ML20206H726
| ML20206H726 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 11/10/1988 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| TAC-69300, NUDOCS 8811230291 | |
| Download: ML20206H726 (4) | |
Text
a a
A ty 65' State So gpuport. PA 15077OC04
. s.xw W w2. e.o 52%
November 10, 1988 U.
S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
Reference:
Beavor Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 Spent Fucl Pool Additional Information Gentlemon:
Attached is our response to the NRC request for additional information, dated September 20,
- 1988, "Beaver Valley Unit 2-Enrichment Limitation in Spent Fuel Pool (TAC 69300)".
This information is in support of the review of our Proposed Operatil.g License Chango No. 15, dated August 30, 1988.
r Should you have any additional questions on this matter, please contact my office.
Very truly yours,
,i ep.
D.
Sieber tjVice President Nuclear Group cc:
Mr. J. Beall, Sr. Resident Inspector Mr. W. T. Russell, NRC Region I Administrator Mr.
P. Tam, Project Manager Mr. T. M. Gerusky, Bureau of Radiation Protection Director Mr. R. Janati, Bureau of Radiation Protection s01113~
ggit:Kes91cuosoo80!a o',
ih e
ATTACHMENT 1.
Question Describe the fabrication process for the Boraflex assemblics.
Indicate whether a
single shcot or multiple shoots of Boraflex were used in each poison assembly.
Also, indicate whether or not the Boraflex shoots are fastened to or permanently glued onto any surface or structuro.
Response
".no spent fuel storage racks at Boavor Valley Unit 2 contain single shoots of Boraflex neutron absorbing material which are installed in the four double wall compartments of each fuel storage cell.
The Boraflex shcots encased between each of the l
doubic wall stainicss stool poison retainers is not restained with glue or any other fastening machanism.
2.
Question Describe the measuring techniques for detecting degraded Boraficx specimens in the inservice surveillance program.
Response
Duquesne Light Co.
intends to use the neutron absorber surveillanco program provided by the supplier of the spent fuel storage rachs.
The examination methodology includes visual examination, hardness measurement, dimensional re.casurement, and weight measurement.
An EPRI report concerning noutron absorber surveillance program development guidelines is expected in December 1983 and will be reviewed by Duquesne Light Co. for applicability to Beaver Valley Unit 2.
The Duquesne Light Co.
will remain cognizant of the most recent technical advances in the Boraflex surveillance arca and adjust or modify the Unit 2 Surveillance Frogram as necessary.
3.
Question Describe the correctivo actions to be taken if degrtded Boraflex specimens or absorbor is found in the spent fuel pool.
Responsa Duquesne Light Co.
intends to review the surveillanco program results and take corrective action should degraded Boraflex be indicated.
Potential remedial measures will be developed based upon the most recent industry experience, research results and state of the art technology available at that time.
t I
Aitcchmsnt
- Pcgo* 2 4.
Question Describe how the sub-region of Region 1 which can presently store fuel up to 3.6 weight percent U-235 with no physical restrictions will be distinguished and separated from the sub-region of Region 1
which will store fuel with enrichments higher than 3.6 weight percent in a 3 out of 4 configuration.
Response
There are no sub-regions in Region 1 p'.c Region 2.
Spent fuel i
pool Region 1
will provide for stcrago of fuel with enrichments up to 4.85 w/o in a physically and administratively controlled 3 l
of 4 cell array.
Region 1 will be distinguished form Region 2 by the presence of fuel cell covers installed in 1 of 4 Region 1 e
fuel cells and it will be designated Region 1 on the fuel pool map in the Refueling Procedure.
Region 2 will have no fuel cell covers and it will be designated Region 2
in the Refueling Procedure.
5.
Question In order to prevent fuel loading errors in spent fuel pools with storage configuration restrictions, the staff has previously requested physical blockage of storage locations which are prohibited from containing any fuel.
Ficaso discuss the acceptability of physically bioching the 4th cell in cach 3 out of 4
cell array in Region 1
rather than tolying solely on administrative procedures to prevent misloadings.
Rosponse Region 1
spent Fuel Cells will have physical barriers inserted into one of four fuel cells.
These barriers will prohibit insertion of any fuel assemblics while allowing storage of fuel assembly inserts such as Thimble Plugs.
6.
Question What is the reactivity offect of noglecting the axial and radial distribution of burnup in the Region 2 fucl assemblics?
Response
The reactivity effects of the fuel assembly axial and radial burnup distributions have not bocn neglected in the Region 2 reactivity calculations.
Atta' chm 3nt Pago 3
- 6. Response, continued The Region 2
burnup credit analysis is performed using a 2-D model of a
complete fuel assembly without axial leakage.
As a
- result, the burnup credit criticality analysis for the Region 2 spent fuel racks explicitly includes the fuel assembly radial burnup distribution in the calculational models.
To address the effects of the fuel assembly axial burnup distribution, a study was completed by Westinghouse in 1979 which evaluated the impact of the fuel assembly axial burnup distribution on the fuel rack reactivity calculations.
For these calculations, the most skewed burnup distributions were obtained from 3-D assembly depletions.
An axially uniform burnup distribution and a
skewed burnup distribution were compared at different burnups.
The results show that the effect of the axial burnup distribution is insignificant and can be ignored in spent fuel storage reactivity calculations.
7.
Question Discuss any procedures or physical restraints which require the movement of fuel to non-burnup dependent locations before moveracnt to burnup dependent racks.
Responso There are no requirements to move fuel to non-burnup d? pendent locations (Region 1) before movement to burn-up dependent locations (Region 2).
The movement of a
fuel assembly is Administratively Controlled by saveral methods.
- First, the Nuclear Material Control Manual requires Plant flanager or his designce authorization prior to movement of any fuel assembly.
The authorization record, the "Nuclear Material Transfor Record" (NMTR),
specifics the Region the fuel assembly is authorized to be moved to.
In addition, the Refueling Procedure will specify the Region and specific fuel location that cach fuel assembly will be moved to.
These locations will be verified to be in accordance with requirements of proposed Technical specification 3.9.14.
8.
Question Should revised Technical Specification 5.6.1 refer to the UFSAR rather than the FSAR?
Responso Yes.
-