ML20245B359
| ML20245B359 | |
| Person / Time | |
|---|---|
| Site: | Cooper, Fort Calhoun, 05000000 |
| Issue date: | 06/09/1987 |
| From: | Long W Office of Nuclear Reactor Regulation |
| To: | Jocelyn Craig Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20236F478 | List: |
| References | |
| TASK-3.D.3.4, TASK-TM TAC-60957, NUDOCS 8706120173 | |
| Download: ML20245B359 (3) | |
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ATTACHMENT I p
UNITED STATES l
'g NUCLEAR REGULATORY COMMISSION
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June 9,1987 MEMORANDUM FOR:
John W. Craig, Chief Plant Systees Branch Division of Engineering and System Technol William Long, Project Manager FROM:
Project Directorate - IV Division of Reactor Projects - III, IV, V and Special Projects COOPER NUCLEAR STATION - CONTROL ROOM HABITABILITY
SUBJECT:
TAC NO. 60957, STATUS l
BACKGROUND the licensee responded to TMI lten III.D.3.4 with a Stone and On 12/30/80, Webster " Control Room Habitability Study."
On 2/12/82, AEB completed its review of the study and sent DL an SER stating l
The SER was that the review was completed and there are no open itess.
fo marded to the licensee on 2/24/82.
I 3/4, 1985, the staff, with the assistance of Argonne Laboratory, i
DSI forwarded a copy l
r.I.
On October performed a control room habitability survey at Cooper.The memorandun stated that, p 10/29/85.
The NRR of the report to R-IV on certain discrepancies would be resolved by R-IV and others by NRR.
itees involved inadequacy of Technical Specifications and discrepancies between measured volume, flow, and leakage rates and the design values indicated in the Stone & Webster study.
5 R-IV followed-up on their items with a letter to the licensee f
On 12/13/85, The licensee responded to R-IV on I/30/86.
The requesting information. licensee provided a plan of action for review and upgra t
vent system.
On 3/5/86, the AD for BWRs fo Narded a copy of the Argonne report to BWD2 reconsending that (1) the III.D.3.4 issue be reopened on the basis of the I
The 3/5/87 memorandum also Argonne findings, and (2) a new TAC be opened.
(Theproject requested that the Arponne report be sent to the licensee.
manager has held off from officially sending the Argonne report to the licensee until internal comments are resolved).
On 3/14/86, TAC No. 60957 " COOPER STATION CONTROL ROOM HABITABILITY" was A
initiated.
tad comments The Cooper Project Manager reviewed the Argonne report andThe comments were on each finding and recommendation.
reviewers Mike Lamastra and Angela Chu on 8/13/86.
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, June 9,1987 1
On 9/18/86, the Project Manager received (informal transmittal), a " Summary of Technical Concerns Identified in the Argonne Plant Visit Report" froe The transmittal requested that it be forwarded to the licensee Mike Lamastra.
and a meeting be arranged.
x s indicating The Project Manager received a call (date not recorded) from J.~
only has that there is a problem in that the Cooper Control Roon Vent one-valve isolation from the environs and thus doesn't meet single-failure (This concern was not identified in the Argonne report or in the criteria.
" Summary of Technical Concerns").
the licensee sent a letter to R-IV describing corrective actions On 12/31/86, The letter described and plans for future actions regarding the R-IV items.
modifications being made during the 1986 outage, and plans for a performance Results of evaluation and determination of any needs for future modifications.
this evaluation are to be sent to NRC upon completion and prior to the next (1988) outage.
During a January 1987 visit to the site, W. Long received an informal response to Lamast:u's Technical Concerns.
Upon return to Bethesda, the licensee's The licensee's response states that the response was given to Mr. Lamastra. evaluation discussed immediately above)
STATUS:
The staff is awaiting the licensee's evaluation.
&'I ACTION REQUEST:
The irm raised by J. Hayes needs to be translated into a staff position If the present valve configuration (1) and br u;ht to the licensee's attention.
1s urac.ptable, Plant Systems should provide a draft position letter.
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?l PD J11 combine it with the Argonne concerns for formal transmittal to 4*
the licensee.
E Plant systems should review the licensee's January response to the NRC (2) technical concerns and inform PD-IV whether it resolves any of the Argonne items.
4/
William Long, Project Manager Project Directorate - IV Division of Ret.ctor Projects - III, IV, V and Special Projects DISTRIBUTION Docket File PD4 Reading I
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Blong PD4 Plant File A!hu MLamastra JHayes JGagliardo D0ubois RPerfetti PM/LA PD4/PM PD4/D[N PMoonan tR.agg:sr JCalvo 6/ /87 6/ y/87 6/7/87
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ATTACHiiENT 2
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UNITED STATES NUCLEAR REGULATORY COMMISSION
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2 Docket No. 50-285 Mr. R.L. Andrews Division Manager - Nuclear Production Omaha Public >ower District 1623 Harney Street i
Omaha, Nebraska 68102 SURVEY OF FORT CALHOUN STATION CONTROL ROOM VENTILATION
SUBJECT:
During the period of October 27-30, 1986 a survey was conducted at the Fort The survey was performed by John Driscoli and Calhoun Nuclear Power Plant.
The Roger Evans, Argonne National Laboratory ((ANL), and Jack Hayes, NRC.1 purpose of the survey was to evaluate: ventilation system and its ability to m habitable and (2) the adequacy of the plant's technical specifications and procedures to demonstrate system operability and system capability consistent with the assumptions made in the plant's TMI Action Iten III.D.3.4, " Control Room Habitability" analysis and the NRC staff's associated safety evaluation.
sC The survey team gathered flow rate data in various portions of the control room ventilation system with the system operating in its nomal mode of operation.
In addition, data was also gathered with the ventilation system operating in its emergency radiological and toxic gas operating modes. The survey team's ifica-observations covered systes operation and des.i n plant technical s f
tionsandprocedures,andtheTMIActionItasf!I.D.3.4 analysis.
h observa-tions were discussed with Omaha Public Power District personnel during the exit
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meeting; however, detailed results of the flow analysis were not avai able at that time.
I The survey team's observations are listed below:
General Observations Data gathered by the survey team showed that portions of the control room (1) envelope were at a negative pressure when the ventilation systems were operating in the emergency mode of operation associated witi a radiological This is contrary to plant technical specifications and the challenge.
design basis for the facility which require it to be positive.
There appears to be a significant amount of leakage fres
- air handling (2) le amount units such that under certain operating conditions a c of unfiltered inleakage into the air handling unit any since you assumed no unfiltered inleakage into the envelope in your (sed III.D.3.4 analysis of September 23, 1985, the inleakage associated with these units appears contrary to your assumption.
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.. May 28,1987 envelope Thereis a considerable amount of inleaka e into the control s operating in i rgency (3) when the control room ventilation systemIn the case of a radiological chall inleakage modes of operation.
740-1100 cfm of flow h the measured by the survey team includes outside air normal makeup damper; 500 cf= of inleakage into the air cfm tr the return duct work from the handling unit VF-468, and 2000-3800For the toxic gas challenge, inleakage 600-1500 cfm through the normal and emergency outside air intakes, 4700 cfm into control room.
the air handling units when VF-468 is operating, 3900 cfm into the return ductwork from tw control roca when W-468 is operatingIng.d 2100 cfa in an the control room supply ductworks when W-46A 1's operat Because of these large inleakage rates and the fact that portions of the control roca are at a negative pressere during the radiological mode of opera-tion, you should perform a reanalysis to determine whether the conclusions previously presented in your TMI Action Plan Itea 111.D.3.4 analysis a valid.
Observations involving plant operation includ_e:
The members of the plant staff res>onsible for the ventilation system need to be familiar with the licensing > asis for the plant so thtt they (1) understand the impact of changes to design conditions involving the
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control room ventilation equipment and its envelope.
The control room envelope should be at a positive pressure of 1/8 inch W.G. with respect to all adjacent areas under the emergency mode of (2)
Areas where improvements can be operation for a radiological incident.made include the sealing of doo i
of leaks in the air handling units.
Additional attention should be given to maintaining the air handling k
(3) units.
Significant flow occurs between the idle control room air handling unit and the operating units. There seems to be recirculation through dampers (4) which do not isolate.
Control room temperature is the most evenly distributed of.any control (5) room the survey team has seen to date.
Observations involvina system desion include:
failure The control room ventilation system is susceptible te si
, the toilet (1)
(e.g., normal intake diaper 860C, emergency intake r
exhaust damper, and the control room exhaust damper The control room envelope pressure should be measured hel ive to all (2) adjacentareas,notjusttoatmosphere.
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4 May 28,1987 3,,
The location of the control room ventilation system equipment say make it (3) susceptible to a high energy line break and to steam intrusion into the control room.
l The location of the diesel generator exhaust is at the same elevation as (4) into the control the control room intake.
A concern is the drawing of CO2 l
room envelope through the control room emergency intake The licensee should verify whether the capacity of the HEPA filter (5) utilized in the control room emergency ventilation system is 1000 cfm or Flow appears to be outside the technical specification limit of 1200 cfs.
design 110%.
The design value should be noted in the technical specification.
The toilet exhaust damper seals the tightest of any the staff has seen to (5) date.
l The modification to one of the auxiliary building fans to allow it to (7) operate at a variable speed should be considered for two fans so that redundancy is provided.
With such a change, credit could be taken for the l
ECCS charcoal adsorber units in the LOCA dose analysis and the control room operator dose analysis.
.i The adequacy of system cooling capability is questionable t?cause both air I~~
(8) handling units must be operated during t5e summer to maintain the control room comfortable.
Observations on technical specifications included:
The present technical specifications do not track with the licensee's (1) assumptions. utilized in their analyses and accepted by the NRC staff in Technical specifications should reflect licensing basis their SER.
Proposed changes were discussed with the OPPD staff and assumptions.
include acceptance criteria of the laboratory test of charcoal and the acceptance criteria to which positive pressure is to be maintained in the control room envelope.
The equipment qualification temperature should be measured in cabinets and (2) not on the control room wall or in the operator station area.
Other comments were provided to the OPPD staff and included acceptance (3) critaria for ia-place tests of HEPA filters and charcoal adsorbers, control room equipment and instrumentation qualification temperature.
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May 28,1987 4
1 Observations ~iin procedures include:
(1) Procedures need to address operation of both air handling simultaneously as is done in the summer.
Clarification should be provided to the procedure which a s opera-l (2) tion with the control room at a high temperature so that it includes g
1 instructions which restore control room integrity in the event of a toxic gas challenge.
The proposed loss of ventilation test should incorporate a temperature (3) criteria such that the tests is halted when either staa@ state temperature is reached and the control room temperature remains constant or the temperature rise is such that the instrumentation and the equipment l
in the control roos are threatened.
Other observations and information are presented in the Enclosure which is the The ANL report does not consti-AHL report covering the Fort Calhoun Survey.
tute the NRC staff s position regarding these items, i
We request that you review the above observations and provide confirmation within 45 days tut your analyses ar.d regulatory commitments regarding the Fort Calhoun Station control roon ventilation system are still valid. Otherwise indicate those changes you propose and the schedule for their taplementation.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents, therefore, 02 clearance is not required under P.L.96-511.
Sincerely, f.c/
i Walter A. Paulson, Prokett Manager Pro"ect Directorate'-
V g
Divlsion of Reactor Pro;ects - III, IV, V and Special Pro;iects
Enclosure:
As stated cc w/ enclosure:
See next pa p DISTRIBUTION Docket M1e NRC PDR Local PDR PD4 Reading j
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- ^E'. F. Schroeder i
JAcalvo P. Noonan i
WPaulson Kraig i
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OGC-8ethesda EJordan l
JPartlow Acts (10)
Fort Calhoun Plant File i
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July 2, 1987 i
MEMORANDUM FOR: Blaine Murray, Chief FROM:
John J. Hayes, Jr., Project Engineer Project Directorate II-1
SUBJECT:
STATUS OF ISSUES INVOLVING CONTROL ROOM' HABITABILITY SURVEY OF REGION IV PLANTS I
During a June 1987 telephone call with you, you requested that the status of the issues which remain open for plants involved in the control room habitability survey be provided to you.
The status is as follows:
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- 1) The status of the Cooper Station is reflected in the memorandum to John Craig, Chief, Plant Syutems Branch from William Long, Cooper Project Manager dated June 9, 1987 and enclosed with this memorandum as Attachment 1.
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- 2) The findings of the survey of the Fort Calhoun survey have been transmitted to the licensee in a letter dated May 28, 1987 and a response was requested within 45 days.
This response will be reviewed by the Plant Systems Branch.
A copy of the letter transmitted to the licensee is included as to this memorandum.
- 3) The ANO report was issued to the Unit 1 and. Unit 2 Project Managers on July 1987.
A copy of the i
report is to be issued to the licensee by July l
1987.
If you have any questions concerning the status described above or in Attachments 1 or 2, please contact either myself or the plant's project manager.
1 John J. Hayes, Jr.
Project Engineer cc: E. Adensam R. Bangart J. Craig G. Dick R. Lee W. Long W. Paulson i
3, J. _ 2 GE7 ATTACHMENT 3 1
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MEMORANDUM FOR:
Robert S. Lee, Project Manager DISTRIBUTION Project Directorate IV Docket No. 50-313/
i Division of Reactor Projects - III, PDR
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IV, V and Special Projects G. Lainas S. Varga George F. Dick, Jr., Project Manager E. Adensam Project Directorate IV PD21 r/f Division of Reactor Projects - III, J. Hayes IV, V and Special Projects FROM:
John J. Hayes, Jr., Project Engineer Project Directorate II-1 Division of Reactor Projects I/II
SUBJECT:
SURVEY OF ANO UNITS 1 AND 2 CONTROL ROOMS Enclosed are copies of the NRR and Argonne National Laboratory (ANL) reports l
providing the results of the control room habitability survey of ANO Units 1 J
and 2.
This is one of eleven plants visited. This is the tenth report issued.
When all of the reports have been issued, the overall findings will be pre-sented in a NUREG/CR.
The findings of this survey are enumerated in Enclosures 1 and 2.
1 is the ANL summary report on the survey, while Enclosure 2 is NRR's report.
l These findings have been discussed with the licensee at the exit meeting and in subsequent discussion. Consistent with the August 8, 1985 memorandum to R. L.
i Bangart of Region IV from Dan Muller of NRR, a copy of these findings is being l
l provided to Region IV.
22-23, 1986, a survey was conducted at the AN0 During the period of January Plant. The survey was performed by John Driscoll and Roy McConnell of ANL and Jack Hayes of the Plant Systems Branch, Division of PWR Licensing - A.
The purpose of the survey was to evaluate:
(1) the operation of the control room ventilation system and its ability to maintain the ANO Units 1 and 2 control rooms habitable and (2) the adequacy of the technical specifications and procedures to demonstrate these systems' operability and capability consistent with the assumptions made in the ?icensee's TMI Action Item III.D.3.4,'" Control Room Habitability" analysis and the NRC staff's associated safety evaluation.
The survey team's findings cover system operation and design, plant technical specifications and procedures, and the III.D.3.4 analysis. The survey team was unable to obtain flow rate data in various portions of the control room ventilation system with the system operating in either its normal or emergency radiological or toxic gas operating. modes.
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. Due to the lack of flow measurements, it was impossible to verify whether the ANO Units 1 and 2 control room ventilation systems were performing in accordance with their TMI Action Item III.D.3.4 submittals.
- However, capability of the systems to meet the modes of operation described in the submittals is questionable because:
1) design is susceptible to single failure; 2) design capability appears to never have been demonstrated; 3) design is similar to Trojan's; (see NRC Inspection Report No. 50-344/86-06) l 4) procedures have systems operating in a mode different from that described in the III.D.3.4 submittals (e.g., no isolation on a toxic gas signal and pressurization flow twice that presented in the l
l submittals);
5) credit taken for Unit 1 system being redundant to the Unit 2 systeni when the protection afforded is not equivalent; 6) technical specifications are inadequate to demonstrate system capability and, in some cases, are at a level less than that asrimed in the III.D.3.4 submittals; and 7) capability of the system to maintain the control room at a positive pressure of 1/8 inch water gauge with respect to adjacent areas is not demonstrated on a periodic basis.
By this memorandum, I am rsequesting that a copy of these reports be provided to the licensee so that they may address the concerns which are outlined above and in the enclosed reports. Those concerns which involve plant procedures and compliance with technical specifications will ultimately be the responsibility of Region IV to resolve. Those concerns which involve operation in accordance with the III.D.3.4 submittal and its associated safety evaluation and the adequacy of plant technical specifications will be the responsibility of HRR to I
resolve.
John J. Hayes, Jr., Project Engineer Project Directorate 11-1 Division of Reactor Projects 1/11 cc:
J. Craig B. Murray (Reg IV)
J. Driscoll (ANL-W B. Johnson (ANORI R. Bangart (Reg I PR
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14
ENCLOSURE 1 Arkansas Nuclear One a,
Page a PLANT VISIT $UMMARY REPORT 1.
Plant:
Arkansas Nuclear One 2.
Utility:
Arkansas Power and Light Company 3.
Location:
Russelv111e, Arkansas 4.
NRC Region:
IV 5.
Visit Date:
January 22-23, 1986 6.
Participants from Argonne National Laboratory:
J. O Driscoll R. J. McConnell 7.
Scope:
The plant visit was made to gather information on control room habitability - Generic Issue 83. Specifically, the Plant Technical Specifications we m 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.
Infomation relating to loss of cooling in the control room envalope, which may cause loss of plant instruments-tion problems, was reviewed to detemine the impact of such an event on continued p1Ent operations. Air flow and. temperature f
osasurements were taken in various places throughout the control room envelope.
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Findings:
8.1 General
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The control room HVAC system as it exists today has evolved from subsystems, one for Unit 1 and another for Unit 2.
Each subsystem has a nomal and emergency cooling system and an emergency filtration / pressurization system. These subsystems have evolved into a difficult system to functionally analyze and easily comprehend. This difficulty is compounded by the lack of a single system flow diagram. Existing technical specifications for both Units 1 and 2 address in some cases the same equipment but with different criteria. The result is confusion, in tems of system functional perfomance and in how the system operates in the off-normal and emergency modes. This was evidenced by the fact that the plant operat-ing staff did not fully understand the operation of the system, nor for that matter, could the review team fully*
evaluate the functional design of the system.
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Arkansas Nuclear One A
Pye 2 8.2 Safety Analysis The Control Room (CR) HVAC system was found to be as described in the USAR and the material provided by the utility (APE),
except as follows:
B.2.1 In preparation for the review, several maintenance l
and operating procedures were reviewed. The proce-dures were elect as to the purpose and method to be employed and in general are of the best we have l
reviewed.
B.2.2 The USAR and III.D.3.4 submittal says the control
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room envelope will be pressurized with 333 cfm on a i
high radiation challenge. We found when both i
control roces see a challenge from either radiation or toxic gas, two pressurization fans will start.
This would cause the control room to be pressurized by 666 cra.
8.2.3 The USAR is inconsistent with plant procedures on pressurization of the control room envelope during l
an isolation caused by a high toxic gas signal.
8.2.4 Based on plant procedures, toxic gas could be added to the control room envelope by having the emergency filter trains in operation with 333 cfm enkaup from adjacent areas. The utility and/or NRC should perfora a technical evaluation to detetinine the best method for protecting the operators during a toxic gas release, i.e., filtering and pressurization or total isolation.
8.2.5 The radiation dose to control room operators during a LOCA is based on 3 cfm unfiltered ingress-egress air leakage. The III 0.3.4 submittal edicates that 3 efs is used instead of 10 cfm because of the use of a vestibule arrangement at each entrance door.
We found only one true vestibule. The other entrances are through shift supervisor's offices, or a kitchen. These areas have their own ventilation systems and are not considered vestibules. The radiation exposure, during a LOCA. should be based on 10 cfe unfiltered ingress-egress air leakape plus any system leakage into the control room enve ope.
8.2.6 The two charcoal adsorber units (emergency filter trains (2V5F-9 and V3F-9) are considered redund. ant units. Both units take suction and return to the Unit 1 side of the control room and both could be actuated at the same time.
It is suggested that any time the emergency filter trains are actuated, that f
c Arkansas Nuclear One Page 3
,e the emergency air conditioning system also be l
This would provide a more even sixing'of actuated.
the air in both control rooms. - At present there is no method provided to mix the air in the two centrol rooms unless the emergency air conditioning system is on.
m Emergency filtration unit 2VSF-9 is actuated by a single process radiation monitor, which samples air 8.2.7 in the Unit 2 supply duct.
Emergency filtration unit VSF-9 is actuated by an area radiation monitor g
l These l
located on a wall in the Unit 1 control room.
detectors are not redundant and will not cause Itissup-I actuation on the some response time.
gested that additional radiation monitors be p aced in the Unit I and LMit 2 air intake lines to that a control logic can be used to actuate only one emer-The C1 detectors should also pency filter train.be connected in a similar control logic arrangemel 8.3 Technical Specifications
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The plant is operated and surveillance is performed in accor-
- However, dance with the existing Technical Specifications.
the following changes art; recommended to better monitor the performance of the control room HVAC system.
Since the Unit I and Unit 2 control roces are con.
8.3.1 sidered one area, the Technical Specifications for both units should be identical.
Presently, the Technical Specification surveillance 8.3.2 procedures are contained separately in a Unit 1 These procedures procedure and a Unit 2 procedure.
should be combined into one procedure.
Thera should be a temperature limit specified based Surveillance should be 8.3.3 on equipment qualification.
performed periodically to verify that equipment temperature is less than the temperature limit operating (i.e., once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />) grade) system specified with the normal (nonsafety. A periodic test should also be run to verify the emergency air-conditioning system is capable of performing its The 'Jnit 2 Technical Specification function.
requires the emergency air-conditioning system to be tested for one hour, maintaining control room This test does not meet temperature below 84*F D8.
the design intent in that only Unit 2 normal cooling system is shutdown, while the Unit i normal cociing We recommend that the systas continues to operate.
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l test time be extended and that the Unit 1 and 1Jnit 2 I
nomal systems be shut down.
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8.3.4 Technical Specifications should include good engi-neering practices employed in Attachment 8.1 of Procedure 1802.06, e.g.. visual inspection of the system before testing HEPA filters and charcoal adsorbers in place.
8.3.f Equipment addressed by a Technical Specification should be identified by equipment number so that there is no confusion as to what equipment the specification applies (see Specification 3.9 for Unit 1).
8.3.6 It is not necessary to perfom an in-place test of the HEPA filter or charcoal adsorber after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation. However, it is necessary to perform a freon test after sempling the charcoal due to the manner of sempling tray-type charcoal adsorbers or if the grain-thief sample method is used on deep bed absorbers.
8.3.7 The Laboratory tests for charcoal for Units 1 and 2 5
should be conducted under similar test conditions and the same test method, A$1M D3803-1979 should be used. The test should be performed at a temperature of 30*C and a relative humidity of 955 unless AP&L consents to actuate the emergency air-conditioning units whenever the emergency filtration unit is activated. The technical specifications should also include a test (monthly) demonstrating the capa-l bility of the air-conditioning units.
If the design l
of the emergency chilling unit is 84*F D8 then relative humidity could be specified at praater than 1
705. The allowable penetration should a so be specified.
8.3.8 System flow rate should be specified in all speci-fications.
8.3.9 Since AN0 considers the HEPA filters and charcoal adsorbers to be active components in Specification 3.9.2 (Unit 1), an interpretation should be included in the bases that explains that these units are con.
sidered active components rather than passive com-ponents.
8.3.10 Specification 7.5.3.9.1.b for Unit i specifies an incorrect allowable penetration for the laboratory test for charcoal. The value stated is less than that assumed in the safety analysis.
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Arkansas Nuclear One
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Page 6 8.3.11 The tests enumerated in specification 4.10.3 for Unit 1 should also be perforced after any structural maintenance on the HEPA filter and charcoal adscriier housings or their internals.
8.3.12 Acceptance criteria for in-place testing or after replacement of charcoal adsorber banks and/or HEPA filters should specify acceptance criteria and test method.
8.3.13 There is an inconsistency in the acceptance criteria for in-place DOP testing of HEPA filters (S>ecifi-cation 4.7.6.1.2.b.a. and 4.7.6.1.2.c. for 'Jnit 2 i.e.
0.055 penetration versus 15 penetration).
8.3.14 The Technical Specifications are not clest on the number of lateratory semples required for the emer-gency filtration units. There should be three samples specified. One should be from the 2-in.
makeup air filter unit 2VFC-21 one from 2-in. recir-culation filter 2VFC-2A; and the other from the 4-in. 2VFC-8.
8.3.15 There seems to be a breakdown between the intent of 1
the safety analysis and the Technical Specification /
surveillance procedures regarding isolation time required during a C1, event. We believe Specifi-cation 4.7.61.2.d.2 for Unit 2 should be five i
seconds rather than 10 seconds.
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1 8.3.16 Since the safety analysis assumes that tb E trol j
room is pressurized to 1/8-in.. we believe a i
periodic pressurization test should be performed.
l 8.3.17 Technical Specifications should include a demon-stration that emergency makeup air despers to the emergency filter trains isolate on C1 signal.
These isolation valves should be closed 10 sec.
after C1: is present in the inlet ducts. This allows five seconds for detection and five seconds for isolation.
8.3.18 While reviewing the laboratory test results. it was noted that the laboratory contracted to perfore the test did not test the charcoal to the conditions specified in the contract. The charcoal was tested at 130*C instead of 80'C.
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8.3.19 The Technical Specifications require the emergency air filtration systems to be operated for one hour. Consideration should be given to reducing
Arkansas Nuclear One s e
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Pye 6 this time to 15 minutes. This time should be,ade-I quate to verify the o>erability of the emerftency filter trains since tiey are not equipped w<th heaters.
8.4 HVAC Flow and CRE Temperature Measurements We were unable to take any meaningful air flow B.4.1 measurements in the CR HVAC system because the test penetrations available were smaller than the test g
probe of our hot wire anemometer.
8.4.2 Air flow measurements were taken at the louvers between Units 1 and 2.
The results of these sea-surements were that approximately 1600-2000 cfm of l
air was flowing from Jnit 2 to Unft 1.
This sug-j gests that there may be a lot more air leakage in the Unit 1 side than is generally believed. ANO should look into this to determine if a problem exists or if air flow balancing is needed.
8.4.3 Air temperature was measuesd in both control Unit 2 was operating at full power.and rooms.
Unit I was shut down. The control room ambient l
temperature for Unit 1 averaged 72.8'F and the l
Unit 2 ambient temperature averaged 74.1*F. Tem-l perature taken inside of instrument cabinets for Unit 1 averaged 76.6'F and Unit 2 cabinets averaged 77.7*F.
These measurements would indicate that there is not much difference in the average temperature between shutdown conditions and operating conditions its the control room, The arrangement of the emergency filtration system 8.4.4 is so that there is no ductwork interconnection with the normal ventilation system. Although we were not able to aske air flow measurements, we believe that this arrangement provides relatively zero flow through the emergency filters chring norms 1 system operation (i.e., emergency filter train isolation The bladder-type valve used in the valves shut).
Unit 1 emergency filter train appears to provide a We believe that this system design tight isolation.
concept is one of the best we have seen to date.
However, actual systen flow measurements should be made to verify the integrity of this sytem design concept.
ANO should make measurements in the control room 8.4.5 HVAC systems to verify the leak tightness of valves
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(despers) used in both the normal ventilation trains and the emergency filter trains. These measurements should be used to determine unfiltered air inleakage.
8.5 Outside Air Infiltration 8.5.1 In review of the USAR and the !!!.D.3.4 Eubmittal, it is easily concluded that the design infiltration is 3 cfs. This value is assumed using a double-door vestibule arrangement. We feel that the value used should be at least 10 cfm since three of the so-called vestibules are two shift supervisor's offices and a kitchen area. These areas are i
supplied unfiltered air free the turbine building.
8.5.2 Usi a value of at least 10 cfs, unfiltered air i
inf tration requires that the radiation dose to the control room personnel be recalculated.
8.5.3 The control room envelope was determined to have i
ambient pressure positive with respect to the Unit 2 shif t supervisor's office but negative with respect to the Unit 1 shift supervisor office. These determina-tions were made by observing sucke flow patterns.
8.6 LER Evaluation There have been no LER's reported that would indicate that loss i
of cooling to the control room HVAC system has occurred at Arkansas Nuclear One. However, the Technical Specifications do
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not require an adequate surveillance test to determine that the f_
asergency ventilation system will maintain the temperature at b
thedesiredlevel(seeFinding8.2.3).
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ENCLOSURE 2 l
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NRR FINDINGS ANO UNITS 1 AND 2 CONTROL ROOMS l
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By: Jack Hayes X27214 I
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s NRR FINDINGS ANO UNITS 1 AND 2 CONTROL ROOMS On January 22 - 23, 1986 Jack Hayes from the Plant Systems Branch (PWRL-A)
I and John Driscoll and Roy McConnell of Argonne National Laboratory met with representatives of Arkansas Power and Light (AP&L) to perform a survey of the ANO Units 1 and 2 control rooms.
ANO was the fourth in a series of 12 operat-ing plants to be visited.
I The purpose of the survey was to evaluate:
(1) the operation of the control room ventilation system and its ability to maintain the ANO Units 1 and 2 con-trol rooms habitable and (2) the adequacy of the plant's technical specifica-tions and procedures to demonstrate system operability and system capability consistent with the assumptions made by the licensee in the plant's TMI Action Item Ill.D.3.4, " Control Room Habitability" analysis and the NRC staff's associated safety evaluation.
It appears that the Unit I habitability systems were designed using one set of criteria and that Unit 2 had its habitability systems designed under a differ-l ent set of criteria and that this change in criteria had occurred in the midst l
of the Unit 2 design. While an attempt was made to integrate the two designs, i
the integration was neither complete nor was it sufficient to ensure consis-tency between the two units. This is evident in that there did not exist at the facility a one line diagram of the habitability systems which depicted their configuration and their interdependence. Consequently, there is a great deal of ambiguity when one attempts to understand the systems and their modes of operation from the system descriptions, station training manuals, proce-dures and updated FSAR's.
Indeed, AP&L claims that the Unit 1 system can be utilized as a backup for Unit 2 and vice versa; and the technical specifications seem to imply that redundant systems are present in each unit.
However, the manner in which the two systems are designed and configured is such that the two systems are not truly
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. redundant. To make the two systems truly redundant would probably require some alterations to the systems' control logic and some additional radiation monitoring equipment.
If either the Unit 1 or the Unit 2 habitability systems experienced problems, then it is unclear whether the proper actions would be taken by the affected control room operators because it is questionable whether this interdependence has ever been conveyed to them.
From the survey team's review of the ANO Unit 1 and Unit 2 III.D.3.4 submit-tals, the NRC staff's safety evaluation of these submittals, and each Unit's updated FSAR, the team concluded that the respective habitability systems are l
redandant to each other and therefore, the technical specifications for each l
Unit's control room habitability system should address the saw surveillance requirements and should include identical acceptance criteria. However, the conclusion that the survey team made when the procedures and the technical specifications for the two units were reviewed was that each unit operated as if the ventilation systems were independent of each other.
In fact, the surveillance requirements are different as are the acceptance criteria.
Such disparity should not exist if the two units' control room habitability systems are redundant.
The following items reflect the conclusions drawn during this visit.
1.
The emergency chilling units do not appear to have been adequately tested to demonstrate their capability to cool the ANO control rooms.
Discussion:
During normal operation, control room cooling is provided by non-safety grade chillers, either VHC-7A or 7B for Unit 1 and 2VHC-7A or 7B for Unit 2.
ANO has, located in the Unit 2 control room, two redundant safety grade chillers, 2VUC-27A and 2VUC-27B, for cooling both the Unit 1 and the Unit 2 control rooms l
which are utilized during emergency operation.
In addition, there remains a safety grade system, previously associated with Unit 1, that is still i
4 l functional but has only 40% of the capacity of the 2VUC-27A and 278 chillers.
ANO does not appear to have adequately tested the 2VUC-27 chillers to deter-mine whether either is capable of maintaining control room equipment below i
its equipment qualification temperature. The testing procedure for one of the 2VUC-27 trains always had the Unit 2 normal operating chiller shut down.
l However, Unit l's normal operating chiller is always operating in its nonnal mode, thereby providing supplemental cooling to the control rooms and never providing an adequate test of the capability of the safety grade chillers.
An SR0 indicated to the survey team that an incident had occurred in 1980, where they had to operate the safety grade chillers for 14-16 days with the 1
normal control room chilling units off and that during this period the control room ambient temperature reached the upper 80's.
However, the SRO attributed this heatup to a problem of maintaining Freon in the 2VUC-27 l
units. The SR0 indicated that the Freon problem has since been corrected and that ANO is planning on altering their test procedure for safety grade 4
chillers to ensure that neither normal makeup air nor the cooling capability f
l associated with the the normal operating chillers biases the results of the test. The survey team believes that this is an appropriate change.
- However, I
l despite this change, the present one hour test is an insufficient period of time to demonstrate the cooling capability of the safety grade chillers.
Licensees with similar systems conduct 10-12 hour tests (e.g., Calvert Cliffs and Trojan) to demonstrate this capability; and even this period of time may not be long enough. The survey team believes that because the cooling capabil-ity of the safety grade chillers needs to be demonstrated on a routine basis, I
the length of this test should be based upon a duration sufficient to demon-strate that an equilibrium temperature has been reached. This equilibrium l
temperature should be well below the equipment qualification temperature.
If the test indicates that the temperature rise would eventually result in the i
equipment qualification temperature being exceeded then the test should be halted. The licensee should then take action to bring conditions back to a state where the equipment qualification temperature would not be exceeded.
It is expected that several hours would be required for the test.
2.
AP&L should modify plant procedures for the control room ventilation system to have the control room isolated in the event of a toxic gas challenge or reanalyze the toxic gas evaluation.
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- I Discussion
'1 The toxic gas review performed by the NRC assumed from the ANO s0bmittals that the control room is isolated during a toxic gas challenge.
However, a review l
of plant procedures shows that during a toxic gas challenge the control room is pressurized by taking 333 cfm of makeup air from either the controlled access l
area located in the auxiliary building, or from the computer room of Unit 1.
This is contrary to NRC recommended practice in SRP 6.4 and Regulatory Guide 1.95 which require isolation of the control room.
In addition, a January 10, 1980 letter from D. Trimble of AP&L to R. W. Reid of the NRC and a March 13, 1981 letter to D. G. Eisenhut of the NRC indicate that the control room is isolated from outside air during a toxic gas challenge.
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AP&L needs to review the manner in which they operate during a toxic gas chal-enge to ensure that plant procedures are consistent with their 111.D.3.4 submittals and the NRC safety evaluation.
3.
The technical specifications for Unit 1 and Unit 2 should be similar.
I Discussion If the Unit 1 and 2 control room emergency filtration and chilling units are going to be treated as redundant, then the technical specification l
requirements for each Unit's habitability systems, their tests, and the acceptance criteria for the tests, should be identical. Attachments 1 and 2 contain listings of some of the suggested changes to the technical specifi-cations which should be made to ensure consistency between Units 1 and 2 and to ensure that the habitability systems are capable of demonstrating system performance consistent with the assumptions made in the III.D.3.4 submittal.
4.
A possible item of noncompliance with a Unit 2 surveillance requirement covering laboratory testing of the charcoal was found.
In addition, the surveillance of the charcoal is conducted at an inappropriate temperature.
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... Discussion The surveillance requirements associated with the Unit 2 laboratory test of chcrcoal requires that it be performed in accordance with Table 2 of Regulatory Guide 1.52.
This means that the test is to be done at 80 C.
Fron' data pre-sented in AN0's two contractors' reports from 1982 - 1984, it appetrs that all tests were performed at 130*C.
Not only were the tests conducted at an impro-per temperature, but the test conditions would have resulted in a prediction of charcoal adsorber removal capability greater than that which could be assumed if the test were conducted at 80*C.
The performance of a laboratory test of the charcoal at either 80'C or 130'C would overpredict the capability of the charcoal to perform its intended function, because the performance of the test at these temperatures regen-erates the charcoal adsorber material and because the control room makeup air would never approach these temperatures.
In order to determine the true capability of the charcoal, the test should be performed at 30'C.
Conse-quently, the survey team recommends that the technical specification be changed to require that the laboratory test of the charcoal be performed at 30*C using a modified version of the ASTM D3803 test method.
5.
ANO needs to perform a system test en its control room ventilation system to demonstrate its capability to perform as it was described in the 111.0.3.4 submittals.
Discussion The survey team was never able to verify whether the control room habitability systems were. capable of performing their intended function because an insufficient number of flow test ports existed and those that did exist were too small in size to accomodate the team's hot-wire anemometer.
Because of this lack of test ports, it appears that the operation of the control room normal and emergency ventilation system has never been verified. 8ecause the ANO design is similar to that at Trojan and because of the problems identified at Trojan (refer to NRC Inspection Report No. 50-344/86-06), such measurements would be appropriate.
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, The survey team is concerned that the present design may be incapable of maintaining a positive pressure of 1/8 inch water gauge in the control room relative to all adjacent areas. This concern exists because a review of a Unit 2 drawing (M-2263, Sh.2) seems to indicate that there are no isolation dampers in the flow path from the normal outside air intake.
Consequently, if the control room habitability systems were responding to a radiological challenge, it is questionable whether the control room could be pressurized to a positive pressure of 1/8 inch water gauge with respect to adjacent areas with only 333 makeup air because the pressurized control room would have a direct exhaust path to the outside air intake.
In the event of a toxic gas challenge, the control room, if it functioned in its isolation mode, would be susceptible to receiving, via the same direct path, toxic gas into the control room envelope. Such a path could negate the ANO toxic gas analysis.
l Another problem with the Unit 2 cesign which involves susceptibility to single failure, again brings into question the capability to pressurize the control room to 1/8 inch water gauge and to maintain control room integrity consistent with the ANO toxic gas analysis.
Because the intake from the control access l
area to the emergency filter unit and tne purge outside air intake itself each contain only a single damper, failure of eii.her damper would again provide an f
l immediate path either into or out of the control room as oescribed above depeno-
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ing upon the circumstances. A similar problem exists for the Unit I design.
Because f.he Unit 1 computer room loses its air conditioning in the event of the actuation of the control room habitability systems, the computer room will increase in temperature. This will create an increased pressure in the com-puter room such that it may be at a higher pressure than the control room and a source of in-leakage into the control room and into the control room venti-lation equipment. This leakage would be unfiltered, contaminated air..Because of the above noted design concerns and because a majority of the dampers utilized for isolation in the ANO control room;ventil6 tion systems are louvered, the ability to maintain control roorn envelope integrity is question-able and needs to be demonstrated along with the ability to pressurize the l
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-7 control room to 1/8 inch water gauge with 333 cfm.
6.
The instrumentation and control logic for chlorine and radiation channels should be identical and redundant for Unit 1 and Unit 2.
Discussion For Unit 1 a high radiation signal is senseti by an area radiation monitor in the Unit I control room while for Unit 2 the high radiation signal is initiated from the radiation monitor located in the intake duct. The survey team determined that if a radiation incident occurred, the intake radiation I
monitor for Unit 2 would annunciate prior to the Unit I area radiation monitor annunicating. The survey team believes that initiation as a result of j
actuation by a radiation monitor should be identical in Unit 1 and Unit 2.
Therefore, both the Unit 1 and Unit 2 air intakes should have identical radiation monitoring schemes which are also redundant. A similar problem exists for C1 detection.
2 For the Unit I and the Unit 2 control room habitability systems to be truly redundant, then the CL detectors should have equal capability of isolating the 2
control room. They do not presently possess this capability at ANO. For example, although there are two C1 detectors, 2CLS 8761-1 & 2CLS 8760-2, in 2
the Unit I supply ductwork to the control room and two CL2 detectors, 2CLS 8762-2 & 2CLS 8763-1, in the Unit 2 supply ductwork to the control room, a signal from one of the monitors, 2CLS 8761-1, will not result in the shutdown of the Unit I normal air handling units VSF-8A and VSF-8B.
In the case of the i
Unit 2 normal air handling units, VSF-8A and 2VSF-8B, only one of the monitors, 2CLS 8761-1, causes the air handling units to be shutdown. This same monitor is also the only monitor which will result in the shutdown of the Unit 2 exhaust fans 2VE."-43A and 2VEF-43B.
Both the Unit 1 and the Unit 2 emergency filter units, one of which is intended to function in the event of C1 2 challenge to the control room, are only actuated by two of the four C1 monitors.
7 Unit 1 is actuated by 2CLS 8761-1 and 2CLS 8762-1.
It would appear that a more appropriate and consistent logic scheme would have each CL detector capable of 2
isolating both the Unit 1 and Unit 2 control room intakes and shutting down each exhaust fan for the control room.
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I 7.
The emergency chillers should automatically start on an isolation of the normal control room makeup.
i Discussion:
Presently, the emergency chillers are actuated manually by the control room operators if they determine a need.
Discussions with the operators j
indicated that the operators would probably start the units shortly after the isolation signals.
Consideration should be given to starting the chillers 4
l immediately on an isolation signal.
If the operator waits until the'need exists, then if one of the chilier units fails to start, a 10-15 minute period occurs in which the control room continues without cooling due to the built-in timers in the compressors.
Past events at the McGuire Plant and other operating reactors have demonstrated the susceptibility of solid state instrumentation to failure when control room ambient temperatures are approximately 85'F.
(Refer to IE Information Notice 85-98 and to AE0D Report C604).
In order to minimize the probability of such an event occurring and in order to give control room operators more time to react to a situation, the emergency chillers should be actuated imediately after the control room is either isolated or placed in the emergency filtration mode of operation.
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9 Att'achment 1 ANO UNIT 1 TECHNICAi. SPEC 1FICATIONS 1.
Unit l's specifications should be similar to Unit 2's.
If the Unit 2 system is a backup to Unit 1, then the Technical Specifications for both units need to be similar so that equal quality and performance is ensured.
Unit I and Unit 2 share a common control room envelope. Therefore, surveillance requirement tests should be identical as should the accep-tance criteria for these tests.
2.
The control room should have a temperature limitation for equipment j
qualification.
3.
It is not necessary to perform an in-place test of the HEPA filter or charcoal adsorber after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of system operation. However, it is necessary to perform a Freon test after sampling the charcoal if test canisters are not utilized to. sample tray-type charcoal adsorbers or if the grain-thief sample method is used on the deep bed adsorbers.
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Consistent with the Unit 2 technical specifications, the Unit I technical j
specifications should include the practices employed in Attachment 8.1 of Procedure 1802.06, e.g. visual inspection of the system before testing the HEPA filters and charcoal adsorbers in-place.
5.
Specification 3.9 should identify the units that are covered by this specification because there is not a redundant emergency air filtration unit.
If the Unit 2 system is considered a backup to Unit 1, then it should be indicated.
6.
The laboratory tests for charcoal for Units 1 and 2 should be conducted under similar test conditions and using the same test method. ASTM D3803-1979 should be used. The test should be performed at a temperature-i of 30'C and a relative humidity of 95%' unless AP&L commits to actuating the emergency air conditioning units whenever the emergency filtration unit is activated and the Technical Specifications' include a monthly
10 ANO UNIT 1 TECHNICAL SPECIFICATIONS test demonstrating the capability of this air conditioning unit.
The laboratory test should be performed with a velocity consistent with a 0.25 second residence time per 2 inches of bed unless the systems at ANO do not have at least this amount of residence time.
The velocity should be adjusted accordingly in that event.
7.
System flow rate should be specified in all specifications.
8.
Technical Specification 3.9.2 should be reworded because it appears to allow the units to operate 7 days without the HEPA filters and charcoal adsorbers (passive components) being operable even though the licensee indicates that these components are treated as active.
Possible solution is to clarify in the bases.
9.
An incorrect allowable penetration is included in the laboratory test for charcoal (7.5.3.9.1 b). The allowable penetration is less than that which was assumed for the Ill.D.3.4 analysis.
- 10. The tests enumerated in surveillance requirement 4.10.3.a should also be performed after any structural maintenance on the HEPA filter and charcoal adsorber housings or their internals.
- 11. Surveillance for in-place testing after replacement of charcoal adsorber banks and/or HEPA filters should specify acceptance criteria and test method.
- 12. The comments made on Unit 2 technical specifications should be reviewed as to their appropriateness for Unit 1 as similar comments were not always made for each unit.
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o o Attachment 2 4
ANO UNIT 2 TECHNICAL SPECIFICATIONS 1.
The testing of the control room emergency air conditioning system to demonstrate that the unit can maintain the control room temperature below 84*F DB (dry bulb temperature), when operating for one hour is an insufficient time to demonstrate the capability of the system. A more appropriate test time should be 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> or until an equilibrium temper-ature is reached. (4.7.6.1.1.a.2) 2.
The laboratory test for the charcoal should be conducted at 30*C, The relative humidity for this test must be specified as 95% if the design of the emergency chiller is 84*F dry bulb, since then relative humidity could be greater than 70%.
3.
Test conditions for the laboratory test of charcoal should be specified along with the allowable penetration and the test method.
(See notc on Unit I specifications.)
4.
There is an inconsistency in the acceptance criteria for in-place DOP testing of HEPA filters (surveillance requirements 4.7.6.1.2.b.a and 4.7.6.1.2.e, i.e. 0.05% penetration versus 1% penetration). They should both be 0.05% to be consistent with the licensee's III.D.3.4 analysis.
5.
To ensure consistency with the III.D.3.4 analysis and because the Unit 1 filter unit is redundant to the Unit 2 filter, the laboratory test for the charcoal should specify 3 laboratory samples.
From the Unit 1 system one sample would come from the 2-inch make-up air filter unit VFC-2A and the other sample from VFC-2, the 2-inch recirculation filter.
From the Unit 2 system the sample would come from the 4-inch adsorber bed, 2VFC-8.
(Also applicable to Unit 1.)
6.
If the safety evaluation for the ANO control rooms is based upon isolation of normal ventilation and exhaust 5 seconds after detector trip, then surveillance requirement 4.7.6.1.2.d.2 should be 5 rather than 10 seconds.
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l Attaciiment 2 ANO UNIT 2 TECHNICAL SPECIFICATIONS 7.
Technical specifications should require a pressurization test with the control room at 1/8 of an inch water gauge with respect to all adjacent areas.
(Also applicable to Unit 1.)
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8.
Technical specifications should include a demonstration that emergency makeup air dampers isolate on C1 signal.
(This demonstration is 2
also applicable to Unit 1.)
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