ML20198M351
| ML20198M351 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 12/23/1998 |
| From: | Nolan M Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20198M355 | List: |
| References | |
| NPF-06-A-194 NUDOCS 9901050317 | |
| Download: ML20198M351 (13) | |
Text
.
i j A %fo A'
UNITED STATES f,
,j NUCLEAR REGULATORY COMMISSION t
WASHINGTON D.C. 30666 4001
+s...../
ENTERGY OPERATIONS. INC.
DOCKET NO. 50-368 ARKANSAS NUCLEAR ONE. UNIT NO. 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No.194 License No. NPF-6 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Entergy Operations, Inc. (the licensee) dated May 18,1998, as supplemented by letter dated December 8,1998, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance: (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this license amendment will not be inimical to the common defem ' and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
i 9901050317 981223 PDR ADOCK 050003 8 P
. _ _. _ _. _ - _ ~.. _...
e 2.
Accordingly, the license is amended by changes to the Technical Specifications as l
indicated in the attachment to this license amendment, and Paragraph 2.C.(2) of Facility l
Operating License No. NPF-8 is hereby amended to read as follows:
2.
Technical Soecifications l
The Technical Specifications contained in Appendix A, as revised through Amendment No. 194, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.
3.
The license amendment is effective as of its date of issuance to be implemented prior to the facility's restsd from refueling outage 2R13.
l FOR THE NUCLEAR REGULATORY COMMISSION h.
5;f-l M. Christopher Nolan, Project Manager Project Directorate IV-1 l
Division of Reactor Projects Ill/IV i
Office of Nuclear Reactor Regulation i
l
Attachment:
Changes to the Technical Specifications Date of issuance: December 23, 1998 l
l l
l l
r b
ATTACHMENT TO LICENSE AMENDMENT NO.124.
FACILITY OPERATING (ACENSE NO. NPF-6 DOCKET NO. 50-368 Revise the following pages of the Appendix "A" Technical Specificatiens with the attached pages. The revised pages are identified by Amendment number and contain vertical lines indicating the area of change. The corresponding overleaf pages are also provided to maintain document completeness.
REMOVE PAGES INSERT PAGES vil vii XII Xil 3/4 6-10 3/4 6-10 3/4 6-12 3/4 6-12 3/4 6-13 3/4 6-13 B 3/41-3 83/41-3 B 3/4 5-3 B 3/4 5-3 B 3/4 6-3 B 3/4 6-3 B 3/4 6-4 B 3/4 6-4 B 3/4 6-5 B 3/4 6-5 B 3/4 6-6 l
INDEX LIMITING CONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS SECTION PAGE 3/4.5.2 ECCS SUBSYSTEMS - Tavg 2300'F.......................
3/4 5-3 3/4.5.3 ECCS SUBSYSTEMS - Ta'rg 5300'F.......................
3/4 5-6 3/4.5.4 REFUELING WATER TANK.................................
3/4 5-7 3/4.6 CONTAINMENT SYSTEMS 3/4.6.1 PRIMARY CONTAINMENT Cantainment Integrity................................
3/4 6-1 Containment Leakage..................................
3/4 6-2 Containment Air Locks................................
3/4 6-4 Internal Pressure, Air Temperature and Relative Humidity..................................
3/4 6-6 Containment Structural Integrity.....................
3/4 6-8 Containment Ventilation System.......................
3/4 6-9a 3/4.6.2 DEPRESSURIZATION, COOLING, AND pH CONTROL SYSTEMS Containment Spray System.............................
3/4 6-10 Trisodium Phosphate (TSP)............................
3/4 6-12 Containment Cooling System...........................
3/4 6-14 3/4.6.3 CONTAINMENT ISOLATION VALVES.........................
3/4 6-16 3/4.6.4 COMBUSTIBLE GAS CONTROL H yd r o g e n An a l y' ? r s...................................
3/4 6-18 Electric Hydrogen Recombiners - W....................
3/4 6-19 Containment Recirculation System.....................
3/4 6-20 I
l 1
ARKANSAS - UNIT 2 VII
' Amendment No. 44,M4,194 l
1 l
gg
_ RASES SECTION IAGE 3/4.0 APPLTCABILITY..............................................
B 3/4 0-1 3/4.1 RFACTIVITY CONTROL SYSTEMS 3/4.1.1 SORATION C0NTROL........................................
B 3/4 1-1, 3/4.1.2 BORATION SYSTEMS........................................
B 3/4 1-2 3/4.1.3 MOVABLE CONTROL A38ENBLIES..............................
.'S 3/4 1-3 3/4.2 POWER DISTRIBUTION LIMITS 3/4.2.1 LINEAR BERT RATE........................................
B 3/4 2-1 3/4.2.2 RADIAt PEAx!NG rACTOR8..................................
3/4 2-2 3/4.2.3 AIIMUTMAL POWER TILT....................................
S'3/4 2-2 3/4.2.4 DNBR MARGIN.....................
,5 3/4 2-3 3/4.2.5 RC5 FLOW RATE.........
4................................
3 3/4 2-4 3/4.2.6 REACTOR COOLANT COLD I.EG TEMPERATURE....................
3 3/4 2-4 3/4.2.*1 AXIAL SHAPE INDEX............................'...........
& 3/4 2-4 3/4.2.8 PRESSURIZER PRESSURE....................................
B 3/4 2-4 3/4.3 INSTRUMENTATION 3/4.3.1 PROTECTIVE INSTRUMENTATION..............................
B 3/4 3-1 3/4.3.2 ENGINEERED SAFETY FTATURE INSTRUMENTATION................
B 3/4 3-1 3/4.3.3 MONITORING INSTRUMENTATION..............................
B 3/4 3-2 ARKANSAS - UNIT 2 XI Amendment No. 44,44,44,l91 JUL *? W
INDEX BASES PAGE SECTION 3/4.4 REACTOR COOLANT SYSTEM 3/4.4.1 REACTOR COOLANT LOOPS AND COOLANT CIRCULATION...........
B 3/4 4-1 3/4.4.2 and 3/4.4.3 SAFETY VALVES.................................
B 3/4 4-1
'3 / 4. 4. 4 PRESSURIZER.............................................
B 3/4 4-2 3/4.4.5 STEAM GENERATORS........................................
B 3/4 4-2 3/4.4.6 REACTOR COOLANT SYSTEM LEAKAGE..........................
B 3/4 4-3 3/4.4.2 CN EMI S T RY...............................................
B 3/4 4-4 3/4.1 8 SPECIFIC ACTIVITY.......................................
B 3/4 4-4 3/4.4.9 PRESSURE / TEMPERATURE LIMITS.............................
B 3/4 4-5 3/4.4.10 STRUCTURAL INTEGRITY....................................
B 3/4 4-11 l
3/4.4.11 REACTOR COOLANT SYSTEM VENTS............................
B 3/4 4-11 3/4.5 EMERGENCY CORE COOLING SYSTEMS (ECCS) l 3/4.5.1 SAFETY INJECTION TANKS..................................
B 3/4 5-1 3/4.5.2 and 3/4.5.3 ECCS SUBSYSTEMS..............................
B 3/4 5-1 3/4.5.4 REFUELING WATER TANK (RWT)..............................
B 3/4 5-2 3/4.6 CONTAINMENT SYSTEMS 3/4.6.1 PRIMARY CONTAIhMENT.....................................
B 3/4 6-1 3/4.6.2 DEPRESSURIZATION, COOLING, AND pH CONTROL SYSTEMS.......
B 3/4 6-3 l
3/4.6.3 CONTAINMENT ISOLATION VALVES............................
B 3/4 6-6 l
3/4.6.4 COMBUSTIBLE GAS CONTROL.................................
B 3/4 6-6 l
ARKANSAS - UNIT 2 XII Amendment No. M,M,4,194
O CONTAINMENT SYSTEMS CONTAINMENT VENTILATION SYSTEM LIMITING CONDITION FOR OPE. RATION 3.6.1.6 The containment purge supply and exhaust isolation valves shall be closed and handswitch keys removed.
g i
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTION:
With one or more containment purge supply and/or exhaust isolation valves not closed with the handswitch keys removed, place the valve (s) in the closed position with handswitch key (s) removed within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.1.6 The containment purge supply and exhaust isolation valves shall be determined closed at least once per 31 days.
l ARKANSAS - UNIT 2 3/4 6-9a Amendment No. 64 i
l l
COMTA2NMENT SYSTEMS 3/4.6.2 DEPRESSURIZATION, COOLING, AND pH CONTROL SYSTEMS l
CONTAINMENT SPRAY SYSTEM LIMITING CONDITION FOR OPERATION 3.6.2.1 Two independent containment spray systems shall be OPERABLE with each spray system capable of taking suction from the RWT on a Containment spray Actuation Signal (CSAS) and automatically transferring suction to the containment sump on a Recirculation Actuation Signal (RAST.
Each spray system flow path from the containment sump shall be via an OPERABLE shutdown cooling heat exchanger.
APPLICABILITY: MODES 1, 2, and 3.
ACTION:
With one containment spray system inoperabl.e, restore the inoperable spray system to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.2.1 Each containment spray system shall be demonstrated OPERABLE:
a.
At least once per 31 days by:
1.
Verifying that each valve (manual, power operated or automatic) in the flow path is positioned to take suction from the RWT on a Containment Pressure-High-High test signal.
2.
Verifying tSat the system piping is full of water from the RWT to at least elevation 505'(equivalent to > 12.5%
indicated narrow range level) in the risers within the containment.
b.
By verifying that each pump demonstrates degradation of s 6.3%
from its original acceptance test pump performance curve when tested pursuant to specification 4.0.5.
i i
l l
l ARKANSAS - UNIT 2 3/4 6-10 Amendment No.194
CONTAINMEMT SYGTEMS TRISODIUM PHOSPHATE (TSP) l LIMITING CONDITION FOR OPERATION 8
3.6.2.2 The TSP baskets shall contain 2 278 ft of active TSP.
APPLICABILITY: MODES 2.,
2 and 3.
ACTION:
With the TSP not within limits, restore the TSP to within limits within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and be in at least HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.2.2 The TSP shall be demonstrated OPERABLE:
a.
At least once per 18 months by verifying that the TSP baskets contain 2 278 f t* of, TSP.
b.
At least once per 18 months by verifying that a sample from the TSP baskets provides adequate pH adjustment of borated water.
I ARKANSAS - UNIT 2 3/4 6-12 Amendment No.194
THIS PAGE INTENTIONALLY LEFT BLANK l
, UNIT 2 3/4 6-13 kmendment No. G0,194
=-
REACTIVITY CONTROL SYSTEMS l
l l
l l
BASES l
The boron capability required below 200'T is based upon providing a suf ficient SHUTDOWN MARGIN af ter xenon decay and cooldown f rom 200*F to 140*F.
This condition requires either borated water from the refueling water tank or boric acid solution from the boric acid makeup tank (s) in accordance with the requirements of Specification 3.1.2.7.
The contained water volume limits includes allowance for water not available because of discharge line location and other physical l
characteristics. The 61,370 gallon limit for the refueling water tank is l
based upon having an indicated level in the tank of at least 7.5%.
t l
The OPERABILITY of one boron injection system during REFUELING ensures that this system is available for reactivity control while in MODE 6.
t The limits on contained water volume and bozon concentration of the boric acid sources, when mixed with the trisodium phosphate, ensures a long term pH l
value of 2 7.0 for the solution recirculated within containment after a LOCA.
l This pH limit minimizes the evolution of iodine and helps to inhibit stress corrosion cracking of austenitic stainless steel components in containment during the recirculation phase following an accident.
3/4.1.3 MOVABLE CONTROL ASSEMBLIES The specifications of this section ensure that (1) acceptable power distribution limits are maintained, (2) the minimum SHUTDOWN MARGIN is i
maintained, and (3) the potential effects of CEA misalignments are limited I
to acceptable levels.
l The ACTION statements which permit limited variations from the basic requirements are accompani l by additional restrictions which ensure that the original design criteria are met.
The ACTION statements applicable to a stuck or untrippable CEA or a large misalignment (2 19 inches) of two or more CEAs, require a prompt shutdown of the reactor since either of these conditions may be indicative of a possible loss of mechanical functional capability of the CEAs and in l
the event of a stuck or untrippable CEA, the loss of SHUTDOWN MARGIN.
CEAs that are confirmed to be inoperable due to problens other than addressed by ACTION a of Specification 3.1.3.1 will not impact SHUTDOWN MARGIN as long as their relative positions satisfy the applicable alignment requirements.
For small udsalignments
(< 19 inches) of the CEAs, there is 1) a small effect on the time dependent long term power distributions relative to those used in generating LCOs and LSSS setpoints, 2) a small effect on the available SHUTDOWN MARGIN, and 3) a small effect on the ejected CEA worth used in the safety analysis. Therefore, the ACTION l
l i
ARXANSAS - UNIT 2 B 3/4 1-3 Amendment No. G4,44,4G4,MN 94
\\
e EMERGENCY CORE COOLING SYSTEMS BASES The contained water volume limit includes an allowance for water not usable because of tank discharge line location or other physical l
characteristics.
The limits on contained water volume and boron concentration of the boric acid sources, when mixed with the trisodium phosphate, ensures a long term pH value of 2 7.0 for the solution recirculated within containment after a LOCA.
This pH limit minindzes the evolution of iodine and helps to inhibit stress corrosion cracking of austenitic stainless steel components in containment during the recirculation phase following an accident.
ARKANSAS - UNIT 2 B 3/4 5-3 Amendment No. Ma,194
coNTA2WMpm SYs? pts j
l shsts 3/4.6.2 DEPRESIUR22AT20W, cooLINC, AND sH c0NTROL SYsTDis l
f 3/4.5.2.1 CONTAINHENT SPRAY SYsTDI l
The OPERASILITY of the sentainment spray system ensures that i
sentainment depressurisation and oooling capability will be available in l
the event of a LOCA. The pressure reduction and resultant lower containment leakage rate are consistant with the assumptions used in the J]
assident analyses.
1 The sentainment oprey system and.the sentainment seeling system are j
redundant to each other in providing post accident cooling of the j
eentainment atmosphere. Newever, the containment spray system also l
i provides a mechanism for removing iodine from the containment atmosphere I
and therefere the time requirements for restoring an inoperable spray
]
system to CPERABLE status have been maintained consistent with that
}
assigned other inoperable Esr equipment.
3/4.6.2.2 TRIseDIUM PMCsPMATE f?87)
A hydrated foan of granular trisodium phosphate (Tst) is employed as a j*
passive fonn of pH control for post Inch containment spray and eere ese1 Lag j
water to ensure that iodine, which may be dissolved in the recirculated i
reactor cooling water following a loss of coolant accident (14cA), remains l
in solution. Ts? also helps inhibit stress corrosion stacking (Scc) of 1
austenitic stainless steel conponents in sentainment during the roeireulatten phase following an accident. Baskets of Tat are plaoed on the floor of the j
eentainment building to dissolve from released remotor emelant unter and containment sprays after a LOCA. Recirculation of the water for oore cooling j
and eentainment sprays then provides mixing to achieve a uniform solution pH.
J l
Fuel that is damaged during a LOCA will release iodine in several chemical forms to the reactor coolant and to the containment atmosphere. A pertion of the iodine in the containment atmosphere is washed to the sump by I
containment sprays. The emergency more cooling water is horated for reactivity control. This horated water causes the susy solution to be acidic. In a 4
low pH (scidic) solution, dissolved iodine will be converted to a volatile form. The volatile iodine will evolve out of solution into the containment i
atmosphere, significantly increasing the levels of airborne iodine. The j
increased levels of airborne iodine in containment contribute to the radiological releases and increase the consequences from the accident due to i
containment atmosphere leakage.
I After a LoCA, the sosponents of the core sooling and containment spray i
systems will be exposed to high tagerature borated water. Frolonged exposure j
to the core cooling water combined with stresses imposed on the cenponents can 1
cause sec. The see is a function of stress, euygen and shleride seamentrations, l
PE, tenparature, and alley sosposition of the components. Righ temperatures and low pu, which would be present after a LOCA, tend to promote Scc. This san lead to the failure of necessary safety systems or oosponents.
i Adjusting the pH of the resir'culation solution te levels above 7.0 j
prevents a significant fraction of the dissolved lodine from converting to i
a volatile fora.. The higher pH thus desroases the level of airborne iodine l
&n sentainmant and reduces the radiological consequences from containmant i
atmosphere leakage following a LocA. Maintaining the solution pk above 1.0 l
also reduces the occurrence of scc of austenitic stainless steal components
{
"in containment. Reducing SCC reduces the probability of failure of songonents.
1 ARXANSAB - UNIT 3' S 3/4 6-3 Amendment No. 44,194
)
i e
unen,.
.m
.~
i
)
_CONTAINMDf7 SYsTDIs ansts I
the containment building during normal operation.A hydrated form of TSP is Since the TSP is hydrated, it is less likely to absorb large amounts of water from the humid atmosphere and will undargo less physical and chemical change than the anhydrous goam or
}
tsp.
4 1
i The LOCA radiological consequences analysis takes credit for lodine retention in the sump solution based on the recirculacion water pH being k 7.0.
The radionuclide releases from the sentaitsent atmosphere and the sensequences of a LOCA wouis be increated it the pH of the assiseuistion
]
water were not adjusted to 7.0 or above.
The required amount of Tat is based upon the estreme cases of water 4
i volume and pH possible in the sentainment sump after a large break LOCA.
i The minimum required volume is the volume of TSP that will achieve a sump 1
solution pH of & 7.0 when taking inte seasideration the maxima possible i
sump water volume and the minimum possible PM.
The amount of Tap needed in the sentainment building is based on the mass of Tat required to achieve the desired PN.
since it is not feasible to weigh the entire amount of T3P in contain t
The minimum required volume is based on the manufactured density of Tst dodecahydrate.
humidity in the containment building, the density may increase and i
volume decrease during normal plant operation.
is senservative with respect to achieving a minimum require
]
}
Sufficient Tat is required to be available in MODES 1 because the RCs is at elevated temperature and pressure, pro,viding an 2, and 3, j
energy potential for a LOCA.
fcr the ability to control the pH of the recirculated coolant.The potential for a Ibc 3
2r it is discovered that the tsp in the containment building i
is not within limits, action must be taken to restore the tsp to within i
limits.
corrections may not be possible.During plant operation the sentainment suey is not asse
{
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is allowed for restoring the tsp j
within limits, where possible, beesuse 72 heuta is the same tima allowed for j
restoration of other ECC8 componenta. If the T8? cannot be restored within limits within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the plant must be brought to a MODE in which the LCO i
does not apply.
The specified Allowed outage Times for reaching NOT STANDSY
{
full power in an orderly manner and without challenging plant s j
l' The SR 4.5.2 2.a periodic determination of the voluna of TSP in
{
containment must be performed due to the possibility of leaking valves and 1
tsp during normal operation. components in the containment building that could cause A Frequency of 18 months is required,to determine visually that combined a minimum of 270 cubic feet is coritained in j
j the tsp baskets.
of tsp to adjust the pH of the post 14CA sump solution to a value a 7.0.T t-1 1
j The periodic verification is required overy is months, since access j
to the 787 baskets is only feasible during outages, and normal fuel cycles are scheduled for le months.
Operating superience has shown this surveillanea 4
Frequency acceptable due to the margin in the volume of TSP placed in the j
eentainment building.
4 4
ARXANsAs - UNIT 2 3 3/4 6-4 Amendment No. H,MS,W.194 1
i 3'
4
. ~,
CONTAINMENT SYSTEMS BASES The SR 4.6.2.2.b requirement to dissolve a representative sample of TSP in a sample of borated water provides assurance that the stored TSP will dissolve in borated water at the postulated post-LOCA temperatures.
Testing must be performed to ensure the solubility and buffering ability of the TSP after exposure to the containment environment. A representative sample of 3.00 1 0.05 grams of TSP from one of the baskets in c.ontainment is submerged in 1.0 i 0.01 liter of water at a boron concentration of 3000 1 30 ppm and at a temperature of 120 1 5'F.
The solution is allowed to stand for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> without agitation.
The liquid is then decanted from the solution and mixed, the temperature adjusted to 7712*F and the pH measured. At this point, the pH must be 2 7.0.
The representative sample weight is based on the minimum required TSP weight of 6804 kilograms, which at manufactured density corresponds to the minimum volume of 278 cubic ft, and assumed post LOCA borated water mass in the sump of approximately 5284102 lbm normalized to buffer a 1.0 liter sample.
The boron concentration of the test water is representative of the maximum possible boron concentration corresponding to the maximum possible post LOCA sump volume. Agitation of the test solution is prohibited, since an adequate standard for the agitation intensity cannot be specified.
The test time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is necessary to allow time for the dissolved TSP to naturally diffuse through the sample solution.
In the post LOCA containment sump, rapid mixing would occur, significantly decreasing the actual amount of time before the required pH is achieved.
This would ensure compliance with the Standard Review Plan requirement of a pH 2 7.0 by the onset of recirculation after a LOCA.
3/4.6.2.3 CONTAINMENT COOLING SYSTEM The OPERABILITY of the containment cooling system ensures that 1) the containment air temperature will be nmintained within limits during normal operation, and 2) adequate heat removal capacity is available when operated in conjunction with the containment spray systems during post-LOCA conditions.
The containment cooling system and the containment spray system are redundant to each other in providing post accident cooling of the containment atmosphere.
As a result of this redundancy in cooling capability, the allowable out-of-service time requirements for the containment cooling system have been appropriately adjusted.
However, the allowable out of service time requirements for the containment spray system have been maintained consistent with that assigned other inoperable ESF equipment since the containment spray system also provides a mechanism for removing Iodine from the containment atmosphere.
In addition of a biocide to the service water system is performed during containment cooler surveillance to prevent buildup of Asian clana in the coolers when service water is pumped through the cooling coils.
This is performed when service water temperature is between 60* F and 80' F since in this water temperature range Asian clams can spawn and produce larva which could pass through service water system strainers.
ARKANSAS - UNIT 2 B 3/4 6-5 Amendment No. %A,194
e l
CONTAIMMENT SYSTEMS BASES 3/4.6.3 CONTAINMENT ISOLATION VALVES j
r l
The OPERABILITY of the containment isolation valves ensures that the containment atmosphere will be isolated from the outside environment in the event of a release of radioactive material to the containment atmosphere or pressurization of the containment. Containment isolation within the time limits specified ensures that the release of radioactive material to the environment will be consistent with the assumptions used in I
the analyses for a LOCA: The containment isolation valves are listed in Procedure 2203.005.
The opening of locked or sealed closed manual and deactivated automatic containment isolation valves on an intermittent basis under administrative control includes the following considerations:
(1) stationing an operator, i
who is in constant communication with control room, at the valve controls, (2) instructing the operator to close these valves in an accident situation, and (3) assuring that environmental conditi'ons will not preclude access to close the valves and that this action will prevent the release of radioactivity outside containment.
3/4.6.4 COMBUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be l
available to maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions.
Either recombiner unit is capable of controlling the expected hydrogen generation associated with 1) l zirconium-water reactions, 2) radiolytic decomposition of water, and 3) corrosion of metal within containment.
These hydrogen control systems are consistent with the recommendations of Regulatory Guide 1.7 " Control of l
Combustible Gas Concentrations in Containment Following a LOCA", March 1971.
The containment recirculation units are provided to ensure adequate mixing of the containment atmosphere following a LOCA.
This mixing action will prevent localized accumulations of hydrogen from exceeding the flammable limit.
1 i
4 I
, UNIT 2 B 3/4 6-6 Amendment No.194 l
.-.