ML19270H775
| ML19270H775 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/10/1979 |
| From: | Jay Collins NRC - NRC THREE MILE ISLAND TASK FORCE |
| To: | Bangart R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8001030471 | |
| Download: ML19270H775 (6) | |
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DISTRIBUTION:
SEP r/f December 10, 1979 PSB r/f TMI r/f NRR r/f CENTRALFILE!
Docket No.: 50-259 NRC PDR LOCAL PDR MEMORANDU'i FOR:' R. L. Bangart, Acting Chief JTCOLLINS Effluent Treatment Branch Division of Safety Evaluation R. W. Reid, Chief b
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Operating Reactors Branch, No. (t'
[h )hmer h c.I" Division of Operating Reactors a
FROM:
J. T. Collins, Deputy Director TMI Support
SUBJECT:
AMENDMENT TO OPERATING LICENSE FOR TMI UNIT 1, ON AIR TREATEENT SYSTEMS TECHNICAL SPECIFICATIONS en the past several raonths, I have indicated that it is non-productive at this time to 3o forwara with the proposed license amendaent for TMI-l in l
view of the fact that the licensee is a.aking changes to the Auxiliary /
Fuel Handling Building 6xnaust Ventilatiun System to meet the conditions set forth in Criteria f4 of the Comission's Order and Notice of Hearing dated August 9, 1979, for THI-l restart.
This criteria requires thG cocplete separation and/or isolation of TMI-l and TMI-2 radioactive waste systems, specifically, the radioactive liquid transfer lines, ventilation systems, and sampling lines. To meet this criteria, Met-Ed has proposed in Amendment 7 to the TMI-l Restart Report, modifications to the existing TMI-l Auxiliary / Fuel Handling Building Ventilation Systera and the installation of a new EFS system for the TMI-1 fuel Handling Suilding (See Enclosure LJ. These proposed changes, if approved by the staff, will alter the operation of the existing systera and will require a change in the existing Tech Specs for TMI-1.
In view of this, I m again requesting that no action be taken on this amendment until the proposed codification has been approved and the method of operation establisned.
I have discussed this with Roy Harding, Met-Ed and he concurs with this approach.
a00R BHM J. T. Collins i
Deputy Director TMI Support i676 00
Enclosure:
As Stated bec:
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NRC Form 318A M 79: NRCM CN)40 e.........-..,me.-...
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QUESTION 52.
Provide detailed design features of Fuel Handling Building environmental barrier.
RESPONSE
The following describes the TMI 1 and 2 Fuel Handling and Auxiliary Building supply and exhaust systems.
The potential leakage paths between buildings or systems and the modifications designed to isolate the unit I refueling floor from the unit 1 Auxiliary Building and from the Control Access Building are discussed.
These modifications include ventilation system changes and certain building layout changes. The major ventilation considerations are as follows:
A.
The supply and exhaust systems for unit 1 are separate from those of unit 2.
However, the unit I refueling floor air communicates directly with the unit 2 refueling floor air.
B.
The supply systems of the Auxiliary and Fuel Handling Building (FHB) of IMI-l are separate from each other.
Both systems supply air to the building areas through duct distribution systems using outside air drawn from the air intake tunnel.
Both supply fans are located in a common tunnel in close proximity to each other.
None of the supply ducts of the Auxiliary Building are located in the FHB area.
Thus, there is no potential for air leakage between Auxili-ary and FH Building through outlets or through leaka in the Auxiliary Building supply duct system.
The supply duct main f or the FHB serves the general area at elevation 305'-0", the Spent Fuel Cooling Pump area at elevation 305'-0" and then serves the refueling floor at elevation 348'-0".
The FHB refueling floor could communicate with the Auxiliary Building through the supply duct system because the general area and the Spent Fuel Cooling Pump area are open to the Auxiliary Building through en open doorway at elevation 305'-0".
C.
The exhaust systems for Auxiliary and FH buildings of TMI-1 are separate in the specific buildings they serve but the FHB exhaust main becomes common with the auxiliary building exhaust main af ter leaving the FHB.
The common main is directed to multiple filter plenums and f ans that exhaust the mixed air.
The building modifications designed to isolate the TMI-1 refueling floor from the TMI-1 Auxiliary Building and from the Control Access Building include (See Drawing 010-006 attached):
A.
Two pairs of double doors at elevation 281'-0".
B.
An enclosed passage at elevation 305'-0" with two main doors and one pair of equipment doors.
Am. 7
C.
A wall at the east end of the truck bay at elevation 305'-0".
The wall should be removable f or large equipment access to the machine shop.
D.
A security fence at the west end of the dock adjacent to the new enclosure at elevation 305'-0".
E.
The stair tower between elevations 299 '-2k" & 211'-0" will be modified.
F.
Pressure tight doors for the new fuel storage room at elevation 329'-0".
G.
Pressure tight doors for the stair tower at elevation 331'-0".
H.
An enclosure at elevator entrance with a pressure sealed door.
I.
An enclosure fc-the ventilation duct chase in the northwest corner of the refueling floor with one pair of pressure tight doors.
The TMI-l ventilation system modifications designed to prevent the leakage paths are given below:
A.
Air leakage from the FHB through the supply duct, to the de-energized FHB supply fan to the Auxiliary Building are stopped by adding a leak tight damper in the discharge of the FHB supply fan.
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B.
Air leakage from the FHB through the supply duct, and the 48" x 24" branch duct, to the FHB general area at elevation 305'-0", and then to the Auxiliary Building will be stopped by blanking off this duct and providing an equivalent opening in the FHB supply duct. This would discharge the required 8000 cfm on the south side of the elevator shaf t and this air would rise through the open stairwell to be exhausted at the refueling floor.
C.
Air leakage following the same path as ites B above but through a 12 x 12 branch duct in the spent fuel pool cooler area at elevation 305'-0" will be stopped by blanking of f this duct.
The 1000 cfm exhaust required by this area will then be supplied from the Auxili-ary Building through the wall opening at elevation 305'-0".
D.
Air leakage from the Auxiliary Building to the fuel building will be stopped by adding a leak tight damper in the exhaust duct main as it leaves the FHB but upstream of the connection with the Auxiliary Building main (60 x 50, elev. 348).
E.
The leak tight dampers added to the FHB supply and exhaust ducts and the supply fan will function as follows:
1676 102 Am. 7
1.
Automatically close on detection of differential pressure in the FHB with respect to the Auxiliary Building. g 2.
Automatically close on detection of high radiatiod on the
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refueling floor or in the FHB return air duct.
3.
Open or e ose on manual command from control stations in the FHB and in the Control Room. The manual station would I
"over-ride" the above automatic signals.
J The post modification system response following various assumed accidents [
and events is given below:
ACCIDENT / EVENT
RESPONSE
1.
Differential A differential between these two areas could develop pressure develops as a result of the loss of either the fuel building between the Auxili-or the auxiliary building supply fans or failure in ary and FHB.
the closed position of the dampers in the exhaust mains from either of the buildings.
Leakage t,etween the buildings in aither direction would be stopped by adding the building and the ventilation system codifications.
2 2.
High radiatio _n "
The ventilation system modification would automatically in the FHB or in isolate the TMI-l FHB from the Auxiliary Building.
the FHB exhaust Supply air flow and exhaust air dampers would initially duct.
close and the FHB supply fan would stop.
- However, subsequently, these dampers could be opened and air flow through the fuel building could be re-established at the discretion of the plant operator. Also, the operator could limit the exhaust flow by opening only the exhaust damper. Operation of the Auxiliary Building supply and exhaust system would continue during the isolation phase.
1 3.
High radiation __~
High radiation would be detected and alarmed locally and in TMI-l Auxiliary in the control room by area monitors and by a monitor in Building.
the exhaust duct from this area. The supply and exhaust system could continue operation to reduce the radiation level.
If necessary, the refueling floor could be manu-ally isolated.
4.
High radiation The same response as noted in item 3 above would occur.
in IMI-2 refueling floor.
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PAGE 2 0F RESP 0h'SE TO QUESTION 52. SUPPt.ENDT 'I'; TART 2' -
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f In' addition to the ::odifiestions described above, a ventilation systen to citigate the consequences of a postulated fuel handling. sccident. In the i
l FHB will be installed. This new systen will neat the require =ents of Regulatory Guide 1.52, Revision 2.
This system vill be' installed prior 1;
.; r to the first refueling following restart.
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