ML20002E531
| ML20002E531 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/28/1971 |
| From: | Walke G, Wall H CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Morris P, Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8101280511 | |
| Download: ML20002E531 (8) | |
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Dr. P. A. Morris, Director Re: Docket 50-155 Division of Reactor Licensing DPR-6 ZEK United States Atomic Energy Proposed Tech Spec Commission Change 26 Washington, DC 205h5
Dear Dr. Morris:
Attention: Mr. D. J. Skovholt Transmitted herewith are three (3) executed and thirty-seven (37) conformed copies of a request for a change to the Tech-nical Specifications of License DPR-6, Docket No 50-155, issued to Consumers Power Company on May 1,1964 for the Big Rock Point Nuclear Plant.
This proposed change (No 261 rill enable Consumers Power Company to insert into the reactor at Big Rock Point a control rod blade design designated as " Type 2A."
These control rods are essen-tially identical to the " Type 2" control rods that are now in the core. The slight changes in design are required for improved manu-facturing techniques.
It is our intention to insert " Type 2A" control rods into the Big Rock Point Reactor during our next refueling outage which is currently scheduled for February 3971. We would, therefore, be most appreciative of an expeditious handling of this Request for a Techni-cal Specifications Change so that we might receive approval before March 1, 1971.
Yours very truly, C
Nuclear Fuel Management Administrator i
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CONSUMERS POWER COMPANY Docket No 50-155 Bequest for Change to the Technical Specifications Change No 26 License No DPR-6 For the reasons hereinafter set forth, the following changes to the Technical specifications of License DPR-6 issued to Consumers Power Company on May 1,1964 for the Big Rock Point Nuclear Plant are requestedt
.I.
Changes: Section 5 A.
Change Section 5 1.2 to read as follows:
"5 1.2 Control Reds Number of Control Rods:
Type 1 16 Type 2A 16 Poison Material - B C Powder in 304 SS g
Tubes or B C Powder in 304 ss Tubes g
and 304 ss Tubes Pitch (square Array), Inches 10.466
-Active Length, Inches 68 Shape Cruciform Width, Inches 11-1/2 Blade Thickness, Inches 5/16 Sheath Thickness, Inches Type 1
.062 Type 2A
.056 Number of B C Filled, 304 SS g
Tubes per Control Rod Type 1 116 Type 2A 64
- Number of Empty 304 ss Tubes per Control Rod Type 1 o
Type 2A 40
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2 304 SS Tube, B C Filled, Out er g
Diameter, Inches Type 1 0.175 Type 2A 0.188 304 SS Tube, B C Filled, Wall g
Thickness, Inches Type 1 0.020 Type 2A 0.025 3Oh SS Tube, Empty, Outer Diameter, Inches Type 1 None Type 2A 0.188 30h SS Tbbe, Empty, Wall Thickness, Inches Type 1 None Type 2A 0.025" II.
Discussion - Type 2A Control Rod Blades A.
Control Rod Blade Description The " Type 2A" control rod blades are of the same general design as the now existing " Type 2" control rod blades. Each wing of the cruciform-shaped blade contains a series of inner 304 SS tubes that are empty, and a series of outer 304 SS tubes filled with powdered B C.
g The entire row of tubes is then wrapped with a stainless steel sheath for increased structural rigidity.
During the manufacturing process of the " Type 2" control rod blades, all of the stainless steel absorber tubes were svaged down from an initial diameter of 0.188 inch to a final diameter of 0.175 inch.
Seventeen of these absorber rods, along with twelve empty rods, formed one wing of the cruciform blade.
In order to eliminate the large amount of cold-working in-volved during the svaging process, the " Type 2A" design utilizes non-svaged tubing with a diameter of 0.188 inch. To maintain the wall strength of the annealed 3Oh SS, the wall thickness has been increased from 0.020 to 0.025 inch. To maintain the ball spacers in place and thus ensure the B C powder is evenly distribited over the length of the tube, the g
tubing is slightly dimpled on either side of the ball spacer. This nonswaged design control rod blade is currently in use in all of General Electric Company's latest reactors.
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Because-of the increased tube diameter, the number of empty -
tubes has decreased from 12 to 10, and the number of poison tubes has de-
-creased from 17 to 16. The sheath thickness has also decreased slightly, l
from 0.062 to 0.056 inch.
B.
Nuclear Characteristics The " Type 2A" control rod blades are similar to the' present
" Type 2" blades in nuclear design.
In comparing two control rod blade designs,.two design para-meters that should be examined are boron content and effective blade area.
The boron content is related to desired blade life through boron depletion, i
and the effective blade area is related to control rod worth.
The " Type 2A" blades have approximately 2% less boron than j
the " Type 2" blades. This very slight decrease in baron content should l
have no appreciable effect on blade life.
Since boron is a very effective thermal neutron absorber, most absorptions take place near the surface of the control rod blade. As the effective surface area of the blade increases, the absorbing region in-creases and the rod worth goes up accordingly. There is approximately 1%~
more blade area in the " Type 2A" design than in the " Type 2" design. This increase stems from the slightly larger span of 16 rods with a 0.188-inch diameter over 17 rods with a 0.175-inch diameter. The slight difference l
in effective blade area vill not significantly affect the control rod worth.
As neither control rod worth nor boron lifetime has changed in the " Type 2A" design over the " Type 2" design, the "iype 2A" control rods present no difference over the present " Type 2" control rods with respect to nuclear characteristics.
C.
Quality Assurance Program Quality assurance requirements were carried out as a part of QA activities involving fuel and other reactor components manufactured by General Electric for Consumers Power Company. Our QA program involves planned audits of the design and manufacturing stage of fuel or c"uponent i
production with all auditing based on the eighteen (18) criteria of 10 l
CFR 50, Appendix B.
Vendors supplying components to the control rod blade assem-blies were reviewed. The manufacturing process and quality control inspection i
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Is points were reviewed and found satisfactory. A document search was ini-tiated on control rod blade subcomponents and documentation was found to be in order. A visual inspection of control rod blade assemblies in process of fabrication was conducted.
The assemblies were visually and dimensionally inspected upon their arrival at Big Rock Point. Some radiography of the assemblies was performed to check on poison rod number and position.
Having successfully completed the various aspects of the QA program, the assemblies were placed back in their shipping containers to await use.
D.
Hazards Considerations 1.
Reactivity Excursion Analysin: Postulated reactivity insertion accidents have not changed, as the control rod worths of the new " Type 2A" control rods are identical to the " Type 2" control rods now in use.
2.
Power Distribution Control: The neutron absorption characteristics of the " Type 2A" control rods are identical to the " Type 2" control rods. No changes in power distribution control vill result.
III. Conclusions From the preceding analysis, tbe following can be concluded:
A.
The consequences of all postulated reactivity accidents vill be unchanged.
B.
There vill be no effect on present limits of heat flux, fuel temperature, or critical heat flux ratio.
Based upon this, we have concluded that the ttse of " Type 2A" control rod blades in the Big Rock Point Nuclear Plant does not present a change in the hazards consideratione described or implicit in the Final Hazards Summary Report.
CONSUMERS POWER COMP By Senior Vice President Date: January 28, 1971 Sworn and subscribed to before me this 28th day,of January 1971.
wuN Notary Public, Jackson County, Michigan My commission expires January 15, 1972
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Contact:
ic NCWS FOR IMMEDIATE RELEASE In,Rockville, Md. for NFS:
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C.
E. Fountain (301) 424-1750 In Jackson, Mich. for CPC:
Ty Cross (517) 788-0111 In New York, N.Y.
for MJH:
R.
J. Wilson, Jr.
(212) 245-5504
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NUCLEAR FUEL SERVICES TO SUPPLY FUEL TEST ASSEMBLIES FOR CONSUMERS POWER GENERATING PLANT IN MICHIGAN ROCKVILLE, Md.,
January 25 -- Nuclear Fuel Services, Inc.,
has contracted to provide plutonium fuel demonstration assemblies to Consumers Power Company's Big Rock Point nuclear power generating plant, according to a joint announcement made today by the two firms.
The cooperat.ve program calls for NFS to design, fabricate, and supply four Plutonium-Uranium fuel atsemblies which are scheduled for insertion into the Big Rock Point BWR reactor in the spring of 1973.
NFS will enploy new engineering test and fuel fabrication facilities in the design and construction of tha demonstration assem-ilies for Consumers Power.
This program is another step in NFS's planned approach to the nuclear fuel market.
Consumers Power indicated that the contract
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