ML19260D209
| ML19260D209 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 01/24/1980 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML19260D200 | List: |
| References | |
| NUDOCS 8002080112 | |
| Download: ML19260D209 (11) | |
Text
.
I UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD IN THE MATTER CF
)
)
COMMONWEALTII EDISON COMPANY
)
Docket Nos. 50-295
)
50-304
)
(Zion Station Units 1 and 2)
)
)
Proposed Isendments to
)
Increase Spent Fuel Storage
)
Capacity (4 3 F.R.
30938)
)
STATE OF ILLINOIS
)
)
SS.
COUNTY OF C O O K
)
AFFIDAVIT OF TOM R. TRAMM I,
TOM R. TRAMM, of lawful age, being first duly sworn, upon my oath certify that the statements contained in the attached pages and accompanying exhibits are true and correct to the best of my knowledge and belief.
NNs I Tom R.
Tramm SUBSCRIBED AND SWORN TO before me this cpra day of January, 1980.
<?
M n -u_ e R 2 W W1W
-n ary Public
[2p N7/.
My commission expires
/
1942 209 Poo 2 c ro t te
I.
The Board has asked the carties to address in more depth the questions of whether or not the water in the Zion spent fuel pool would be a " stagnant, oxygenated borated water system," as defined by the NRC Staff on page 3 of of I.
E.
Bulletin No. 79-17, Revision 1, dated 29 October 1979; and whether the water inside the proposed vented fuel storage tubes would be a " stagnant oxygenated borated water system," and, if so, what would be the effect on the fuel storage tubes and racks.
I.
E.
Bulletin 79-17, Revision 1 states:
For this review, the term " stagnant, oxygenated borated water systems" refers to those systems serving as engineered safeguards having no normal operating functions and contain essentially air saturated borated water where dynamic flow conditions do not exist on a continuous basis.
As I stated in my November affidavit, the water in the spent fuel pool constantly circulates due to the operation of the spent fuel pool cooling system and natural convection heat transfer around the stored spent fuel assemblies.
Therefore, although the pool dc.
.antain is generally not stagnant.1!
oxygenated, borated water, it More detail is supplied below.
1/
The spent fuel pool is not identified as an " Engineered Safety Feature" in the Zion FSAR.
Generally the term "encineered safeguards" used in I.E.
Bulletin 79-17, Res. 1 connotes systems designed to protect the reactor itself rather than auxilliary systems such as the spent fuel pool.
1942 210
Normal inlet flow to the spent fuel pool, when one spent fuel pool cooling system pump is operating is 2300gpm, but this flow is increased to about 4600gpm when both spent fuel pool cooling systems pumps are operated during re-fueling.
Average velocities at the inlet pipe are 9.4 and 18.8 feet per second for these two conditions.
At these rates, each of the spent fuel pool cooling system pumps will pass an amount of water equal to the entire pool volume every five hours, and both pumps operating together will
" turn over" the pool volume in about 2-1/2 hours.
These are slightly conservative estimates because they ignore the independent contribution of the pool skimmer system, which takes in pool water at 50gpm.
Cooling water for the pool enters through a ten-inch pipe at the north end of the pool.
The pipe enters at the top of the pool and directs flow to the bottom of the pool.
Two ten-inch pipes at the south end of the pool take water from a point near the surface of the pool to the spent fuel pool cooling system.
Thus the pumped flow path within the pool is generally from the bottom of the north end of the pool to the top of the south end of the pool.
Natural circulation adds to this flow pattern, especially in fuel racks in which spent fuel is stored.
Water is heated in the fuel storage tubes by decay heat from spent fuel.
The heated water is less dense 1942 211 than the surrounding and cooler water and therefore rises.
Cooler water is drawn up into the tubes from the seven-inch plenum area below the racks.
The warm water rising out of the tubes cools as it mixes with the large volume above the fuel racks.
Water from this volume is drawn back down to the plenum beneath the racks via the spaces between indi-vidual racks and between the racks and the pool walls, through empty fuel tubes, and through tubes which contain spent fuel which has been stored for a long time and there-fore is relatively cool.
If you look at the pool after a recent refueling discharge, you can see the heated water welling up out of the storage tubes where the hot fuel is located.
Thus the pool water in general and the water in the spent fuel tubes in particular will not be stagnant.
A weak convective flow can be predicted to occur within the walls of the fuel storage tubes themselves.
On each side of the tube, near the top, is a 1/4 inch vent hole through the inside stainless steel tube wall which will allow pool water to go inside the tube walls.
- However, the tube walls are vented only at the top so there is no chance for pumped or convective flow in the bottom and out the top.
Water which enters a heated tube wall via the vent hole would convectively circulate within the wall spaces, probably up the flats and down the corners.
This effect is not expected to be strong for two reasons.
First the tight 1942 212 clearances within the tube wall restrict flow.
- Second, convective flow through the center of the tube effectively carries off most of the heat radiated by the stored spent fuel, reducing the heat load on the tube walls.
Therefore, I expect that the water within a heated tube wall (that is, the wall of a tube in which a spent fuel assembly is stored) would be nearly stagnant.
Water within an unheated tube wall would be essentially stagnant.
In response to the Board's order and Dr. Staehle's suggestion, we have reviewed in even more detail the geometry of the racks to look for other crevices or pockets which might contain stagnant water.
As you can see from the attached drawings,2/ there are spaces between the outer surface of each tube and the outer surface of the adjoining tube.
These spaces between tubes are about one inch wide.
These spaces are closed to lateral flow by the long flat joining strips which hold the tubes together.
Some of the joining strips don't run the entire vertical length of the tube, but most of them do.
At the bottom, the spaces between tubes are generally closed to vertical flow because the tubes stand on the base plate and the only holes in the plate are the five inch flow holes inside each tube.
The top of these 2/
Exhibit 1 i.c taken from the Zion Licensing Report, which was introduced as evidence in the hearings.
Exhibit 2 is the same drawing which was attached to my November affidavit, with the addition of the cautionary note that the space between tubes is not drawn to scale.
Neither drawing shows the small flares at the top of the tubes.
1942 213 i
spaces are somewhat restricted.
Approximately the top 3/4 inches of each side of each tube is flaired outward and joined to the flair of the adjoining tube.
The purpose of these flairs is to make inserting spent fuel in the tubes easier.
The flairs leave about a 2-1/2 square inch opening at the tube corners.
This space allows free communication between water in the spaces between the tubes and the water in the rest of the pool.
There is no opening at the bottom so vertical flow through these spaces between tubes is prevented.
Ac with the water within the tube walls, con-vective flow will occur to a limited extent in spaces between tubes which contain spent fuel assemblies.
This effect is expected to be small and the water in these spaces as well is probably nearly stagnant.
The full penetration structural welds which run from top to bottom along one side of the stainless steel outer sheath of each tube will be exposed to this water, as will most of the structural fillet welds which are used to attach the tubes to joining strips and to the base plate.
II.
Previously I had testified that a chemical analysis test was being utilized by the Boral manufacturer, Brooks &
Perkins, to determine the B10 loading in the absorber material.
This test is performed for each Boral batch by destructively sampling coupons as I had described.
Each Boral plate is 1942 214
identified with a serial number traceable to the coupon, and the chemical test.
The accuracy of the chemical analysis test is verified by the results of a neutron attenuation test performed using the neutron beam of the University of Michigan reactor.
(Tr. 1940-2).
In the intervening months the quality assurance program has identified several instances, that the serial numbers have been incorrectly transferred from the plates to the documentation, and again back to the plates.
No Boral plates or fuel storage tubes have been accepted or sent to Leckenby for manufacturing storage racks at this time which have this problem.
Approximately four to five percent of Boral plates have been affected.
Errors occur due to the lengthy serial number, and the many times the number must be transferred to documentation and the plates during manufacturing steps.
The errors have been found through the several inspection steps and reviews of documentation required during the manu-facturing process as part of our QA activities.
Brooks &
Perkins is in the process of implementing corrective action to reduce the length of serial numbers and the amount of manual number transfers.
Due to tl.e loss of chemical composition traceability for this portion of the Zion boral plates, we are approving an alternate, nondestructive testing procedure which uses 1942 215
I the University of Michigan reactor neutron beam to establish the neutron attenuation properties of individual plates.
The minimum acceptable attenuation factor used is.9400, which 2
corresponds to a boron-ten loading of.0200 gm/cm.
The accuracy of the neutron attenuation test is controlled by the accuracy of the neutron detector and the electronic counting devices.
The counting error is less than.10% within a 95% confidence level.
The neutron attenuation test will demonstrate the acceptability of each Boral plate tested for neutron attenuation.
It is important to recognize that all lots of raw materials used in the manufacture of the Boral are still identifiable and fully certified.
Traceability has only been lost insofar as it is not possible to establish for certain plates, the specific lots of raw materials from which these specific plates were fabricated.
III.
We have recently received I.E.
Information Notice No. 80-01 which describes two recent fuel handling events, both of whicn occurred at the Pilgrim Nuclear Station, a Boiling Water Reactor.
The events both involved utilizing the overhead crane to conduct fuel handling operations in the storage pool.
In the first event, an assembly was withdrawn too close to the pool surface resulting in a 1942 216
radiation alarm.
In the second case, an assembly was dropped onto the lifting hooks of four assemblies, which in this case, protruded above the storage racks.
These events have been reviewed and it has been determined that they do not apply to the proposed Zion Storage Rack modification.
As I previcusly testified, all fuel handling operations required during the reracking modification will be conducted using the spent fuel pool bridge crane, rather than the overhead crane.
Using the bridge crane, it is not physically possible to withdraw a fuel assembly from the pool due to the limit on the lifting height resulting from the length of the fuel handling tools.
1942 217
9 O'
- x AT
/-
/
/
I
. '\\h
/
'5
/
/
ek
.%v N..q-:'.k:>s.. /.. 'N s
N s.
a-s I,g y
d:n??:L _ Kl-;::..' % ' '2. )
Gy v
/
xD A. 3 '. ',
g
~
,,,Y. /;'.
?
Q 9
,/.
... ' w ye _,
,..,p %,., % s <
,s..
.x s..,
%.,r w., s..,r, y.
+
.,/
c r
.-...s.,,., - ~..
...>:ac,,. %...,-r
.. /
,.., - o
~
8 s
t,.,,- ~r,, e s,....-%
. ~, -
- w. r%,
r\\
j' *. y;^' '. n,. J %,.y- % r *,,,f'...,..%,L,r .* y, F'%-
'%, /
f
~^*
% <v%.g?%,./7'.el/' Af:},.,. p u.;,.,
,.,.;, w,. ~,,,'- <,.',' %,.'T ;*a:.g '.-+,..,, q.,y %..p-
-af l
,es
.. ~
g j...4,. i,. c g.7%
,r4.,. 47
~
,,,. ),.%.4.,,,/3,,,,4w,..+ -,A,,m_, A+..,%q;3,.9 p.
l t. I.,sW
,.,-.g
, t. >
j
-: ? g r^&7' %,W ~g.y' %u,d 4
.Ls y,
.,, pm-zg., ~ %;
<. yr,
,rs.
.-r l
<t'
.: :v i
9, 170.3 s
i i
I, l
I i
6.
i c
a s s l
- s.,*,/,
.w=,
~
, A,,
.(.
',%f -
(
5 6
~.
.q.-
r
.:. nir : :c::: la t'
irchas FIG'E 3. 2. 2.
h' 10 3PT.'iT FU'.t. R C:'
7,..)
. :,r e I
.l'.
(,
t.i16.
44L -
M
'Vh, *t" 1 -/
1942 219 1942 218
's p
1 i
L,~~
~
ll JF
-~
k,
~~
E J
t 1
"f1 1l
..__,1, :
,J
._. a 1
O-J--
b-r 1
L_3,.
J;'
1
--F 1
r E-L J --
Jr-il e
l1' 1-b 15
'h g
"~
e t.,
~
r
- ?
k 2
I
.b
['!
F 1942 220 i
.h 4
I}i h
R tr. d I-7 YO
- s....y o
UNITED STATES NUCLEAR REGULATORY COMMISSION o
{
I REGION lli 8
7P9 ROOSEVELT ROAD s
'g g
OLEN ELLYN. lLLINO15 80137 J.W.OS EU JAN 4 P8r CD WP9 Docket Nos. 50-10, 50-237,30-249, RFT 50-254, 50-265, 50-295, 50-304, 50-373,
'WP 50-374, 50-454, 50-455, 50-456 and 50-457 Commonwealth Edison Company ATTN:
Mr. Cordell Reed Vice President Post Office Box 767 Chicago, IL 60690 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter. It is expected that recipients will review the infor-mation for possible applicability to their facilities. No specific action or response i:: requested at this time.
If further NRC evaliations so in-dicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely,
'k m b bgf k
/JamesG.Keppler Director
Enclosure:
IE Information Notice No. 80-01 cc w/ encl:
Mr. D. L. Peoples, Director Mr. Gunner Sorensen, Site of Nuclear Licensing Project Superintendent Mr. B. B. Stephenson, Mr. R. Cosaro, Project Station Superintendent Superintendent Mr. N. Kalivianakis, Central Files Mr. N. Wandke, Station
~ Director, NRR/DPM Station Superintendent Director, NRR/ DOR Superintendent PDR Mr. L. J. Burke, Site Local PDR Project Superintendent NSIC Mr. T. E. Quaka, Quality TIC Assurance Supervisor Mr. Dean Hansell, Of fice Mr. R. H. Holyoak, Station of Assistant Attorney Superintendent General 1942 221 w
~
l f1
,f
- ./
e UNITED STATES SSINS NO.: 6870 NUCLEAR REGULATORY COMMISSION Accessions No..
OFFICE OF INSPECTION AND ENFORCEMENT 7910250523 WASHINGTON, D.C.
20555 January 4, 1980 IE Information Notice No. 80-01 FUEL HANDLING EVENTS Description of Circumstances:
Two recent fuel handling events at the Pilgrim Nuclear Station have been reported to the NRC wherein there were no interlocks to control or limit the movement of nuclear fuel in the reactor building.
The first event occurred on December 11, 1979 when a spent fuel assembly was inadvertently raised high enough in the fuel pool to activate area radiation alarms. The reactor building overhead crane was being used to move new fuel from the inspection rig to the high density storage racks in the fuel pool.
After the release of a new fuel element, the lifting hook became caught between the lifting bail and the assembly channel of a spent fuel assembly. The operating personnel were unaware of the fact that the spent fuel assembly was being raised until radiation alarms sounded. The operators quickly lowered the assembly to clear the radiation alarms and ultimately placed it in a storage position. The licensee subsequently increased the administrative controls on fuel handling activities by assigning more personnel and limiting concurrent duties.
On December 17, 1979, the second fuel handling event occurred at Pilgrim Nuclear Station when a new fuel assembly was dropped while it was being transferred to its storage location in the spent fuel pool. The assembly was being transported with the reactor building overhead crane when it struck the top edge of the high density fuel racks and the latching device on the auxiliary hook failed to retain the fuel assembly lifting bail in the hook. The assembly fell, striking the lifting bails on four spent fuel elements, then coming to rest on the top of the fuel racks. It has since been moved to a spent fuel preparation stand; an inspection of the assembly will be made at the site and then it will be returned to the supplier for further evaluation. A visual inspection of the four spent assemblies was performed and there was no apparent damage. Samples of the fuel pool water were analyzed and no change in activity levels was detected. The licensee has terminated the use of contract personnel and will use members of the plant operating staff for future fuel handling operations; a licensed Nuclear Plant Operator (NPO) will be responsible for proper alignment of the crane before fuel movement and a Reactor Engineer will supervise all fuel movement. All fuel movement will be limited to the minimum speed of the crane.
The events described above occurred at a boiling water reactor, however, the patential for raising a spent fuel element with the new fuel elevator may also exist at some pressurized water reactors. Movement of spent fuel by cranes or i942 222
IE Information Notice No. 80-01 January 4, 1980 Page 2 of 2 mechanisms intended for use on new fuel, which are not interlocked to pre vent withdrawal from the pool, have the potential for producing extremely high dose rates or resulting in fuel damage.
This IE Information Notice is provided as an early notification of a possibly significant matter that is still under review by the NRC staff.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If NRC evaluations so indicate, further licensee actions may be requested or required.
No written response to this IE Information Notice is required.
If you have any questions regarding this matter please contact the Director of the appropriate NRC Regional Office.
Enclosure:
List of Recently Issued IE Information Notices 1942 223
~
IE Information Notice No. 80-01 Enclosure January 4, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 79-37 Cracking in Low Pressure 12/28/79 All power reactor OLs Turbine Discs and cps 79-36 Computer Code Defect in 12/31/79 All power reactor OLs Stress Analysis of Piping and cps Elbow 79-35 Control of Maintenance 12/31/79 All power reactor facilities and Essential Equipment with an OL or CP 79-34 Inadequate Design of 12/27/79 All holders of power reactor Safety-Related Heat OLs and cps Exchangers 79-33 Improper Closure of 12/21/79 All power reactor facilities Primary Containment holding OLs and cps Access Hatches 79-32 Separation of Electrical 12/21/79 All power reactor facilities Cables for HPCI and ADS holding OLs and cps 79-31 Use of Incorrect Amplified 12/13/79 All holders of power reactor Response Spectra (ARS)
OLs and cps 79-30 Reporting of Defects and 12/6/79 All power reactor facilities Noncompliance, 10 CFR Part 21.
holding OLs and cps and vendors inspected by LCVIP 79-29 Loss of NonSa fety-Related 11/16/79 All power reactor facilitics Reactor Coolant System holding OI.s or cps Instrumentation During Operation 79-28 Overloading of Structural 11/16/79 All power reactor facilities Elements Due to Pipe Support with an OL or CP Loads 79-27 Steam Generator Tube 11/16/79 All power reactor facilities Ruptures At Two PWR holding OLs and cps Facilities79-12A Attempted Damage To New 11/9/79 All Fuel Facilities, Fuel Assemblies research reactors, and power reactors with an OL or CP 1942 224