-800 tubes y
Reserve: a,C-graphite compacts in free flowing spheres graphite (a) 80 w/o Ag, 15w/o in, 5 w/o Cd.
(b) Rods incorporated in fuel rod positions.
(c) Rods in removable spider assemblies.
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