ML20033A929
| ML20033A929 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 11/16/1981 |
| From: | Prelewicz D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.), NUS CORP. |
| To: | |
| References | |
| ISSUANCES-OLA, NUDOCS 8111300171 | |
| Download: ML20033A929 (6) | |
Text
.
n-7 Ewa ce;2mm=cE e
b
~~
UNITED STATES OF AMERICA
+
NUCLEAR REGULATORY COMMISSION 00'gETE0 2
IN 23 P5:10 BEFORE THE ATOMIC SAFETY AND LICENSING BO
> SECRETARY In the Matter of
)
EIfiG & SERVICE
) Docket No.' SbS155-OLA CONSUMERS POWER COMPANY
) (Spent Fuel Pool
)
Mcdification);Ij 'd
\\
5 9 ' '-
j (Big Rock Point Nuclear Power Plant)
)
j%
n "j?f' b/
b d,% ;l'i((d 'ej AFFIDAVIT OF DR. DANIEL A. PRELEWICZ County of Montgomery )
i
" /S(f
^
Idyt
[
) SS q,
t State of Maryland
)
7;,
y, I, Daniel A. Prelewicz, Manager of the Safety Ana Department at NUS Corporation, of lawful age, being first duly sworn, upon my oath certify that the statements and infor-mation contained in the five-page Statement concerning O'Neill Contention IB-5 are true and correct to the best of my knowledge and belief.
Executed at Rockville, MD.
A.
m
}
)3h J b. V G.l x Subscribed and sworn to before me this 16th day of November, 1981.
Notary Public in a d fo.the State of Maryland and the County of Mont-gomery i
My cc:amission expires po3 5
ill 8111300171 8111
{DRADOCK05000 55 PDR
~
o UNITED' STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
)
)
Docket No. 50-155 OLA CONSUMERS POWER COMPANY
)
(Spent Fue7 Pool
)
Modifica'_ ion)
(Big Rock Point Nuclear Power Plant)
)
STATEMENT OF DANIEL A.
PRELEWICZ CONCERNING O'NEILL CONTENTION IB-5 My name is Daniel A. Prelewicz.
I reside at 6901 Keats Court, Reckville, Maryland.
Since June 15, 1978, I have been employed by NUS Corporation, an engineering services firm in Rockville, Mary-land.
I am currently Manager of the Safety Analysis Department at NUS.
My professihnal qualifications were described and are set forth in my Affidavit which was submitted in connection with-Con-sumers Power Company's Motion for Summary Disposition with respect to Christa-Maria Contention 8 and O'Neill Contention IIIE-2.
The purpose of my Affidavit is to describe the calculation of the bul.k coolant temperature that exists in the Big Rock Point spent fuel pool assuming its present capacity for the storage of spent fuel and the proposed expansion of the pool to accommodate 441 fuel assemblies.
These bulk coolant temperatures are needed in order for Messrs.
Sacramo and 31rkle to determine whether or not the cor-rosion and/or degradation of the spent.2el pool materials increase
. - in any significant matter as a result of expanding the spent fuel storage capacity as alleged in O'Neill Contention IB-5.
The effect of fuel pool expansion on thermal gradients in the fuel racks is also shown to be insignificant.
INTRODUCTION Heat is generated in the spent fuel pool by radioactive decay of fission products.
This heat is removed from the pool water by 6
two heat exchangers e..;h with a rated capacity of 3 x 10 BTU /hr.
The actual amount of heat removed by the heat exchangers increases with the temperature of the pool water.
As more heat is generated, the temperature of the pool increases until the heat exchangers are removing heat at the same rate as it is being generated in the por'_.
The amount of heat generated by a particular fuel bundle depends upon the length of time the bundle has been removed from the reactor core.
The earliest that a fuel bundle would be moved to the pool is two days after the reactor is shut down.
Decay heat generated in the bundle after two days is about 0.4% of the full power heat load.
This heat generation decreases to less than one-tenth of the two day heat load after one year, and to less than one-fiftieth of the two-day heat load after ten years.
Hence, the heat generation in the pool is predominantly due to the fuel which was most recently placed l
in the pool.
l The storage capacity of the Big Rock Point spent fuel pocl is i
proposed to be increased from 193 assemblies to 441 assemblies.
Storage of the additional assemblies in the pool will result in a l
l l
I l
l l
9 small increase in maximum pool bulk coolant temperature.
The effect of increasing the capacity of the spent fuel pool is to permit the storage of more old or decayed spent fuel which generates only a small amount of additional heat.
This is due to the fact that the predominant heat source is a fresh core discharge of fuel, either full core or normal refueling, which is always assumed for purposes of analysis regardless of the capacity of the pool.
SPENT FUEL POOL HEAT LOADS AND TEMPERATURES The heat loads in the spent fuel pool were calculated for both the present fuel pool with a maximum capacity of 193 assemblies and the expanded pool with a capacity of 441 assemblies.
In each case, the maximum heat loads were calculated for a full pool (i.e., all storage spaces occupied) following a normal refueling each year, and normal refuelings followed by a full core offload.
A normal refueling consists of twenty-two assemblies placed in the pool two days after shutdown, while a full core offload is taken as 84 assem-blies placed in the pool two-days after shutdown following six months of reactor operation since the last refueling.
The methodology of NRC Standard Review P:sn 9.2 was used to calculate the heat gene-rated by the spent fuel.
Results of the calculation:. show that the maximum heat generated 6
in the fuel pool following the full core offload is 3.79 x 10 BTU /hr.
6 for the expanded pool configuration and 3.59 x 10 BTU /hr. for the present pool configuration.
For normal refueling cycles until the 6
pool is filled, the maximum heat generated is 1.37 x 10 BTU /hr.
.9-.
,---,,-c e.e, y.
,.v 4
w
6 for the expanded pool configuration and 1.09 x 10 BTU /hr. for the present pool design.
Based on the heat exchanger-performance characteristics, the maximum fuel pool temperature is approximately 101*F for the expanded fuel pool configuration following a full core offload, as compared with approximately 99'F for the present fuel pool capacity.
For the normal refueling sequence, the maximum bulk coolant temperature is 93*F for the expanded fuel pool configuration, as ccmpared with approx-imately 88'F for the present fuel pool capacity.
Thus, the maximum bulk coolant temperature following a full core offload will increase by approximately 2*F, while the maximum bulk coolant temperature for normal refueling cycles will increase by approximately 5'F.
The nor-mal refueling maximum temperatures of 88'F and 93'F are consistent with the (95'F) temperature used in the Affidavit of Dr. John R. Weeks.
The above results were used to assess the stresses and corro-sion rates of the materials identified in O'Neill Contention IB-5 due j
to the expansion of the spent fuel pool.
These considerations are discussed in the Affidavits of Mr. Sacramo and Mr. Birkle, respectively.
THERMAL GRADIENTS IN FUEL RACKS i
Thermal stresses may be induced in spent fuel racks by tempera-i ture gradients between the inside and the outside of the racks.
The i
l coolant on the inside of the racks is heated by the spent fuel, while the coolant on the outside is not.
These gradients are not affected by changes in the bulk coolant temperature such as those discussed i
j in the previous section.
An increase in the bulk coolant temperature i
L.
- raises the temperature.of the coolant on both the inside and outside of the rack.
The magnitude of the gradient is determined by the heat generat-ed in an individual fuel bundle.
Th'is quantity does not change with the pool expansion. 'Hence the gradient in the existing aluminum racks will not be affected by the' expanded storage.
Stresses ieduced
'by the thermal gradient are considered in the design of the new fcel racks.
.