ML20248G724
| ML20248G724 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/29/1989 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8904130546 | |
| Download: ML20248G724 (3) | |
Text
_.
Be ver Whey Power Station Shippingport, PA 15077-0004 JOHN D $1EBEH Vu:e Prescent Nuclear Group I412)643 5255 March 29, 1989 U.
S. Nuclear Regulatory Commission Attn:
Document Control Desk, Washington, DC 20555
Reference:
Beaver Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 Cycle 2 Reload Gentlemen:
Beaver.Vall ey - Power
- Station, Unit No. 2 completed the first cycle of operation on March 17, 1987 with a burnup of 16, 824 This letter describes the Cycle 2 reload design and MWD /MTU..
our' review in accordance with 10 CFR 50.59 and provides documents our determination that no technical-specification changes or unreviewed safety questions are involved.
- The Cycle = 2 core' configuration is arranged in a low leakage loading pattern ~ and involves replacing fifty-three (53) Region 1 and.three (3) Region 2 fuel assemblies with twenty (20) Region 4A
' fuel. assemblies enriched to 3.4 w/o and thirty-six (36) Region 4B fuel. assemblies enriched to 3.8 w/o.
The mechanical design of these fifty-six (56) new fuel assemblies is the same as the Region 1
assemblies except that Region 4A and 4B include the following fuel design improvements:
(1) Reconstitutable Top Nozzles, (2)
Debris Filter Bottom Nozzles, (3) Snag-Resistant Grid Straps, (4)
Standardized Fuel
- Pellets, (5) Integral Fuel Burnable Absorbers, (6)
Axial
- Blankets, and (7) Water Displacer Rods.
These changes are currently part of the licensing basis in other plants and meet all fuel assembly and fuel rod design criteria.
The Reconstitutable Top Nozzle (RTN) is different from the current design in that (a) a groove is provided in each thimble thru-hole in the nozzle plate to facilitate attachment and J
- removal, and (b) the nozzle plate thickness is reduced to provide additional space for fuel rod growth.
Along with the RTN, a long tapered fuel rod bottom end plug is used to facilitate removal and reinsertion of the fuel rods.
The Debris Filter Bottom Nozzle (DFBN) is designed to inhibit debris from entering the active fuel region of the core to i
maintain fuel performance by minimizing debris related fuel failures.
The DFBN is a low profile bottom nozzle design made of stainless steel, with reduced plate thickness and leg height.
The DFBN is structurally and hydraulically equivalent to the existing low profile bottom nozzle.
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c Beavor Valloy Powcr Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 Cycle 2 Reload Page 2 The snag-resistant grids contain grid straps which are modified to help prevent assembly hangup due to grid strap interference during fuel assembly removal.
This was accomplished by changing the grid strap corner geometry and adding guide tabs on the outer grid strap.
{
The standardized fuel pellets are a refinement to the current i
pellet design with the objective of improving manufacturability while maintaining or iraproving performance.
This design incorporates a reduced pellet length, modification to the previous dish size and the addition of a chamfer.
The Integral Fuel Burnable Absorber (IFBA) coated fuel pellets are identical to the enriched uranium dioxide pellets except for the addition of a
th.
boride coating on the pellet cylindrical surface along the central portion of the fuel stack length.
IFBA's provide power peaking and moderator temperature coefficient control.
The axial blanket consists of natural uranium dioxide pellets at each end of the fuel stack to reduce neutron leakage and to improve uranium utilization.
The axial blanket pellets are of the same design as the enriched and IFBA pellcts except for an increase in length.
The length difference in the axial blanket pellets will help prevent accidental mixing with the enriched and IFBA pollets.
Thirty-two (32) fuel assemblies will contain a total of 144 water displacer rods to control peaking factors.
Four (4) fuel assemblies will contain a cluster of eignt water displacer rods.
The remaining twenty-eight (28) fuel assemblies will use clusters of four water displacer rods.
The water displacer rods are essentially empty stainless steel tubes that are pressurized with helium.
These tubes are standard Westinghouse outer burnable absorber tubes without any borosilicate glass or inner stainless l
steel tubes inside them.
Water displacer rods have been used in j
the Point Beach plant reload core.
1 Duquesne Light Company has performed a detailed review of the Cycle 2
reload core design including a
review of the core characteristics to determine those parameters affecting the postulated accidents described in the UFSAR.
The consequences of those incidents described in the UFSAR which could potentially be affected by the reload core characteristics were reanalyzed, and i
we have verified that the reanalyses were performed in accordance with the NRC approved methodology described in WCAP-9273-A,
" Westinghouse Reload Safety Evaluation Methodology".
The standard reload methodology design codes were supplemented by use of the Advanced Nodal Code (ANC) to perform neutronics analyses for the Cycle 2 nuclear design.
The ANC code has been approved by the NRC for use in nuclear design analyses.
The effects of the reload on i
]
c Bidvar Vallcy Power Station, Unit No. 2 1
Docket No. 50-412, License No. NPF-73 Cycle 2 Reload Page 3
)
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the design basis and postulated incidents analyzed in the UFSAR were accommodated within the conservatism of the initial assumptions or were reanalyzed and determined not to exceed any previously acceptable safety limits.
No technical specification changes are required as a result of the cycle 2 reload design.
]
The NRC approved dropped RCCA methodology (WCAP-10298-A (Non-Proprietary),
June 1983]
was used for the Cycle 2 design evaluation and confirmed that the DNB design bacis is met for all dropped rod events initiated from full power.
The reload core design will be verified by performing the standard Westinghouse reload core startup physics tests.
The results of the following startup tests will be submitted in accordance with Technical Specification 6.9.1.3:
1.
Control rod drive tests and rod drop time measurements.
2.
Critical boron concentration measurements.
3.
Control rod bank worth measurements.
4.
Moderator temperature coefficient measurements.
5.
Startup power distribution measurements using the incore flux mapping system.
The Beaver Valley Onsite Safety Committee (OSC) and the
)
Duquesne Light Company Offsite Review Committee (ORC) have l
reviewed the Cycle 2 reload safety evaluation and determined that this reload core design will not adversely affect the safety of the plant and does not involve an unreviewed safety question.
Very truly yours, bb J.
D.
Sieber Vice President Nuclear Group cc:
Mr.
J.
Beall, Sr. Resident Inspector Mr. W. T. Russell, NRC Region I Administrator Mr.
P. Tam, Sr. Project Manager
)
Director, Safety Evaluation & Control (VEPCO)