En tergy Entergy Nuclear Operations, Inc. Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Mike Bellamy Site Vice President March 27, 2003 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 SUBJECT: Entergy Nuclear Operations, Inc. Pilgrim Nuclear Power Station Docket 50-293 License No. DPR-35 Response to NRC Request for Additional Information Related to Technical Specification Changes to Post-Accident Monitoring Instrumentation Requirement REFERENCE: 1. Entergy letter to the NRC, 2.02.072, Request for Amendment to the Technical Specifications - Changes to Post-Accident Monitoring Instrumentation Requirements, dated August 19, 2002 2. Entergy letter to the NRC, 2.03.019, Request for Amendment to the Technical Specifications - Changes to Post-Accident Monitoring Instrumentation Requirements, dated February 14, 2003. LETTER NUMBER: 2.03.034 Dear Sir or Madam: Discussions with the NRC indicated that additional information was needed to complete their review of the proposed License Amendment submittal (Reference 1). Attached is the additional information requested. This response does not change the no significant hazard conclusions previously submitted in Entergy Letter 2.02.072, dated August 19, 2002. Should you have any questions or comments concerning this submittal, please contact Bryan Ford at (508) 830-8403. 2.03.034 D4& f
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Pilgrim, Response to NRC Request for Additional ... · The correct calibration frequency for the Suppression Chamber Water Level instrumentation is Once/6 Months, not Once/24 Months
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En tergy Entergy Nuclear Operations, Inc.Pilgrim Nuclear Power Station600 Rocky Hill RoadPlymouth, MA 02360
Mike BellamySite Vice President
March 27, 2003
U.S. Nuclear Regulatory CommissionAttn: Document Control DeskWashington, DC 20555
Response to NRC Request for Additional InformationRelated to Technical Specification Changes to Post-AccidentMonitoring Instrumentation Requirement
REFERENCE: 1. Entergy letter to the NRC, 2.02.072, Request for Amendment to theTechnical Specifications - Changes to Post-Accident MonitoringInstrumentation Requirements, dated August 19, 2002
2. Entergy letter to the NRC, 2.03.019, Request for Amendment to theTechnical Specifications - Changes to Post-Accident MonitoringInstrumentation Requirements, dated February 14, 2003.
LETTER NUMBER: 2.03.034
Dear Sir or Madam:
Discussions with the NRC indicated that additional information was needed to complete theirreview of the proposed License Amendment submittal (Reference 1). Attached is the additionalinformation requested.
This response does not change the no significant hazard conclusions previously submitted inEntergy Letter 2.02.072, dated August 19, 2002.
Should you have any questions or comments concerning this submittal, please contact BryanFord at (508) 830-8403.
2.03.034 D4& f
Entergy Nuclear Operations, Inc.Pilgrim Nuclear Power Station'
Letter Number: 2.03.034Page 2
I declqre under penalty of perjury that the foregoing is true and correct. Executed on the721.1 day of March 2003.
Sincerely,
Robert M. Bellamy
JRH/dd
Attachments: 1. Response to NRC Request for Additional Information (2 pages)2. Proposed Technical Specification and Bases Changes (Mark-up) (22 pages)
cc: Mr. Travis Tate, Project ManagerOffice of Nuclear Reactor RegulationMail Stop: 0-8B-1U.S. Nuclear Regulatory Commission1 White Flint North11555 Rockville PikeRockville, MD 20852
U.S. Nuclear Regulatory CommissionRegion 1475 Allendale RoadKing of Prussia, PA 19406
Senior Resident InspectorPilgrim Nuclear Power Station
Mr. Robert WalkerRadiation Control ProgramCommonwealth of MassachusettsExec Offices of Health & Human Services174 Portland StreetBoston, MA 02114
Mr. Steve McGrail, DirectorMass. Emergency Management Agency400 Worcester RoadP.O. Box 1496Framingham, MA 01702
2.03.034
ATTACHMENT 1
Response to NRC Request for Additional Information
Changes to Post-Accident Monitoring Instrumentation Requirements
2.03.034
Letter Number: 2.03.034Page 1 of 2
NRC Request 1:Please clarify the changes in titles for instruments referenced in 2.A.
ResponseTorus Pressure/Drywell Pressure was changed to Suppression Chamber Bottom PressureTorus Water Level was changed to Suppression Chamber Water LevelContainment Pressure (High Range) was changed to Drywell Pressure (Wide Range)Containment Pressure (Low Range) was changed to Drywell Pressure (Narrow Range)Containment High Radiation (Drywell) was changed to Drywell High Radiation
These changes were made for clarity and consistency with the standard specifications.
NRC Request 2Why was the Containment H2 Analyzer Function deleted from TS 3/4.7.A.7.c?
ResponseThe Containment H2 Analyzer Function was deleted from specification 3/4.7.A.7.c and added toTable 3/4.2.F to be more consistent with the standard specifications. It is merely a relocationfor consistency.
NRC Request 3The marked-up bases changes were not clearly identified as such.
ResponseThe markups for the conforming bases changes are included at the end of the marked-upspecification changes.
ResponseAs stated in Response to Request 3, the relocation of the Containment H2 Analyzer fromspecification 3/4.7.A.7.c was not a deletion of the function but a relocation to Table 3/4.2.F forconsistency. As stated in H, it is an editorial change. Any changes to the requirement arediscussed in other line items.
NRC Request 5Please clarify the revised page numbers associated with Table 3.2.F and Table 4.2.F.
ResponseThe page insert identification provided as part of the marked-up pages was chosen to associatethe revised information with the affected page rather than chronological changes. The revisedtable page will be the same initial number and the deleted pages will be so identified. Pages3/4.2-27, 3/4.2-28, and 3/4.2-37 will state: "This page is intentionally left blank."
NRC Request 6Why were notes 4-7 associated with Table 3.2.F deleted?
2.03.034
Letter Number: 2.03.034Page 2 of 2
ResponseNotes 5 and 7 were incorporated into the revised notes for Table 3.2.F. Notes 4, part of 5, and6 were deleted since they were no longer applicable.
NRC Request 7Please clarify the correct calibration frequency for Item 7, Suppression Chamber Water Level.Is it 6 months or 24 months?
ResponseThe correct calibration frequency for the Suppression Chamber Water Level instrumentation isOnce/6 Months, not Once/24 Months as was mistakenly shown on Table 4.2.F. The markuphas been corrected.
LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS
3.1 REACTOR PROTECTION SYSTEM 4.1 3/4.1-1BASES B3/4.1 -1
3.2 PROTECTIVE INSTRUMENTATION 4.2 3/4.2-1A. Primary Containment Isolation Functions A 3/4.2-1B. Core and Containment Cooling Systems B 3/4.2-1C. Control Rod Block Actuation C 3/4.2-2D. Radiation Monitoring Systems D 3/4.2-2E. Drywell Leak Detection *i t..forin E 3/4.2-3F. Sur'.'illaRnco InformationA6 Redou-ts- Po-stAcC-gdQ-vntAoy.11ir t F 3/4.2-3G. Recirculation PumpTrip/Alternate Rod IstrUrme~nt&± 6A G
Insertion 3/4.2-4H. Drywell Temperature H 3/4.2-5
BASES B314.2- 1
3.3 REACTIVITY CONTROL 4.3 3/4.3-1A. Reactivity Margin - Core Loading A 3/4.3-1B. Control Rod Operability B 3/4.3-2C. Scram Insertion Times C 3/4.3-7D. Control Rod Accumulator D 3/4.3-8E. Reactivity Anomalies E 3/4.3-10F. Rod Worth Minimizer (RWM) F
3/4.3-11G. Scram Discharge Volume G 3/4.3-12H. Rod Pattern Control H 3/4.3-13
BASES B3/4.3-1
3.4 STANDBY LIQUID CONTROL SYSTEM 4.4 3/4.4-1BASES B3/4.4- 1
3.5 CORE AND CONTAINMENT COOLING 4.5 3/4.5-1SYSTEMS
A. Core Spray and LPCI Systems A 3/4.5-1B. Containment Cooling System B 3/4.5-3C. HPCI System C 3/4.5-7D. Reactor Core Isolation Cooling (RCIC) System D 3/4.5-8E. Automatic Depressurization System (ADS) E 3/4.5-9F. Minimum Low Pressure Cooling and Diesel F
Generator Availability 3/4.5-10G. (Deleted) G 3/4.5-11H. Maintenance of Filled Discharge Pipe H 3/4.5-12
BASES B3/4.5-1
A
PNPS i Amendment No.-18&
LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT
3.2 PROTECTIVE INSTRUMENTATION (Cont)
j)E. Drywell Leak Detection
The limiting conditions ofoperation for the instrumentationthat monitors drywell leakdetection are given in Section3.6.C.
4.2 PROTECTIVE INSTRUMENTATION (Cont)
E. Drywell Leak Detection
Instrumentation shall befunctionally tested, calibratedand checked as indicated inSection 4.6.C.
/)
Amendment No. 89, 13/ 3/4.2 -3
INSERT 3/4.2-3A
F. Post-Accident Monitoring Instrumentation
During the RUN MODE and the STARTUPMODE the limiting conditions for theinstrumentation that provides post-accidentmonitoring are given in Table 3.2.F.
F. Post-Accident Monitoring Instrumentation
Instrumentation shall be calibrated andchecked as indicated in Table 4.2.F.
PNPS
TABLE 3.2.F
SURVEILLANCE INSTRUMENTATION
# ofOperable Inst ent Insi
Channels
2 640
2 640
2 TRlTRl
2 TRlTl-9
2 TRtTl-9
2 LR-LR-
1 NA
trument # Parameter
B Reactor Water Level
\BReactor Pressure1-25A & B
J-9044J-9045
J-90449019
J-90459018
50385049
Type Indication and Range Notes
Indicator 0-60" (1) (2) (3)
Indicator 0-1200 psig (1) (2) (3)
Recorder 0-80 psia (1) (2) (3)
Recorder, Indicator 0-400°F (1) (2) (3)
Resder.lIndicator 0-400°F (1) (2) (3)
Dr
Drywell Temperature
Suppression Chamber AirTemperature
Suppression Chamber WaterLevel
(1) (2) (3)
Neutron Monitoring SRM, IRM, LPRM0 to 100% power
\_ , 9,f -- 1Y1d
(1) (2)
Amendment No. 31, 48, 83, 18C 3/4.2-25 1
INSERT 3/4.2-25A
PNPS
TABLE 3.2.F
Post-Accident Monitoring Instrumentation
1.
2.
3.
4.
5.
6.
7
8.
9.
10.
11.
Function
Reactor Water Level
Reactor Pressure
Drywell Temperature
Neutron Monitoring
Suppression Chamber Water Temperature
Suppression Chamber Bottom Pressure
Suppression Chamber Water Level
Drywell Pressure (Wide Range)
Drywell Pressure (Narrow Range)
Drywell High Radiation
Containment H2 Analyzer
Minimum # of OperableInstrument Channels
2
2
2
2
2
2
2
2
2
2
2
Notes
(1) (2)
(1) (2)
(1) (2)
(1) (2)
(1) (2)
(1) (2)
(1) (2)
(1) (2)
(1) (2)
(1) (3)
(1) (4)
Amendment No. 8 3,139314.2-25
I "
I
'- t PS
TAbLc 3.2.F (Cont)
Minimum # of Operable Instrument Parameter Type Indication Notesnels Instrument and Range
Tl-5021-2A Suppression Chamber Indicator/TRU-5021-1A Water Temperature Multipoint Recorder (1) (2) (3) (4)
30-230OF (Bulk)
B Suppression Chamber Indicator/B Water Temperature Multipoint Recorder (1) (2) (3) (4)
LI-1001-604B 8LR-1001-604B Torus Water Level Indicator/Multipoint (1) (2) (3) (4)
(Wide Range) Recorder 0-300" H20
Amendment No. 56, 83,172 3/4.2-26
INSERT 3/4.2-26A
Notes for Table 3.2.F
(1) With less than the minimum number of instrument channels, restore the inoperablechannel(s) within 30 days. If the inoperable channel(s) are not restored, prepareand submit a special report to the Commission within 14 days of the event outliningthe action taken, the cause of the inoperability and the plans and schedule forrestoring the channels to operable status.
(2) With the instrument channel(s) providing no indication to the control room, restorethe indication to the control room within 7 days. If the indication is not restored, anorderly shutdown shall be initiated and the reactor shall be in the Hot ShutdownCondition within 12 hours.
(3) With the instrument channel(s) providing no indication to the control room, restorethe indication to the control room within 7 days. If the indication is not restored,prepare and submit a special report to the Commission within 14 days of the eventoutlining the action taken, the cause of the inoperability and the plans and schedulefor restoring the channels to operable status.
(4) With the instrument channel providing no indication to the control room, restore theindication to the control room within 72 hours. If the indication is not restored, anorderly shutdown shall be initiated and the reactor shall be in the Hot ShutdownCondition within 12 hours.
Amendment No. -69 1/9 314.2-26
PNPSTABLE 3.2.F (Cont)
SURVEILLANCE INSTRUMENTATION
Minimum # ofOperable Instrument
Channels
2
2
2
1
1
Type IndicationInstrujftt Parameter and Range Notes
(RIT 1001-606A Containment High Radiation M tor/Multipoint(RIT 1001-606B (Drywell) Reco r (4(RR 1001-606A I to 1(RR 1001-606B I
RI 1001-609 Reactor Building Vent Indicator/Multipot (4) (7)RR 1001-608 Recorder
l0- to 104 R/hr
RI 1001-608 Main Stack Vent Indicator/Multipoint (4) (RR 1001-608 Recorder
10-1 to 104 R/hr
RI 1001-610 Turbine Building Vent Indicator/Multipoint (4) (7)RR 1001-608 Recorder
1
10- to 104 R/hr
Amendment No. 56, 83, 14L73 3/4.2 -2 7
Insert Page 3/4.2-27A
This page is intentionally left blank
Amendment No. 8, 3142314.2-27
V TS FOR TABLE 3.2.F
( With less than the minim numer of instrument channels, restore the
inoperable channel(s) within 30 days.
(2) ith the instrument channel(s) providing no indication to the control room,re tore the indication to the control room within seven days.
(3) If t e requirements of notes (1) or (2) cannot be met, an orderly shutdown
shall e initiated and the reactor shall be in the Cold Shutdown Condition
within hours.
(4) These surv illance instruments are considered to be redundant to each other.
(5) At a minimum , the primary or back-up* parameter indicators shall be operable
for each valve hen the valves are required to be operable. With both primaryand backup* inst ument channels inoperable either return one (1) channel to
operable status we hin 31 days or be in a shutdown mode within 24 hours.
The following instr ents are associated with the safety/relief and safety
valves:
Primar SecondaryValve Acoustic MoniTail Pipe Temperature
13) Torus Water Level (Wide Ra Each refueling outage Once every 30 days
14) Containment Pressure Each refueling outage Once every 30 days
15) Containment High Radiation e/Operating cycle Once every 30 days
16) Reactor Building Vent Radiation Monitor Once/Oper Ccle Once every 30 days
17) Main Stack Vent Radiation Monitor Once/Operating Cycle Once every 30 days
18) Turbine Building Vent Radiation Monitor Once/Operating Cycle cvery 30 days
Amenmt s /4io -Amendment No.42,4-8448- 3/4.2-38
Insert page 3/4.2-38A
This page is intentionally left blank
Amendment No. 89, 4 39 314.2-38
MnTVR VnP TABTLES A 9 A THROIUG 4 -L9 -G
1. Initially once per month until exposure hours (M as defined on Figure 4.1.1)is 2.0 x 105; thereafter, according to Figure 4.1.1 with an interval not less
than one month nor more than three months.
2. Functional tests, calibrations and instrument checks are not required when
these instruments are not required to be operable or are tripped. Functional
tests shall be performed before each startupwith a required frequency not to
;Cexceed once er alibrations of IRMs and SRMs shall be performed----_
ot t exceed oncek. nstrument checks shall be performed at least
once per day during those periods when the instruments are required to be
operable.
3. s instrumentation is excepted from the functional tFi.T
functional njecting a simulated electrical signal intoO e measurement channel.
4. Simulated automatic actuation shall be performed once each operating cycle.
Where possible, all logic system functional tests will be performed using the
test jacks.
5. Reactor low water level and high drywell pressure are not included on Table
4.2.A since they are tested on Tables 4.1.1 and 4.1.2.
6. The logic system functional tests shall include a calibration of time delay
relays and timers necessary for proper functioning of the trip systems.
7. Calibration of analog trip units will be performed concurrent with functional
testing. The functional test will consist of injecting a simulated
electrical signal into the measurement channel. Calibration of associated
analog transmitters will be performed each refueling outage.
-3
Amendment No. 42, 99, 110 147, 154i 3/4.2-41
LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS
3.7 CONTAINMENT SYSTEMS (Cont)
) A. Primarv Containment (Cont)
i 7. Containment Atmosphere Dilution
4.7 CONTAINMENT SYSTEMS (Cont)
A. Primary Containment (Cont)
7. Containment Atmosphere Dilution
a. Within the 24-hour periodafter placing the reactor inthe Run Mode the Post-LOCAContainment AtmosphereDilution System must beoperable and capable ofsupplying nitrogen to thecontainment for atmospheredilution. If thisspecification cannot be met,the system must be restoredto an operable conditionwithin 30 days or thereactor must be at least inHot Shutdown within 12hours.
b. Within the 24-hour period -after placing the reactor inthe Run Mode, the NitrogenStorage Tank shall contain aminimum of 1500 gallons ofliquid N2. If thisspecification cannot be metthe minimum volume will berestored within 30 days orthe reactor must be in atleast Hot Shutdown within 12hours.
> Tx here are 2 H2 analyzersvailable to serve thedyell.
With onulH2 analyzeroperable, actor operationis allowed fo up to 7 days.If the inoperab analyzeris not made fully erablewithin 7 days, the re torshall be in a least HotShutdown within the next 1hours.
a. The post-LOCA containmentatmosphere dilution systemshall be functionally testedonce per operating cycle.
b. The level in the liquid N2storage tank shall berecorded weekly.
The H2 analyzers shall beteste erability once
\ per month andl calibrated once per 6
months./
d. Once per month each manualor power operated valve in
- the CAD system flow path notlocked, sealed or otherwisesecured in position shall beobserved and recorded to bein its correct position.
)
envis ion 177)Amendment No. Ail 3/4.7-10
LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS
CONTAINMENT SYSTEMS (Cont.)
(Cont.With n1alyzer operable, reactoroperation is allowL uto 48 hours: Ifone of the inoperable analyz os t madefully operable within 48 hours, the reactoshall be in at least Hot Shutdown within thenext 12 hoLjrs. /
4.7 CONTAINMENT SYSTEMS (Cont.)
B. Standby Gas Treatment System andControl Room Hiqh Efficiency Air FiltrationSystem
1. Standby Gas Treatment System1. Standby Gas Treatment System
a. Except as specified in 3.7.B.1.c or3.7.B.1.e below, both trains of thestandby gas treatment shall beoperable when in the Run, Startup,and Hot Shutdown MODES, duringmovement of irradiated fuelassemblies in the secondarycontainment, and during movementof new fuel over the spent fuel pool,and during CORE ALTERATIONS,and during operations with apotential for draining the reactorvessel (OPDRVs),
or
the reactor shall be in coldshutdown within the next 36 hours.
b. 1. The results of the in-place coldDOP tests on HEPA filters shallshow >99% DOP removal. Theresults of halogenatedhydrocarbon tests on charcoaladsorber banks shall show>99.9% halogenatedhydrocarbon removal.
a. 1. At least once per operating cycle,it shall be demonstrated thatpressure drop across thecombined high efficiency filters andcharcoal adsorber banks is lessthan 8 inches of water at 4000 cfm.
2. At least once per operating cycle,demonstrate that the inlet heaterson each train are operable and arecapable of an output of at least 20kW.
3. The tests and analysis ofSpecification 3.7.B.1.b. shall beperformed at least once peroperating cycle or followingpainting, fire or chemical release inany ventilation zonecommunicating with the systemwhile the system is operating thatcould contaminate the HEPA filtersor charcoal adsorbers.
4. At least once per operating cycle,automatic initiation of
Trip settings of < 100 mr/hr for the monitors in the refueling areaventilation exhaust ducts are based upon initiating normal ventilation
isolation and standby gas treatment system operation so that none of theactivity released during the refueling accident leaves the Reactor Buildingvia the normal ventilation path but rather all the activity is processed by
the standby gas treatment system.
For most parameters monitored, as listed in Table 3.2.F, there are two (2)channels of instrumentation. By comparing readings between these two (2)channels, a near continuous surveillance of instrument performance isavailable. Meaningful deviation in comparative readings of these instrumentswill initiate an early recalibration, thereby maintaining the quality of the
instrument readings.
The Safety - Saf ye position indication instrumentation providesthe operator with information on selecte pnitor and
^iT ' ssess these variables during and following an accident.
rIn response to NUREG-0737, modifications were made to the ADS logic to extendautomatic ADS operation to a class of transients that involve slowly
uncovering the core without depressurizing the vessel or pressurizing thedrywell. These transients were analyzed assuming no high pressure injectionsystems (feedwater, HPCI or RCIC) are available. Only ADS is consideredavailable to depressurize the vessel, permitting operation of LPCI. The
transients generally involve pipe breaks outside containment. Automatic ADSwould not occur on low water level because high drywell pressure would not bepresent and ADS logic has a high drywell pressure permissive. Themodification added a timer to the ADS logic which bypasses the high drywellpressure permissive, and a manual inhibit switch which allows the operator toinhibit automatic ADS initiation for events where automatic initiation is notdesirable.
An analysis was performed to determine an upper time limit on the bypasstimer. The goal was to ensure ADS is automatically initiated in time toprevent peak clad temperature (PCT) from exceeding 1500'F for a limitingbreak, which was determined to be a Reactor Water Cleanup line break. Theanalysis concluded that there are 18 minutes between the low water level
initiation of the timer and the heatup of the cladding to the limit. Sincethe logic includes a 2 minute delay already, the bypass timer upper limit cannot be more than 16 minutes, which provides a conservative margin for PCT andallows sufficient time for operator intervention if required. A minimum timedelay is incorporated to allow RPV water level to recover, resetting the timerand preventing depressurization. The choice of a timer setting of 11 minutesplaces the setting in the middle and provides maximum tolerance from either
limit. (Reference: GE Report "Bypass Timer Calculation for the ADS/ECCSModification for Pilgrim Station" December 16, 1986).
Revision B
2 = -9iEBB 39 eB3/4.2-5
INSERT B3/4.2-5A
The following are the instruments which meet the quality requirements of Regulatory Guide 1.97 andcan be credited to meet the operability requirements of Specification 3/4.2.F. Two channels ofindication in the control room from the below list must be available to meet the Specificationrequirements.
-
Specification 314.2.F Function1. Reactor Water Level
Regulatory Guide 1.97 Instruments
LI 263-1O0A, LI 263-106A, LR 1001 -604ALI 263-1OOB, LI 263-106B, LR 1001-604BLI 1001-650A, LI 1001-650B
) wetwell pressure differential to keep the suppression chamber downcomer legs
clear of water significantly reduced suppression chamber post LOCA
hydrodynamic loads. A pressure of 1.17 psid is required to sufficiently clear
the water legs of the downcomers without bubbling nitrogen into thesuppression chamber at the 3.00 ft. downcomer submergence which corresponds to
approximately 84,000 ft.3 of water. Maximum downcomer submergence is 3.25 ft.at operating suppression chamber water level. The above pressure differential
and submergence number are used in the Pilgrim I Plant Unique Analysis.
Post LOCA Atmosphere Dilution
In order to ensure that the containment atmosphere remains inerted, i.e. the
oxygen-hydrogen mixture below the flammable limit, the capability to inject
nitrogen into the containment after a LOCA is provided. A minimum of 1500
gallons of liquid N2 in the storage tank assures that a three-day supply of N2for post-LOCA containment inerting is available. Since the inerting makeup
system is continually functioning, no periodic testing of the system isrequired.
The Post-LOCA Containment Atmospheric Dilution (CAD) System is designed to
meet the requirements of AEC Regulatory Guides 1.3, 1.7 andT1.29, ASME SectionIII, Class 2 (except for code stamping) and seismic Class I as defined in'the
PNPS FSAR.
In summary, the limiting criteria are:
1. Maintain hydrogen concentration in the containment during post-LOCAconditions to less than 4%.
2. Limit the buildup in the containment pressure due to nitrogen additionto less than 28 psig.
3. To limit the offsite dose due to containment venting (for pressurecontrol) to less than 300 Rem to the thyroid.
By maintaining at least a 3-day supply of N2 on site there will be sufficient
time after the occurrence of a LOCA for obtaining additional nitrogen supply
> from local commercial sources.(') The system design contains sufficient
redundancy to ensure its reliability. Thus, it is sufficient to test theuab-i4 y-of who~~le s stem once e -operating cycle he 2 analz
will provide redundancy for the drywell ize.,lere a ana yzers for
the Unit. By permitting react days with one of the two H2analyzers oency of analyzing capability will be maintained
ot imposing an immediate interruption in plant operation. Monthly
(1) As listed in Pilgrim Nuclear Power Station Procedure No. 5.4.6 "PostAccident Venting".
Revisioneiidndment No. 55,- - B3/4.7-8
BASES:
3/4.7 CONTAINMEN SYSEM (Cn
) " aqlyzrs using H2 will be adequate to ensure the system's readinessbecause of the design. b azlzers are normally not in operation there will
Q be little deterioration due to use. In ord-r6-detemwHzconcentration, the)analyzers must be warmed up 6 hours prior to putting into se: fis acceptable for accident conditions because a 4OX H2 level will not be reahdI
tth drwel util16 ous flloin th acidnt.[ Detnitrogen addition, therincrease with time. Under the worst
expected conditions the containment pressure will reach 28 psig in approximately45 days. If and when that pressure is reached, venting from the containment shallbe manually initiated per the requirements of 10CFR50.44. The venting path willbe through the Standby Gas Treatment system in order to minimize the off sitedose.
B.1 Standby Gas Treatment System
The Standby Gas-Treatment System is designed to filter and exhaust the reactorbuilding atmosphere to the stack during secondary containment isolationconditions. Upon containment isolation, both standby gas treatment fans aredesigned to start to bring the reactor building pressure negative so that all leakageshould be in leakage. After a preset time delay, the standby fan automaticallyshuts down so the reactor building pressure is maintained approximately 1/4 inch ofwater negative. Should one system fail to start, the redundant system is designedto start automatically. Each of the two trains has 100% capacity.
High Efficiency Particulate Air (HEPA) filters are installed before and after thecharcoal adsorbers to minimize potential release of particulates to the environmentand to prevent clogging of the iodine adsorbers. The charcoal adsorbers areinstalled to reduce the potential release of radioiodine to the environment. The in-place test results should indicate a system leak tightness of less than 1 percentbypass leakage for the charcoal adsorbers and a HEPA filter efficiency of at least99 percent removal of cold DOP particulates. The laboratory carbon sample testresults should indicate a methyl iodide removal efficiency of at least 95 percent forexpected accident conditions. The specified efficiencies for the charcoal andparticulate filters is sufficient to preclude exceeding 10CFR100 guidelines for theaccidents analyzed. The analysis of the loss of coolant accident assumed acharcoal adsorber efficiency of 95% and TID 14844 fission product source terms,hence, installing two banks of adsorbers and filters in each train provides adequatemargin. A 20 kW heater maintains relative humidity below 70% in order to ensurethe efficient removal of methyl iodide on the impregnated charcoal adsorbers.Considering the relative simplicity of the heating circuit, the test frequency ofonce/operating cycle is adequate to demonstrate operability.
Air flow through the filters and charcoal adsorbers for 15 minutes each monthassures operability of the system. Since the system heaters are Iautomatically controlled, the air flowing through the filters and adsorbers willbe <70% relative humidity and will have the desired drying effect. _