ML20206H321
| ML20206H321 | |
| Person / Time | |
|---|---|
| Site: | Kewaunee, Cooper, 05000000 |
| Issue date: | 09/10/1986 |
| From: | Driscoll J ARGONNE NATIONAL LABORATORY |
| To: | Hayes J NRC |
| Shared Package | |
| ML20206H043 | List: |
| References | |
| CON-FIN-A-2328, TASK-083, TASK-3.D.3.4, TASK-83, TASK-OR, TASK-TM NUDOCS 8704150328 | |
| Download: ML20206H321 (22) | |
Text
.
. ARGONNE
. NATIONAL LABORATORY INTRA-LABORATORY MEMO September 10, 1986 U.S. Nuclear Regulatory Comission Nuclear Reactor Regulatory DSI/RP Mail Stop 416 Washington, DC 20555 Attention: J. Hayes
Subject:
Generic Studies Related to Generic Issue 83 on Control Room Habitability Fin A-2328 Gentlemen:
Enclosed is the Plant Visit Sumary Report for the visit to Kewaunee Nuclear Station on August 11-14, 1986. If you have any questions concerning this report, contact me at (FTS 583-7657).
Very truly yours.
W. UM .
John W. Driscoll Argonne Project Manager JWD:hg cc: D. W. Cissel EBR-II R. Dalton, DOE-CH M. J. Lineberry, SSP 0 R. N. Smith, EBR-II c
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Keeaunee Nuclear Station Page 1 PLANT VISIT
SUMMARY
REPORT
- 1. Plant: Kewaunee Nuclear Station
- 2. Utility: Wisconsin Public Service Corporation
- 3. Location: Kewaunee, Wisconsin
- 4. NRC Region: III
- 5. Visit Date: August 11-14, 1986
- 6. Participants from Argonne National Laboratory: J. W. Ortscoll G. F. Cockerill
- 7. Scope:
The plant visit was made to gather information on control room habitability - Generic Issue 83. As 3 part of the review, the Plant Technical Specifications were reviewed and compared to the ,
safety analysis (including III.D.3.4. submittal and the NRC staff safety evaluation) and plant procedures to determine what opera-tional practices are being employed. System airflow measurements were made to determine the unfiltered air inleakage into the con-trol room envelope and system performance.
- 8. Findings:
8.1 General The Kewaunee Control Room HVAC System is divided into two redundant trains except that common supply ducting for distri-buting air to the control room and common makeup air ducts are shared by the two systems.
Kewaunee Nuclear Station Page 2 All components for both HVAC trains are located in a common equipment room with no physical barriers separating redundant units. The HVAC equipment room is part of the control room 1
envelope. ;
Reg. Guide 1.5.2, " Design, Testing, and Maintenance Criteria for Post Accident ESF Atmosphere Cleanup Systems Air filtra-tion and Adsorption Units of Light Water Cooled Nuclear Power Plants," Item 5.c states, "The use of silicone sealant or any other temporary patching materia.ls on filters, housings, mounting frames, or ducts should not be allowed." Sealant compounds are used on some ductwork joints at Kewaunee.
Manual dampers should be labeled with "open-closed" positions and damper numbers.
- With a few minor revisions, Drawing M 603 could be made to more accurately reflect the actual system configuration.
8.2. Procedures 8.2.1 Procedure SP 25-263 allows fresh air inlet valves to -
be opened during the 10-hour test. The procedure does not address the sequence of switch manipula-tions to obtain fresh air makeup. While taking air flow measurements with the HVAC system in the post-accident recirculation mode of operation, the system was placed in the fresh air makeup mode. The control room return valves ACC-3A and ACC-38 were closed and fresh ai- makeup valve ACC-2 was opened.
However, the fresh air inlet valves ACC-1A and ACC-1B were closed. This allowed the filter fans to take suction on isolated duct sections. When proce-dures allow fresh air makeup'during the post acci-dent recirculation mode of operation, specific steps should be included in the procedure.
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Kewaunee Nuclear Station Page 3 8.2.2 Procedures are ambiguous in'certain instances:
Procedure N-ACC-25 step 4.1.6 refers to cold weather. Step 4.2.1.a. says to set the humidistat at the desired humidity. -
Procedure SP-25-119, step 6.5 does not specify that adsorber cells with the earliest date should be removed for sampling.
8.2.3 Procedure SP-25-119, step 8.5 should specify accep-tance criteria of 6.0 inches H20.
8.2.4 There is no procedure to verify the operability of the control room HVAC equipment from the local control panel.
8.2.5 It is not apparent frcm plant procedures that cpera-tors would manually isolate the control room on a zone SV actuation and annunciation of an auxiliary building high radiation signal as addressed in the '
6/6/83 letter, Giesler to Varga.
8.2.6 Procedure ARM-45 should be revised to include instructions to be followed on loss of radiation monitor R-23.
8.3 Safety Analysis 8.3.1 The Relay Room is protected from fire by a CO2 system which is manually activated. Inlet and
, outlet dampers are closed to isolate the relay room when the C02 system is actuated. Leakage past the isolation valves could allow CO 2 levels to build up 9
Kewaunee Nuclear Station Page 4
. - 1 in the control room. There should be a means pro-vided to monitor C02 levels in the control room when the relay room CO2 system is actuated.
8.3.2 The two fresh air intakes are spaced relatively l close togethet and under certain conditions exhaust l from the auxiliary boiler could be blown toward both intakes at the same time.
8.3.3 The operator cannot determine which fresh air intake !
has the highest airborne concentration without either shifting intakes or taking a survey with portable instruments.
8.3.4 Damper ACC-5 acts as a redundant damper for valves ACC-1A and ACC-18. However, the same signals do not close ACC-5, ACC-1A and ACC-18. If credit is given
('w for redundant isolation dampers, all dampers should isolate from the same isolation signals.
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8.3.5 The toilet and kitchen exhaust. valves should isolate on the same signals that cause closure of the inlet isolation valves.
8.3.6 The III D.3.4 submittal seems to imply that isola-tion valves will be added to isolate each filter train. In the as-built system, there are two isola-tion valves but they are connected in parallel in the return line from the control room. The fresh ;
air makeup valve to the emergency filter train is a single valve and failure of this valve could lead to the filter train fans taking suction on an isolated suction header or supplying outside air to the filter trains.
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Kewaunee Nuclear Station Page 5 8.3.7 In the 4/24/81 submittal to the NRC, unfiltered inleakage was assumed to be 135 cfm. The radiation exposure in the same submittal assumes 55 cfm unfiltered inleakage. The volume of the control room envelope has been enlarged by adding additional space to the control room envelope. The radiation exposure calculations should be recalculated using the proper infiltration term.
8.3.8 If the fresh air makeup is used during an accident, the iodine protection factor (IPF) will be different than when in periods of recirculation only. The fresh air makeup IPF should be used in the radiation exposure calculation for periods of fresh air makeup.
8.3.9 The III D.3.4 submittal indicates that one train of s emergency filtration will be used during an acci-dent. In actual practice, both filter trains are operated at the same time. The utility shou'Id
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conduct an analysis to show that two trains are actually better than one, or revise the procedures to shutdown one train following automatic actuation.
8.3.10 The efficiency used for the charcoal adsorbers in the III D.3.4 submittal is higher than the accep-tance criteria for laboratory testing listed in the Technical Specifications and Procedure SP 25-119. 1 If 90% removal efficiency is the laboratory test criteria, then a new exposure calculation should be used allowing 30% efficiency for methyl iodine removal. Otherwise, the Laboratory test must have an acceptance criteria of 99.3% efficiency (0.7%
penetration) for methyl iodine removal in order to claim 95% efficiency in the dose calculation.
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Kewaunee Nuclear Station Page 6 8.4 Technical Specifications 8.4.1 Technical Specification 4.17.a.2 requires verifica-tion that the control room HVAC system automatically switches to the emergency recirculation mode of
, operation on a high radiation signal at the inlet of the unit. This specification is confusing because the radiation monitor that places the system in the emergency recirculation mode, is located downstream of the air handling units, and is not at the inlet of the unit or system. Outside air makeup seen by the radiation monitor constitutes about 16% of the total air flow past the monitor. The system response could be delayed by the dilution of the potentially contaminated air by the air already in the control room envelope.
8.4.2 The emergency filter trains are operated 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> C_ each month to demonstrate their operability. Since there are no heaters in the filter trains, it is not necessary to operate the trains for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />. A
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shorter time will prove operability.
8.4.3 In Technical Specification 3.12.a. the control room post accident recirculation system should be oper-able in all modes since the basis for not having redundant in line radiation monitors when analyzing for a fuel handling accident was that the recircula-tion system would be operable (see 6/6/85 letter, Giesler to Varga).
8.4.4 In Technical Specification 3.12.b, when one Unit is inoperable, it is not necessary that the operable unit be demonstrated operable on a daily basis for seven days.
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Kewaunee Nuclear Station Page 7 8.4.5 In Technical Specification 3.12.c.1, the acceptance criteria for the in-place 00P and freon tests should be specified as 0.05% penetration for the filter and adsorber and 1% penetration for the system bypass test. Test method ANSI N5 9 should be indicated.
8.4.6 Technical Specification 3.12.c.2 should be revised so that the charcoal test is perfomed at 30*C; 95%
R.H. and should demonstrate a penetration of less than 0.7%. Test method ASTM D3803 should be speci-fled. The laboratory test should be perfomed once per refueling cycle or every 18 months and following painting, fire or chemical release in areas that comunicate with the control room envelope.
8.4.7 The filter fan flow should be specified at 2500 cfm i 10% in Specification 3.12.C.3.
8.4.8 The control room air conditioning system should be included in the Technical Specifications. An ,
acceptable temperature for the control room should be established based on personnel comfort and equip-ment qualification temperatures.
8.4.9 In-place 00P tests should be conducted after fire or chemical release. See Technical Specification l 4.17.b.1.
8.4.10 From the 10/11/85 memo from Truttmann (T/S 3.12 clarification) that if radiation monitor R-23 is inoperable, then monitor R-1, R-5, and R-13 or R-14 must be operable. Therefore, an appropriate action statement should be included in Technical Specifica- l tion 3.12.
Kewaunee Nuclear Station Page 8 8.5 HVAC Flow and CRE Temperature Measurements
.8.5.1 Air temperature was measured in the control room with the plant operating near full power. Data was taken on two different days and with different air handling units (AHU) and rbspective air conditioning units in service. Emergency filter fans (EFF) were also operated in different configurations. In all modes of operation the temperature inside the control panels was higher than the temperature on the occupied side of the control panels. Data set I was taken one day earlier than data sets 2 - 3. The following table summarizes the data:
Temperature Data Data Data Data r Set 1 Set 2 Set 3 s- Equipment AHU-1A. AHU-18 AHU-18 j in Service EFF-1B Occupied Area 77.7'F 75.0*F 74.6*F of Control Room '
Inside Control 78.8'F 77.7'F 76.7*F Panels Control Room 78.1*F 76.0*F 75.4*F Average Differential +1.1*F +2.7'F +2.1*F Temperatures Inside Panels to Control Room NOTE: Data Set I was taken with AHU 1A in normal operation.
Data Set 2 was taken at the start of operation.
Data Set 3 was taken with AHU 1-B in operation with filter train 1-B in operation.
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Kewaunee Nuclear Station Page 9 8.5.2 Flow measurements were taken with the control room HVAC system operating in four modes of operation ;
(see attached data sheets). The following conclu- )
sions are made based on the data taken.
(1) Air handling unit 1A has less capacity than air handling unit 18.
(2) There is 6-12% of rated air flow through isolated charcoal adsorber trains depending on system configuration.
(3) There is significant leakage across isolation dampers ACC-1A, ACC-18, ACC-3A, ACC-38, and ACC-5.
(4) The control room HVAC equipment room is at a slightly negative pressure and the control room is slightly positive or neutral pressure with respect to surrounding areas when the control ,
room HVAC system is operating in emergency modes.
8.6 Outside Air Infiltration The Kewaunee III D.3.4 submittal is confusing as to what value was used in the control room operator dose calculations. The values of 135 cfm and 55 cfm are used in the submittal (see Item 8.3.7). Both of these values may be low since flows as high as 180 cfm were measured across damper ACC-5 when the system was operating in the emergency mode of operation. The 180 cfm does not include leakage into the control room or the HVAC equipment room. Additionally, the control room envelope has been enlarged by an addition to the relay room.
According to the Kewaunee submittal, noble bases may be a significant problem. Values listed in the submittal (47 rem)
I Kewaunee Nuclear Staticn l Page 10 are well below the 75 rem for use of protective clothing.
However, it appeared that a value of 55 cfm unfiltered l inleakage was used in this calculation. We did not find procedures requiring operators to wear protective clothing during an accident.
A complete survey should be taken of the control room envelope to determine what inleakage exists. A new expcsure calcula-tion should be made to determine operator exposure during a DBA.
8.7 LER Evaluation There were no LER's associated with the loss of cooling to the control room envelope. However, there is no technical speci-fications relating to the air conditioning system or to a control room temperature.
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KEWAUNEE NUCLEAR STATION FLOW MEASUREMENT DATA SHEET
. 'P T LOCATION NORMAL DUCT DATA DATA DATA DATA
- FLOW SIZE SET SET SET SET RATES 1 2 3 4 1 UPSTREAM ACC-1A 2500 3.0 2217 2226 165 138 2 UPSTREAM ACC-1B 2500 3.75 101 97 38 38 3 UPSTREAM OF ACC-5 2500 3.0 1287 2475 180 143/204 5 DOWNSTREAM ACC-2 2500 1.77 41 41 99 94/2384 6A FILTER TRAIN 1A FLOW 2500 1.77 361 306 2306 301/103 6B FILTER TRAIN 1B FLOW 2500 1.77 142 147 2637 3009/2777 9 DOWNSTREAM ACC-3B 2500 1.77 181 173 2921 2809/39 12 RECIRC. FLOW TO A/C UNITS 13450 9.58 16909 17005 11151 15635 13 ! UPSTREAM ACC-21 2200 2.53 28 22 28 !68/61 15AIKITCHEN, TOILET AND CAS 950 1.07 1025 1013 1082 931 l ROOM SUPPLY 17 ' MECH. EQUIP. ROOM SUPPLY 1000 1.11 654 1023 1138 1141 l 17A C.R. ENVELOPE TOTAL SUPPLY 15000 7.78 12222 13716 14432 14914 18 , SUPPLY TO RELAY ROOM 6700 5.41 6838 6817 6454 6936 ,
21 lKITCH. AND TOILET EXH. 300 0.49 329 316 253 294 lACC-10 22AlCONTROLROOMEXH. PITOT #3 1.74 433 472 525 489 22B: CONTROL ROOM EXH. PITOT #4 .
,1.74 1436 1493 1691 1702 22CjCONTROL ROOM EXH. PITOT #6 1.74 1789 2219 2542 2600 22D! CONTROL ROOM EXH. PITOT #5 1.74 2142 1643 2098 2107 23 CONTROL ROOM EXH. PITOT #7 6.0 6856 6582 8058 8040 27 1128 1221 1334 l MECH.EQUIP. ROOM EXHAUST 1000 1.4 1243 l 30 UPSTREAM OF ACC-3A 2500 1.77 304 99 2492 51/41 I kSUMMATIONOFC.R. EXHAUST 12656 12409 14914 14938 DATA SET 1 AHU 1A DN, BOTH FILTER FANS OFF, INTAKE ACC-1A OPEN i DATA SET 2 AHU 1B ON, BOTH FILTER FANS OFF, INTAKE ACC-1A OPEN DATA SET 3 AHU 1B ON, BOTH FILTER FANS ON, BOTH INTAKES CLOSED DATA SET 4 AHU 1B ON, FILTER FAN 1B ON, BOTH INTAKES CLOSED NOTE: THE SECOND READINGS IN DATA SET 4 WERE TAKEN WITH FRESH AIR BEING SUPPLIED TO FILTER TRAIN 1B THROUGH ACC-1A & ACC-2
EEy8gNEg_Elgy_DE8@g6EDENIg_p6IS_@Udd86Y I ! l 1 : 1 I
! DATA ! PRIMARY ! FILTER OUT I AHU INLET ! CR SUPPLY I MECH. EQUIP. I I SET : VS I VS ! VS VS I ROOM SUPPLY !
I No. I SECONDARY ! FILTER IN i AHU OUTLET ! CR EXHAUST : VS :
I I ISOLATION I 6A+6B = 1 6A+6B+3+12 : 17A+15A-21 1 MECH. EQUIP. I i 1 1+2 = 3+5 I 9+3O+5 I = 17A+15A 1 = I+27 I ROOM EXHAUST I I : _ _ _ _ !_ _ !__ ! ! 17 = 27 I I : I_ : : I i 1 ! 2217 1287 1 181 1 361 1 1025 I I I : _191 __41 1 361 304 1 142 ! 12222 12656 : 1 4
I I I 142 _31 1 1287 1025 1 _-329 _112@ i i
! : I i 1 ! !
_1 6 _9 0 _9 _1 _2 2 2 _2
! l 2318=1328 : 503=526 l 18699=13247 ! 12918=13784 ! 654=1128 1
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I : : I l l l 8 2 : 2226 2475 ! 173 1 306 1013 i 1
- 97 41 ! 306 99 : 147 l 13716 12409 : !
- : 14Z _41 1 2475 1013 ! _-316 _1221 : :
- : 1 17005 13716 ! ! l
- 2323=2516 ! 453=313 1 19933=14729 : 14413=13630 : 1023=1221 !
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- : i : I 1 3 : 165 180 1 2921 1 2306 l 1082 i -
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! ! 38 99 1 2306 2492 1 2637 ! 14432 14914 l 1 1 : I 2637 99 l 180 1082 ! -253 1243 l l 1 : 1 i 11151 14432 : : !
! l 203=279 I 4943=5413 16274=15514 i 15261=16157 ! 1138=1243 i
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< l i i i I I 4 l 138 143 ! 2809 ! 301 1 931 1 I
! : _3g _94 1 301 51 1 3009 ! 14914 14938 ! !
! ! ! 3999 94 ! 143 931 ! _--294 _1334 I I I I i 15635 14914 I I I I : I I I I I
! ! 176=237 I 3310=2954 1 19087=15845 ! 15551=16272 i 1141=1334 I l 1 i ! ! ! !
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3 I = 22A+22B+22C+22D+23
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Ik' Air temperature was measuraid in the isenNel rose with the plant operating near full power. Data was taken on two different days and i with different air handling unite (ANU) and respective air condition-ing units in service.
in different configurations.
Emergency filter fans (EFF) were also operated In all modes of operation the tempera-ture behind the control panels was higher than the temperature on the assupled side of ther contr'o1 panels. Data set i was taken one day earlier than data sets 2 - 4. The following table sumarizes the datas
- IE!!MB8IWBE_DAT8 DATA DATA DATA DATA REI_1 -_SEI_2 -- ___ BET 3___ ssI_3 EQUIPMENT IN AHU-1A AHU-1B AHU-18 BERVICE AHU-15 EFF-1A EFF-1B EFF-15 occupied AREA 77.7 'F 75.0 *F 74.7 *F 74.6 *F OF CONTROL ROON BEHIND c0NTROL 78.8 'F 77.7 'F Room BAcK PANELS 76.7 'F CONTROL ROOM 78.1 *F 74.0 *F AVERAGE 75.4 *F ~
~ 1 DIFFERENTIAL +1.1 'F +2.7 *F TEFFEMATUREB _ +2.1 'F BACK OF PANELS TO FRONT DF PANELS yL- -
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~46 ANL REPORT i Copper Nuclear Station Page 1 l
l PLANT VISIT
SUMMARY
REPORT 1 Plant: Cooper Nuclear Station ~
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- 2. Utility:
Nebraska Public Power District
- 3. Location: Brownsville, Nebraska 4 NRC Region: IV
- 5. Visit Date: October 2-3. 1985 '
- 6. ' Participants from ArBonne National Laboratory: M. D. Carnes J. W. Driscoll 7 Scope:
The plant visit was made to gather information on control room nabitability - Generic Issue 83. Spectrically the Plant Technical Specifications were reviewed and compared to the safety analysis (including III.D.3.4. submittal and the NRC staff safety evalua-
! tion) and plant procedures to determine what operational practices are being employed. Information relating to loss of cooling in the control room envelope was reviewed to determine the impact of such an event on continued plant operations due to loss of plant instru-mentation. Air flow and temperature measurements were taken in ,
various places throughout the CR HVAC system and envelope.
- 8. Findings:
8.1 General The Control Room (CR) HVAC systen was found to be as described in the USAR and the material provided by the utility (NPPD),
except as follows:
8.1.1 The USAR and III.D.3.4 submittal says that the i emergency bypass is designed for 225 cfm at 2 in. !
static pressure. This conflicts with surveillance procedure 6.3.17.5 which says the system is designed for 341 cfm. In fact, we measured flow in excess of 600 cfm. Test reports by an independent organiza-tion showed flow rates of 341 cfm and 600 cfm mes-
! sured on the same day. The problem is that the emergency supply ran will not see 2 in. of static pressure unless all other fans in the system are shut down. With the normal supply and exhaust fans j running, the differential pressure is a function of l the condition of the' isolation dampers.
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o Copper Nuclear Station
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l 8.1.2 There is no backdraft damper in the toilet and kitchen exhaust as shown on plant drawings.
8.1 3 The USAR and III.D.3.4 submittal do not properly
. describe the events that occur when the emergency i
filtration is placed in service. Emergency supply lineup says that damper AD1021D will open. It should say AD1021-D2 will open and AD1021-D1 will close.
8.1.4 There seemed to be confusion on the part of most
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licensee employees about the source of cooling water for the HVAC chillers. Some said the cooling tower
, on the roof was used in summer. Most seemed con-fused abut the source of power for the HVAC systems.
After lengthy inquiry, we found that turbine equip-ment cooling (TEC) is the primary source of cooling, but it does not have emergency power. The backup cooling source is Plant Service Water (PSW) which f dacs have cmcrgen:y p0wer supply. The feeling was
- that PSW did not have adequate capacity for the HVAC chillers because of a 2-in. cross connect between TEC and PSW which have 3-in. lines.
8.1.5 The III.D.3.4 submittal indicates that dose rates
__ were conservatively calculated based on control roon volume, but the calculations were nade using the total volume space volume ofof 65.300 cuft.ft instead of the free air 33,060 cu 6.2 _ Technical Soecifications The plant is operated and surveillance is performed in accor-dance with the existing Technical Specifications. However, the following changes are recommended to better monitor the performance of the control room HVAC system.
8.2.1 Limit 3.12.A.2.a which requires in place cold DOP testing does not specify a limit for bypass leakage or a testing frequency. Bases 3.12.A indicates 1 there is a limit of less than one percent bypass leakage.
i 8.2.2 Limit 3.12.A.2.c. requires the fans to be tested and shown to operate within 110% of design ficw. The
. design flow rate and fans tested should be stated.
There was a discrepancy in design flow rate of the emergency supply fan as described in the USAR, III.D.3.4 submittal-and the procedure used to test 1 the Tan. The fan actually operates at a higher flow 1 rate than design. This reduces the resident time in the charcoal bed which reduces the lodine removal i
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efficiency. Design flow and operating flow should be verified by the licensee.
8.2 3 Limit 4.12.A.2.a. requires In place cold DOP and halogenated hydrocarbon tests be conducted once per year for standby service and after every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of operation. This is more frequent than recom-mended by Regulatory Guide 1.52.
8.2.4 The III.D.3.4. analysis states that the control room is pressurized during operation of the emergency supply fan. There should be a Technical Specifica-tion for pressurization tests.
The AP gauge the operators used as an indicator of control room AP, was, in fact, measuring the control
- building which is not the control room envelope.
The fact that it indicated a negative pressure in an isolation mode did not seem to concern operators.
8.2.5 There is no list of equipment required for the system to be operable. The supply fans, recirculat-I.
ing fan, dampers, and radiation monitor should be listed. Apparently the emergency filtration system is the only part of the system required to be 0;cra-ble.
8.2.6 Limit 4.12.A.2.d. requires operation of the system for at least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> every month. The basis for this limit is to remove moisture in the charcoal adsorber. Since there is no heater in the filter train, a lesser run time to verify operability should be considered. (See Regulatory Guide 1.52 section 4.d.)
8.2.7 There is no limit as to the naximum temperature in the control room envelope. An assessment should be made of the instrument ratings and a limit estab-11shed where instrumentation will not be adversely affected.
8.2.8 The action statement in Limit 3.12. A.3. allowing the system to be inoperable for seven days generally applies to a system that has redundant components throughout the system. This limit should be reviewed to determine its adequacy for a nonredun-dant system and for exposure rates expected from a design base accident.
8.2.9 Consideration should be given to providing a redundant radiation monitor.
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83 HVAC Flow and CRE Temocrature Measurements 8.3.1 Although the emergency air filtration units were not in operation, field measurements indicated that air was flowing through these ' units at 45-50 percent of the flow which passed through the unit during opera-tion in the emergency supply mode.
8.3.2 Air temperatures behind the control room instrument panels were slightly above control room ambient generally about +3*F and in no case more than 7*F above normal ambient.
833 The cable room was negative with respect to the computer room and control building. There was significant air movement into the cable room from these areas as Indicated by smoke tests with the system in the emergency supply mode of operation.
This allows unfiltered air to be supplied to the control room via the ' cable room.
8.3.4 It was reported that during halon system testing in the computer room, halon leaked into the cable room.
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8.3.5 Air flow velocities through the charecal adsorber were about 200% of design when the system was oper-ating in the emergency mode. ,
8.4 Outside Air Inr11tration A review of the III.D.3.t. submittal is very confusing as to what the design inleakage is. One could assume design inleak-age of 10-450 cfm from the submittal. We were unable to measure the inr11tration rate but the following observations were made.
8.k.1 Access to the control room was through a single door which communicated with the control building (not part of the control room envelope). This access places you in a hallway (part of the control room envelope) outside the control room. The hallway is in the same ventilation zone as the control room. A locked door provided access to the control room from the hallway.
8.4.2 The control room hallway had access to the computer room.
8.4.3 The doors from the control building to the control
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room hallway and from the control room hallway to I the computer room were provided with seals to mini-
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mi:e air leakage across the control room envelope
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Copper Nuclear Station Page 5 h.
boundary. These were the only doors that were provided with seals to minimize air leakage across the control room envelope boundary.
8.4.4 Access to the cable room was through a locked door ln the computer room, down a stairway, and through another door. There is also an emergency ex'It door from the cable room to the control building.
8.4.5 The control room, control room hallway, and cable room are in the control room envelope. These areas are in the control building. Most of the control building including the computer room is outside the control room envelope.
8.4.6 There was an alarmed emergency exit from the cable room to the control building.
8 0.7 Smoke tests showed pressure in the control room hallway was positive with respect to the control building and to the computer room. The CR-HVAC system was in the emergency supply mode of operation
! when the tests were made.
8.4.8 Air flow velocities through the main supply 1:cla-tion valve when isolated was about 20% of the air flow measured in normal operation. This was about five times the air flow through the emergency supply ~
filtration unit.
8.4.9 Air velocity measurements on the intake stack and exhaust stack during emergency supply mode of opera-tions showed that four times more air was being exhausted from the control room envelope than was being supplied. This was apparently because of exhaust damper leakage and the inleakage of air across the control room envelope boundary into the cable room. This inleakage allows unfiltered air to enter the control room envelope.
8.5 LER Evaluation !
Since there is no Technical Specification limit on operability of equipment or high temperature, LER's have not been written l concerning loss of cooling to the control room envelope. )
Discussion with plant personnel did reveal that there has been !
several times that cooling has been lost to the control room HVAC system.
l maintenance work One such event was identified by searching for
! ponents. requests that was issued on associated com-All cooling water was secured to the refrigeration
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l
.Capptr Nucletr StEtion Page 6 q
unit for a period of about 26 hours3.009259e-4 days <br />0.00722 hours <br />4.298942e-5 weeks <br />9.893e-6 months <br />. The plant was in the refueling mode of operation.
There were no log entries concerning the event (certain logs '
l were not found for the dates involved) other than the issuance of the work request and powering dosn of the plant computer.
Subsequent discussions with plant personnel revealed that control panel covers were removed and portable fans were positioned to cool instrumentation. The maximum temperature reached was 97*F but it was uncertain exactly where the tem-perature was read.
tion.
There was no apparent loss of instrumenta-H h
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No.614 431 0858 Mar 23.87 11:43 P.01/02 SULTING
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! r NUCLE 9R40SSULTING No.614 431 0858 Mar 23.87 11:47 P.02/02 4
W Nudear Consulting E Services,inc.
O p.o sox mot.cauusus om one N .
23 March 1987 U.S. Nuclear Regulatory Coaunission Attn: Mr. Conrad McCracken Acting Chief Plant Systems Branch Division of PWR Licensing - A
Dear Mr. McCracken:
I an one of the lectuers at the Harvard Seminar on N.P. Control Room Habitability Engineering put on by Dr. Moeller.
To assure that I am discussing relevant subjects it vould be helpful if I could have access to some of the control room evaluation reports gefiersted by the NRC contractor (ANL).
^
The information you could supply would be treated as you request. I need it for backgrouod data only.
Thank you in advance.
Regards, I
t Kovach JIIrlp
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