ML20113G441
| ML20113G441 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 01/09/1985 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 9605N, NUDOCS 8501240357 | |
| Download: ML20113G441 (14) | |
Text
f'M Commonwealth Edison e
(
) One First Natiorul Pirra. Chictgo !!hnois gC j Address Reply to: Post Office Box 767 Chicago, lilinois 60690 x
j January 9, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Braidwood Generating Station Units 1 and 2 Volume Reduction System NRC-Docket Nos. 50-454/455 and 50-456/457 Reference (a):
December 14, 1984 letter from B. J.
Youngblood to D. L. Farrar.
Dear Mr. Denton:
This letter provides responses to NRC questions regarding the Byron /Braidwood volume reduction systems.
This information will be incorporated into the FSAR at the earliest opportunity.
Enclosed are the responses to questions 321.101, 321.102, and 321.105 thru 321.113 which were sent to us in reference (a).
The responses to questions 321.100, 321.103, and 321.104 will be provided within a week.
Please direct any further questions regarding these matters to this office.
One signed original and fifteen copies of this letter and the enclosures are provided for your review.
Very truly yours, hhef4" T. R. Tramm Nuclear Licensing Administrator 1m Attachment
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B501240357 850109 7
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9605N PDR ADOCK 05000454 P
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- f Question 321.101
-The response to Question 321.75 states that the dry waste processor has a high oxygen alarm.
However, such an alarm is not shown on Drawing M-48, Sheet 36.
Verify that the alarm is, in fact, present.
Response
AECC's September 17 letter to the NRC added a high oxygen alarm'to the oxygen monitor on the Dry Waste Processor ex-haust in Topical Report AECC-2-P(NP).
However, the Byron VR System does not have a high oxygen alarm at the Dry Waste Processor outlet.
There is a low oxygen alarm associated with AERSAL 75c.
AERSAL 75c provides information to the operator during Dry Waste Processor operation.
If oxygen level is low, this indicates that rate of feed of either the DAW or oil is too high, and that combustion could be incom-plete.
Operating the Dry Waste Processor under high oxygen conditions does not impair the system because complete com-bustion still occurs.
A high oxygen alarm is a convenience since it tells the operator that the waste feed rate is too low for efficient operation but it is not necessary because the oxygen level recorder AERSAL 75c provides oxygen level J
information to the operator on a continual basis.
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Question 321.102 The response to Question 321.75 indicates that the operator can adjust the trash feed rate using controllers SCl26 or SC127.
How is the feed rate of contaminated oil adjusted to control the process when oil is incinerated with and without trash?
Response
As is noted in the response to Question 321.98b, the speed of'the contaminated oil pump can be adjusted via a manual speed controller to maintain the dry waste processor heat release rate at the design value.
The response to Question 321.75 has been modified to indicate the speed control for the contaminated oil pump.
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Ouestion 321.105
Response
"b" to Question 321.79 is not adequate justifica-tion for not having a high level alarm for the contaminated oil leak.
Provide additional justification for omitting the alarm.
Response
As is noted in the response to Question 321.85, the contamin-ated oil' tank currently does not have a high level alarm; however, the tank does have a high level switch.
In the event of high level, this switch causes the tank's inlet valve to close and it also stops the feed pumps that deliver oil to the contaminated oil tank.
The position of the valve is shown on the VR System local control panel; therefore, the operator would know that this valve was closed.
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,s Question 321.106 Verify that the HEPA filters and charcoal absorbers will be tested to the frequency noted in Regulatory Guide 1.140, as discussed in response "d" to Question 321.83.
In a September 17, 1984 letter to Mr. Cecil Thomas (NRC), Aerojet Energy Conversion Company (AECC) agreed to add instrumen-tation to the filters and absorbers in the AECC-2-P-VR system design.
Either provide such instrumentation in your s
system, or provide a justification for its omission.
Response
The HEPA filters and charcoal adsorbers will be tested to the frequency noted-in Regulatory Guide 1.140, or more fre-quently in-the event that filter or adsorber changeout is required at more frequent intervals.
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Regarding additional instrumentation,-
(1)
AP indicators across the'HEPA filters.
No' indicator
'is currently provided; however, high AP' alarms are provided.
The filters are anticipated to last approximately 4 to 6 months, or longer,fbefore approaching the maximum dust-loading capability ' of the filter.
The differential pressure across' the first-stage HEPA filter and the differential-pressure.across the combined charcoal adsorber/second-stage
~
HEPA filter are connected to high differential pressure f
alarms at~the VR System main control panel.
The high pressure alarms are set at 75% of the maximum allowable differential
. pressure so that ample time and reserve-filter capacity is C
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Response to Question 321.106 (Cont.)
available to allow an orderly changeover to the second filter bank.
Thus, the addition of the AP indicators does not re-sult in an increase in the safe operation of the system.
Con-versely, the exclusion of the AP indicators does not result in any additional releases from the system.
(2)
Flow indication, high flow alarm, and low flow alarm either upstream or downstream of'the final filter assembly.
Although the flow rate to the filters is not directly measured, the' flow rate to the total system is accurately measured, con-trolled, and alarmed.
The major air flows are the fluidizing air flow to the dryer-and the dry waste processor.
These flows are indicated, recorded, and alarmed (high and low) at the VR System main control panel..Two other major flows are the transfer air to convey trash to the dry waste processor and the transfer air to convey dryer bed material to the cyclone.
These flows are also-indicated and controlled.
The remaining gas flows are instrument air and nozzle atomization air, and are indicated and adjusted on a twice per shift basis.
In this way the gas flow to the filter assembly is indirectly monitored and controlled.
In addition, the system, acts much like a flow res triction, and as the gas flows are increased and decreased, the system pressure varies-accordingly.
This pressure is
. recorded and alarmed (high and low) to identify upset conditions.
Thus, j e is felt that the addition of flow indication, high
/
flow rtarm, and low flow alarm either upstream or downstream
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Response to Question 321.'106 (Cont.)
of the final filter assembly does not result in an increase in the safe operation of the system.
Conversely, the exclu-sion of this instrumentation does not result in any additional releases from the system.
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Question 321.107 The response to Question 321. 87 indicates that the secondary scrubber performance is monitored.through a AP indicator, PDI 310.
However, Sheet 34 of Drawing M-48 does not show PDI-310.
Does the Byron VR system contain such an indicator?
If not, how can the VR system operator monitor. performance of the secondary scrubber?
Response
The Byron VR' system does contain a AP indicator to monitor the performance of the secondary scrubber.
The designation used by the VR system vendor for this indicator is PDI 310.
The.
designation-used for this AP indicator on Sheet 34 of Drawing M-48.is OPDI VR 128.
The response to Question 321.87 has
- been modified to indicate the designation given on Drawing M-48, Sheet 34.
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Question 321.108 The response to Question 321.90 indicates that the system would safety shut down if the inlet air filters were plugged.
However, since there are parallel paths that could divert flow around the filters, it is not obvious that the system would shut down.
Provide additional discussion of the con-sequences of plugged inlet filters or pr' ovide AP instrumenta-tion for the filters (OVR03M and OVR02M).
Response
OVRO3M and OVRO2M are the inlet air filters on the C-2 and C-3 air blowers.
Neither filter is equipped with a AP indi-cator.
Both of these filters are expected to operate about 3000 hours0.0347 days <br />0.833 hours <br />0.00496 weeks <br />0.00114 months <br /> before plugging.
It is planned that these filters be washed monthly and changed out annually during the VR sys-tem's annual maintenance.
In the worst case, if either filter plugged, the system would
. safely shut down on low pressure and alarm on low gas flows.
The plugged filter could then be changed and the -system re-started.
It takes about 1/2 hour to service the C-2 and C-3 blower inlet filters.
Thus, it is felt that the addition of AP instrumentation does not result in any increase in the safe operation of the system.
Conversely, the exclusion of this instrumentation does not result in any additional releases from the system.
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-Question 321.109 The response to Question 321.92 states that no instrument has been provided on the trash shredder filter to indicate that'it is-plugged because this filter can-be visually in-spected.
However, visual inspection will not indicate that a filter is plugged.
Either provide instrumentation for such a determination or provide additional justification for its omission.
Response
- The inlet to the trash shredder is fitted with an inlet air screen, which consists of several overlapping strips of plastic material.
During trash feeding to the shredder, an air. flow -rate of about 2400 SCFM exists - through the shredder inlet port and out through the shredder filter..
This air flow causes a continual movement of the inlet air screen.
As the pressure drop.across the shredder filter increases, this air flow rate, of course, decreases.
Correspondingly, the-air screen movement also decreases.-
At approximately 600 SCFM air flow rate, the air screen movement is no longer visible t
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, to.the operator. 'This is a clear indication to the operator I -
that the : filter is partially ~ plugged and must be replaced.
'This filter can be replaced quickly.
-It should be.noted that 600 SCFM is adequate'for shredder ventilation.
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. Question 321.110 The response to Question 321.98 states that a flow indicator on ' the exhaust of the booster. blower is not required since the air' entering the VR system is measured.
However, this does not provide assurance that the booster blower is working.
Therefore, provide a flow indicator on the exhaust of the
' booster blower or demonstrate that it is'not needed.
Response
Part'of the response to Question ~ 321.106 dealt with the possi-ble-addition of a flow indicator, a high flow alarm, and a low.
flow alarm, either upstream or downstream of the final filter assembly.
The response indicated that the major flow rates are indicated, recorded, and alarmed upstream of the filter package, and no further instrumentation was required.
The booster. blower is just downstream of the final filter assembly.
Knowledge of actual flow rate through the booster blower is not essential to system. operation, since flow rate information is available upstream (at inlet to dryer and dry waste processor).
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If the booster-blower fails,L the VR system would automatically-shut down due to.a high pressure alarm.
'Thus, the addition of a flow indicating device to the booster j
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b1ower does not result in an increase. in : the safe operation of the system.
Conversely, the exclusion of'this instrumenta-'
tion does not r'esult in any additional releases from the system.
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m Question 321.111
Response
"f" to Question 321.98 states that filter OVRO 8F has a AP indicator, but does not have a AP alarm.
Provide a procedure that will assure the operator knows that the filter has plugged to provide the alarm.
Response
This filter is equipped with a AP indicato<..
This parameter will be logged twice per shift when' the VR system is operating.
Since this filter is designed to operate about 3000 hours0.0347 days <br />0.833 hours <br />0.00496 weeks <br />0.00114 months <br /> before plugging, the data gathered each shift will alert the operator to the filter's condition.
Replacement of the filter can-be accomplished before the filter' is completely plugged.
A plugged filter would result in system shutdown due to low pressure at the dryer windbox.
Thus, sufficient instrumentation already exists to provide the operator with the status of the filter.
The addition of a. AP alarm does not result in an increase in 'the safe opera-tion of the system.
Conversely, the exclusion of this instru-mentation does not result in any additional releases from the system.
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Question 321.112
..How do -you ensure that the bed storage and transfer hoppers
-are not overfilled when transferring from one hopper to another for the purpose of sending the material to the surge hopper?
Response
Material is never transferred from one hopper to another for
-the purpose of sending material to the Surge Hopper.
The trans-fer path for material ~ from the Fluidized Bed Dryer and the Dry Wastb Processor is as follows (refer to Figure 11.4-7, Sheets 3 and 4):
Fluidized Bed Dryer OVROlD:
Material is transferred from the Fluidized Bed Dryer via the Acceleration Chamber OVR55M to the Gas / Solids Separator OVRO2P to the Surge Hopper'OVR51M.
-Dry Waste Processor OVRO35:
Material-is transferred from the Dry Waste Processor to the Bed Storage and Transfer Hopper OVR06T, then to the Fluidized Bed Dryer, then via the Acceler--
allor Chamber to the Gas / Solids Separator to~ the Surge Hopper.:
This procedure precludes overfilling of tdua bed storage' and transfer _ hoppers since the only inventory of material that is ever transferred to a hopper is the' normal working. inventory
-contained in.the corresponding process vessel, i.e.,
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fluidized bed dryer contents can be transferred to and from u
the OVRO7T Bed Storage.and Transfer Hopper only. LThe Dry 1
Waste Processor contents can be transferred to and from the
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OVR06T Bed Storage and Transfer HopperL only.
The hoppers have/a. capacity 50%. greater than the working inventory of the corresponding process vessel.
LAlso, see the response to Question 321.98g.-
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Question 321.113 If the scrubber /preconcentrator vessel ruptures or one of the discharge pipes from the scrubber /preconcentrator ruptures, where does the liquid go?
At what elevations would it be spilled over.and would it be collected above or below grade?
Response
If the scrubber /preconcentrator vessel ruptures or one of the dischargelpipes from the scrubber /preconcentrator: ruptures, the liquid 'is initially deposited on1the floor below the scrubber /preconcentrator and collected by the floor drains.
From there, it is transferred back to the liquid radwaste system to be reprocessed.
The elevation of the floor under the-scrubber /prc' concentrator is 398'0" and the grade elevation.
is 400'9"; therefore, the liquic is collected below grade.
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