ML20006C776
| ML20006C776 | |
| Person / Time | |
|---|---|
| Site: | 07000036 |
| Issue date: | 01/24/1990 |
| From: | Mccaughey D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20006C770 | List: |
| References | |
| NUDOCS 9002090124 | |
| Download: ML20006C776 (4) | |
Text
y
~~
p>
J
,i. g.,,.
e 3
[-
i
'i' 4
JAN2 4 1990 n
DOCKET NO:
70-36 LICENSEE:
Combustion' Engineering, Inc. (CE)
Hematite, Missouri
SUBJECT:
SAFETY EVALVATION REPORT, AMENDMENT APPLICATION DATED JANUARY 3, 1990. AND SUPPLEMENT DATED JANUARY 12. 1990 RE AUTHORIZATION TO ADD P0 REFORMER AND LUBRICANT TO THE NEW PELLET PRODUCTION LINES AND AUTHORIZATION TO STORE SPECIAL NUCLEAR MATERIAL ON THE SECOND AND THIRD FLOORS OF BUILDING 254
Background
On November 24, 1989, the NRC issued Amendment No.15 to Materials License No.
SNH-33 authorizing the use of uranium enriched to 5.0 weight percent in the U-235 isotope in the Building 254 pellet production lines..During the course of reviewing the amendment application, the NRC staff determined that CE-had not fully demonstrated the safety of two systems: (1)thepelletizing. process line when moderator material is added to the dry UO feed material and (2) proposed storage arrays of special nuclear material on the s$cond and third floors of Building 254 Accordingly, the amendment was issued with two conditions prohibiting
. the addition of poreformer and/or lubricant (moderators) in the Buildin,g 254 pelletizing process, and prohibiting special nuclear material in storage arrays on the second and third f1M rs of Building 254. On January 3,1990 CE submitted an amendment application updating the safety demonstration for these two systems and. requesting deletion of the two conditions. After numerous discussions with NRC staff, CE supplemented the application on January 12, 1990. CE's two submittals and the staff's review are discussed below.
Discussio_n A.
Building 254 Pelletizing Line CE performed analyses on the components of the pelletizing line to confirm' that l
combinations of special nuclear material and moderator would not cause the' i
effective multiplication factor to exceed 0.95. A pelletizing line is shown-in.
Figure 1.- The process starts on the third level at the. conical screw (pore-former) mixer. 00 is added to this mixer either by vacuum transfer from the ' '
p l
air mix blender or by 5-gallon pail addition through the poreformer and press fines recycle hood.
Poreformer is also added at this process step through this is s ur L
hood. The material then flows to a slugging press on the second level and is i
+
4. subsequently granulated.
The granulated powder flows to a lubricant mixer where l
g lubricant is added by way of the lubricant and granulated feed. hood. This material is fed to the final pelletizing step on the first level where pelletizing is-conducted in a rotary pellet press.
- 1
'Th'e first set of CE calculations was performed on an isolated conical screw
-(poreformer) mixer on the third level. The poreformer mixer is a truncated.
cone with a top inside diameter of 30 inches, a bottom inside diameter of 8 inches, and a height of 35.5 inches. - The U02 p wder transferred to the mixer 9002090124 900124 PDR ADOCK 07000036 C
PDC l
p
1 2
Figure 1 I.
u J
~
Poreformer &
eNi r ec)'el d
k;-
.*51Q'
/
(
[
hE.
i 1 hel
\\
\\/ \\
\\/
\\!\\/
t Slugging Conical 2,000 Kg Press Screw 4. Air Mix A
Wixer
' Blender g
{
i Granulator C
.S I'
I
@/.y ' ?
Lubtleant &
O m.
I l 2.. -
/ Granulated g
i' Fj.f; Feed Hood
\\f Cranulated Feed Removal Y
Hood
\\
~
/
!\\
/
t Vacuum h'ne sport Lubricant Mixer
)
7 g
Pellet j
Press I-l
- ff?d<.d' l
l dd4f+
1
s-aa---
w w
-+--eF~+-w' N1=
e-wwe=
m
--r-^"
JAN 2 41990
)
Combustion Engineering, Inc.
3 i
i will have a maximum density of 2.5 g/ce, a maximum enrichment of 5.0 w/o U-235, l
and a maximum water content of I w/o.
In the first series of calculations for the mixer, a 100 kg batch of UO, was assumed to be in the mixer, and the addition j
of poreformer was varied until the mixer volume was full. CE reported that the k-effective value reached a maximum of 0.70 when the mixer volume was full (100 kg of UO 118 kg of poreformer).
In a second series of calculations for the mixer, th$,00,, loading was assumed to vary from 75 kg to 200 kg while. the' j
poreformer loadinh was changed to maintain a full mixer volume. The reported' k-effective value reached a maximum value of 0.76 at a U0 loading of 200 kg.
7 The second set of calculations was >erformed on the entire pelletizing line.
The pelletizing line components (otier than the bulk blenders) were assumed to
}
contain a mixture of UO and poreformer in the same proportions es that which produced the maximum k $ffective value in the first series of analyses above e
a g 100 kg of UO 118 kg of poreformer). The reported CF k-effective value for this system w$s, 0.68.
Staff has reviewed these values and determined that.
CE's calculation which produced a h-effective value of 0.68 is nonconservative.
The licensee's first set of calculations produced a k effective value of. 0.70 for an isolated poreformer mixer. Therefore, the interaction analysis in the i
second set of calculations should not produce a k-effective value' less than 0.70.
CE calculations were performed using tie Hansen-Roach 16-group cross section set along with KENO IV, a Monte Carlo code. The staff used a conservative model for the pelletizing system and produced a k-effective value of 0.77.
The staff conducted independent
.. effective calculations using the 27-group cross section set which is found in SCALE, along with KENO-Va, a Monte Carlo code. Staff's calculations produced acceptable results.
Moreover, CE failed either to establish controls for limiting the use of moderating material other than poreformer and lubricant materials in Building 254 or to demonstrate that such moderation control was not necessary.
The staff analyzed the poreformer mixer by assuming the mixer is entirely filled with UD,, and optimum 1y moderated with water.
For this condition, k-effective exceeded unity.
In addition, the staff analyzed the lubricant mixer with the same assumptions. Again, k-effective exceeded unity. Accordingly, in the January 12, 1990, supplement, CE committed to limit the amount of U-235 in the poreformer mixer to 4.4 kg and moderating material (solutions and powders) to a pair of 5-gallon pails on each floor when material is in process. This limit does not include the poreformer and lubricant which was adequately limited and demon-strated to be safely suberitical by the licensee and independently confirmed by NRC staff.
The commitment to limit the amount of moderating material, however, does not provide for moderation control when the process is shutdown.
This control is necessary since it is possible for U0, to be in the system when it is shutdown or moderator could be added to an empty' system which is subsequently filled with U0,,,
Therefore, to alleviate this problem, the staff recommends the following licehse condition:
At all times, the licensee shall limit moderating material (solutions and powders), except.poreformer and lubricant, to not more than two 5-gallon pails on each of the second and third floors of Duilding 254.
m.
J3
?
y' 4
F.~;, ?
'" a'
'JAN 2 419301~ <
L Combustion Engineering, Inc.
4 j,
e J
q s
p' B.
Building 254 Second and Third Floor Storage 6
CE conducted a criticality safety assessment of special nuclear material storage
'x on the second and third floors of Building 254. The material will be stored in 5 ga11on pails (11 inches in diameter and 13 inches high). CE analyzed the.
storage configuration assuming that the material in the pails is UO at a p
density of 3.5 g/cc as well as I w/o water, I w/o poreformer, and I w/o lubricant.
The uranium is enriched to 5 w/o U-235.
CE's model intermixed these U0, buckets with 5. gallon buckets of water in a checkerboard array which was infinite in length. The array was reflected on top by 12 inches of water and on the bottom by 12 inches of concrete.
For this array, CE reported that the maximum
- k. effective value is less than 0.8 and occurs at a water bucket density of 0.25 g/cc. During the course of the review, NRC staff determined that the above analysis did not reflect the vorst-case situation.
CF had failed to analyze the effect of neutron interaction between the second and third floors. The staff's analysis of this situation produced an unacceptable k. effective value.
Accordingly, in the January 12 1990, supplement, CE committed to limit the V
storage of UO powderoneachfloorto245. gallon,orless,containersspaced on 2-foot cen,ters.
This spacing will be assured by the use of metal spacer rings. Review of this storage configuration produced k-effective values less than 0.85.
CE calculations were performed using the Hansen-Roach 16. group cross section set along with KENO.IV. The staff calculations were performed with SCALE, using the 27-group cross section set and KENO.Va.
Conclusion / Recommendation The staff concludes that the proposed activities will have no adverse effect on the public health and safety or the environment. Subject to the condition specified above, approval of the amendment application and deletion of License Conditions 36 and 37 are recommended.
The Region III Principal Inspector has no objection to this proposed action.
i WypnelSigned E4 David A. McCaughey n
Uranium fuel Section Fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, NMSS Approved by:
OIN s_
George H. Bidinger, Section Leader DFC:IMUF:
IllUF:
IM
..... y
..................../.................UF:... M d......................
l NAME:DAf cc ughey:mh:...........................[TArpe:
GHBidinger':
VL DATE:1/2L/90:
1/$/90:
1/P/90:
OFFICIAL RECORD COPY 4
i 1 1