ML20002E315
| ML20002E315 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 01/16/1981 |
| From: | Garrity J Maine Yankee |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| FMY-81-04, JHG-81-07, JHG-81-7, NUDOCS 8101270368 | |
| Download: ML20002E315 (5) | |
Text
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MAME hiiUARHEE Om2ICPCl'JERCCMPARS*
,uaug[?,in"g ojs M) W N January 16, 1981
-i (207) 623-3521
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JHG-81-07 O
FMY-81-04 B.3.2.1 i
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Uniteo States Nuclear Regulatory Cor.iission wasnington, D. C. 20555 Attention:
Mr. Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
References:
(A) License No. OPR-?5 (Docket No. 50-309)
(B) MYAPC Letter to USNRC, dated September 30, 1975, (WMY75-ll2)
(C) UNSRC Letter to MYAPC, dated Octcoer 31, 1975 (D) MYAPC Letter to USNRC, dated September 29, 1980 (WMY80-136)
(E) USNRC Letter to MYAPC, dated Decemoer 8, 1980
Subject:
Modified Spent Fuel Pin Storage with New 10.5" Center Racks
Dear Sir:
Your let'er, reference (E), requested additional information to enaole comoletion of your review anc evaluation of the radiological aspects of our suonirtal, reference (D).
It is important to note tnat Maine Yankee has prior experience.vitn removal and disassembly of spent fuel racks. Amendment 11, reference (C),
autnorized Maine Yankee to increase the capacity of its spent fuel pool by replacing the then existing racks with densified racks.
In our letter, reference (';;, ae Driefly descrioed the procedure to be follovec in the l
removal ano disposal of the original racks.
l Responses to your request for additional information have been prepared with tnis prior experience taken into consideration.
Given below are the responses to tne questions of reference (E).
1 Ouestion 1:_
with respect to removal and disposal of tne presently installed contaminated low density racks and installation of the new hign density l
racks please provice tne following information:
(1) Describe tne method that will be used to remove and dispose of tne olo racks (i.e. crating intact racks or cutting and crumming them) and installing the new ones.
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United States Nuclear Regulatory Commission January 16, 1981 Attn: Office of Nuclear Reactor Regulation Page Two (2) Provide a table for each operation performed in (1) above giving the following information:
(a) the number of workers required for each phase of tne operation, including divers, if necessary; (o) the dose rates they will be working in; (c) the occupancy times for each dose rate; (d) the total man-rem to complete the operation.
Include any operation to be performed that would be used as a dose reduction step curing the modification.
Answer to OJestion 1, Part 1:
The following typifies the steps involved in the removal and disposal of existing racks and installing new ones:
- 1. The spent fuel will ce removed to another location in tne spent fuel pool using the customary spent fuel pool handling tools and methods. When tne new rack is installed in the spent fuel pool, the fuel will be moved to that rack.
None of the spent fuel assemblies will leave the spent fuel pool or ce stored in other than approved spent fuel storage racks.
2.
The old rack will be removed using tne spent fuel cask handling crane and lifting tools essentially by reversing the steps used to install them in the previcus reracking program.
No underwater work is necessary except some simple manipulations which can be done from above the surface of the pool.
As the rack is lifted to the pool surface it will be washed to remove loose surface contamination before leaving the pool area.
The rack will ce moved from the spent fuel pool area using tne spent fuel cask handling crane through a roll-up-door, into the Radiation Control Area.
This is done in a single continuous lift.
Prior to disassemoly or cutting up in the RCA building the rack will be set into a plastic housing, lined with a flame proof material.
The plastic housing will be vented to the RCA filter system.
3.
The new rack will be moved into the fuel pool area through the roll-up-door using the spent fuel pool cask handling crane.
The new racks will be lowered into the pool and positioned.
Again no underwater work will~ De required to ready them for use except possioly some simple manipulations performed from.above the pool surface with remote tools.
- 4. The old rack will be cismantled and cut into pieces compatible with shipping containers.
The poison cans may be saved for re-use.
5.
The pieces from the cut rack to be disposed of will be packaged as LSA waste.
The package will then ce filled with other-LSA waste l
material and shipped to a licensed burial site using standard operating procedures.
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United States Nuclear Regulatory Commission January 16, 1981 Attn: Office of Nuclear Reactor Regulation Page Three i
Througnout the different operations involved in replacing the racks, i
personnel will be using protective equipment appropriate to the radiation environment actually encountered, specified in accorcance with Maine Yankee's personnel exposure control policies and prececures.
Answer to Question 1. Part 2:
4 The personnel exposure per rack removed and disposed of is expected to De between 0.800 and 0.850 man rems, (see Table I). The total number of racks to be removeo is 13.
The total personnel exposure for all racks is thus expected to be between 10.400 and 11.050 man-rem.
Question 2:
1 Demonstrate that the metncd used for removal ano disposal of the old racks will provide as low as is reasonaoly achievable exposures to personnel performing the operations.
If compaction of racks by cutting and drumming is i
the alternative selected as your cisposal method, please provide the man-rems that may ce incurrec as ccmpared to shipping the racks intact and show that this alternative is cost effective with respect to ALARA exposure criteria, and acequacy of curial soace.
Answer to Question 2:
1 Witn respect to disposal of the racks to be removed and the personnel l
l exposures associated with volume reduction by cutting, it should be noted that I
this cperation is expected to result in relatively low ex osure, as snown in I
taole 1.
The absolute upcer bound of cose recuction that can be achieved oy alternative oisposal and snipping senemes is 0.700 man-rem per rack.
Tnis cose recuction, of course, cannot be fully achievec because some exposure will result in any scheme for packaging and cisposal.
citernatives such as shipping racks intact would thus result in minimal reductions in already low exposure estimates at tne cost of undesiracle usage of burial space and increased packaging and snipping costs The methed of recucing the volume of the racks by cutting was cescriced because we nave experience with it gained in the previous reracking program However, at tne time the racks are removed conditions may be such that shipment and disposal of intact racks is feasible and not unreasonably expensive.
In that case, ALARA consideratons would make intact rack shipment the preferred method.
The alternatives will be re-evaluated at that time.
The steps descriced in the answer to Question 1 are responsive to our responsibility to make every reasonable effort to maintain radiation exposures, anc releases of racioactive materials as low as reasonably achieveable.
r Unitec States Nuclear Regulatory Commission January M.1981 Attn: Office of Nuclear Reactor Regulation Page 4
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Conclusion:==
The methoos cescribed above will allcw the ALARA cojective to De met, will allow demands upon scarce disposal resources to be 'ninimized and. vill preserve the cption of reuse of existing poison cans if this proves feasible.
We trust this information is satisfactory; however, if you have any additional questions, please contact us.
Sincerely yours, MAINE YAtKEE ATOMIC POWER CCMPANY John H. Garrity, irector Nuclear Engineering and Licensing JHG/bjp Enclosure l
l l
SPENT FUEL RACK REPLACEMENT i
TOTAL RADIATION EXPOSURE PER RACK OPERATION NO. OF WORKERS DOSE RATES JOB DURATION TOTAL EXPOSURE
- 4 1-3 mr/hr Typical Move Fuel 2
General Area 2d 0.040 Man Rem /
j 10 mr/hr Max **
rack 1
1 1-3 mr/hr Typical
]
Remove Old Rack 4-6 General Area ld 0.040 - 0.060
)
10 mr/hr Max **
Man Rem / rack 4
1 I
1-3 mr/hr Typical Install New Rack 3-4 General Area ld 0.030 - 0.040 1
10 mr/hr Max **
Man Rem / rack i
10-20 mr/hr Cut up Rack 6
General Area 4d 0.600 Man Rem /
100 mr/hr racks Isoleted Hot Spots 10-20 mr/hr i
Package Rack 6
General Area ld 0.100 Man Rem 100 mr/hr Isolated Hot Spots Estinated exposure based partially upon
- "~
- E" TABLE I past experience.
0.800 - 0.850 y
Localized or short duration.
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