Text

Proposed Tech Specs,Representing Revs to TS Tables 3.1.1, 3.2.1,3.2.2,3.2.3,Section 3.2.D.2, Air Ejector Off-Gas Sys & Section 3.7/4.7.C, Secondary Containment
	ML20136B343
Person / Time
Site:	Millstone
Issue date:	03/06/1997
From:	; NORTHEAST NUCLEAR ENERGY CO.
To:	;
Shared Package
ML20136B320	List: B16312, Application for Amend to License DPR-21,by Incorporating Changes Representing Revs to TS Tables 3.1.1,3.2.1,3.2.2, 3.2.3,Section 3.2.D.2 & Section 3.7/4.7.C; ML20136B343;
References
	NUDOCS 9703100243
	Download: ML20136B343 (36)
	v • d • e

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Sept. 25 .993 TABLE 3. .. (Contir.ned)

REACTOR FROTECTION SYSTEM (SCRAM) INSTRUMENTATION REQUIREMENTS .

l Minimum Number of Operable Modes in which Function j Inst. Channels Trip Function Trip Level Setting Must Be coerable Action

t per Trip (1) REFUEL / STARTUP/ HOT i System i SHUTDOWN (8,11) stale 8Y RUN 2 Turbine Condenser Low 2 23 in. Hg. Vacuum X (3) X (3) X A.or C Vacuum If 4 (6) Main Steamline Isolation s 107 Valve Closure X (3) .X (3) X - A or C t Valve Closure I

2 Turbine Control Valve See Section 2.1.2 F X (4) X (4) X (4) A or C.

Fast Closure . r .

2 Turbine Stop Valve s 107. Valve Closure X(4) X (4) X (4) A or C t

Notes: 1. shall be two operable or tripped trip systems for each function. .

2. Permissible to bypass, with control rod block, for reactor protection system reset in REFUEL and SHUTDOWN positions of the reactor mode switch.

3. Bypassed when reactor pressure is < 600 psig.

4. Bypassed when first stage turbine pressure is less than that which corresponds to 507, rated reactor thermal power.

r A A)

Millstone Unit 1 3/4 1-4 Amendment No. JJ, JJ, JJ, JJ 64 eene 9703100243 DR 970306 ADOCK 05000245 PDR

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l U.S. Nuclear Regulatory Commission B16312\ Attachment 4\Page 1

. INSERT A

. (page 3/41-4)

A channel may be placed in an inoperable status for up to two hours during periods of 4

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required surveillance without placing the Trip System in the tripped condition provided the associated Trip Function maintains trip capability. Otherwise, there 1

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TABLE 3.2.1 sept. 29 .993*

INSTRUMENTATION THAT INITIATES PRIMARY CONTAINNENT IS01.

Minimum Number of Operable Instrument Channels Per Trip System f21 -

lastrumenta Trin Level settina 2

t gggggy, !

Reacter Low Water 2

Reactor Low Low Water 1127 inches above top ef active fuel A 2 High Dryweil PMssure 79(+4-0 2

i 2 psig) inches above top of active fuel. A (5) High Flow Main Steamitne .A 2 of 4 in e of High Temperature Matr. 11205 ef rated steam flow B 2 subchannels Steamline Tunnel 2 Low pressure Main s 200*F B

1 825 psig 2

Steamitnes High Flow Isolation 164 inches 1 trip setting 8

'(i Condenser Line C -

on steam ilne) 1150 inches (w.ater differential 44 inches 1 trip setting

on water side) 1 35 inches (w.ater differential t h M primary containment integrity is required, there shall be two operable or trip for each position. function, except for low pressure main steamitne which only need be available in the RUN lAction:Per each steamitne.

If the /trst column cianot be met for one of the trip systese, that trip system shall be tripped.

If the first column cannet be met for both trip system, the approprkte .,dions listed below shall be taken:

A. ,

B. Initiate an orderly shutdown and have reactor la cold shutdown condities in 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

C. CloseInitiate an orderly load reduction and have reactor in HDT STANDBY within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

, isolation valves in isolation condenser system. '

(4)

May be bypassed when necessary by closing the manual tastrument tselation valve for PS-1621, A thro -

D, during perging for containment inerting or deinerting.

(5)

Mlatmum number of operable instrument channels per trty system requirement does not have to be met for a steamIfne if both containment isolation valves in the Ifne are closed.

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r ' stone Unit No. I 2-2 Amendment No ,- JJ, JJ 64 t

U.S. Nuclear Regulatory Commission B16312\ Attachment 4\Page 2 INSERT B I (page 3/4 2-2)

A channel may be placed in an inoperable status for up to two hours during periods of required surveillance without placing the Trip System in the tripped condition provided the associated function maintains trip capability. Otherwise, whenever l

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l TAst.E 3.2.2 (Continued)

{ INSTRONDITATION THAT INITIATES AND CONTR0t.$ THE DIUtGUICY CORE CMINE SYSTDIS E

NOTE:

M I 1)

VMhecolumn cannot first be column met for both cannot trfp systems, beimmediately met forinitiate oneanof thes triptripped.

orderly systems, that system If the first onditions.

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U.S. Nuclear Regulatory Commission B16312%ttachment 4\Page 3 INSERT C (page 3/4 2-6)

A channel may be placed in an inoperable status for up to two hours during periods of required surveillance without placing the Trip System in the tripped condition provided the associated Trip Function maintains trip capability. Otherwise, if l

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3/30/e4 ,

TABLE 3.2.3(Continued)

.. IltsTRINIEIITATION TIIRT INITIATES ROD BLOUC _

Inset D] .

5R1818 (1) & the STARTUP/IIST STAND 8Y and Rull positions of the Ileacter liede selector Swttch, there shall be two er tel trip systems for each f SIBt red b1 Ilgt dounscale are not functlenleexcept the scram discharge volume - water level high and in the RINI positten and APIst dounscale need net be

' able in the 5 T STAleBY mode. I l-is conditten may exist for up to seven days provided that dortthe first thatceluun cannot time the be met operable for one system is of the two tr!i i

if this c tttan lasts lenger than seven days, the '

functlenally tested immediately system shall be tripped. If the first column and daily cannet thereafter;be met for both trty systems, the syste ,

tripped. l (2) W is the rectrculatten flew required to achieve rated core flev expressed in percent.

(3) 1851 dounseale may be bypassed when it is en its lowest range.

(4) This functlen may be bypassed when the count rate is 2100 cps or when all Ilgt range switches are above i posittaa 2.

(5) One of these trips may be bypassed. The slet functten may be bypassed, in the higher 1851 ranges, when -

the IIst upscale red block 1s operable.

(6) The trts may be bypassed when the reacter power is 130K of rated. A ROft channel will be constsered l inoperable if there are less than half the total nether of normal inputs from any LPl56 level. ;

(7) There must be a total of at least four (4) operable er operating APlWI channels. lt (8) For the STARTUp/IIOT STAleBY and 11011 posittens of the Reacter liede Selector Switch, there shall be one (1) scram discharge volume - water level ht instrument per instrument volume tank required to be operable. If i either of the instruments become inoper le, a red block shall be inttfated within one hour. ;

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'jstoneUnitI _

3/4 2-8 ndment flo.73

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a U.S. Nucisar Regulatory Commission B16312\ Attachment 4\Page 4 INSERT D l

(page 3/4 2-8) j A channel may be placed in an inoperable status for up to two hours during periods of !

required surveillance without placing the Trip System in the tripped condition provided I the associated function maintains trip capability. Otherwise, for l

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3 LIMITINGCofCITIONFORdptRATION f

i 3.2 PACTECTIVE INSTRUMENTAT!0N i

i C.2. The sinfaua number of operabb instrument channels specified in i Table 3.2.3 for the Rad Slot Monitor may be reduced by one for

{ maintenance any 30 day period. and/or testing for periods no* in excess of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months in D. Air Eieeter off-tar System ;

' 1.

i Except as specified in 3.2.0.2 below, both air ejector off-gas system radiation monitors shall be operable during reactor power i operatten. The trip settings for the monitors shall be set at a

! value not to exceed the equivalent of the instantaneous stack ;

i release limit specified in Specification 3.8. The time delay !

j valve shall not exceed 15 minutes. setting for closure of the steaa i

2.

g and after the date that one of the two air ejector off-gas systea radiation monitors is made or found to be inoperable, reactor provided sooner made operable.

the inoperable monitor is tripped, unless such 2

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peneter Buildino Ventilation fselatten. steam Tunnel Ventilation Isolation and Standby Gas Treatment System Initiation i

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duct radiation monitors, two refueling floor radiation m j

whenever secondary containment integrity is required.two s i 2.

One of the two reactor building ventilation duct radiation sonitors, one of the two refueling floor radiation monitors, and one of the two hrs. tunnel ventilation radiation monitors may be inoperable for 24 steaa If it is not restored to service in this time, tae reactor building ventilation systen and steam tunnel ventilation system shall be isolated and the standby gas treatment operated until repairs are complete or until secondary containment integrity is not required.

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) The radiation monitors shall be set to trip as follows:

i a.

Ventilation duct - 11 ar/hr.

t' b.

Refueling floor - 100 ar/hr.

1 c.

Steaa tunnel ventilation - 50 ar/hr.

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.M.i.llstone Unit 1 3/4 2-12 Amendment No. J. JJ, M,98

1 U.S. Nuclear Regulatory Commission B16312%ttachment 4\Page 5 s

i INSERT E l (page 3/4 2-12) i One air ejector off-gas system radiation monitor may be placed in an inoperable status :

i for up to two hours during periods of required surveillance without placing the Trip System in the tripped condition. Otherwise, from l

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LIMITING CONDITION FOR OPSATION l

3.7 CONTAlfetENT SYSTDts

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j Secondary containment integrity, as defined in Section 1, shall be OPERABLE:

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j a. When moving the fuel cask, irradiated fuel or other loads in i .

i containment which have the potential for causing a

! significant release of fission products.

i b. When perfoming CORE ALTERATIONS or operations with a potential for draining the reactor vessel when the vessel 1

contains irradiated fuel.

c. When in RUN, STARTUP/ HOT STAND 8Y or H0T SHUTDOWN. i

2. Ulf t;.. .;~ .. .......; L n t , i - d ut', ... - - f 'M ~+ 4 wi + 4 = =

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SURVEILLANCE REQUIREMDITS MIaad b

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4.7 CONTAINMENT SYSTEMS 1 l l C. Secondary containment i

j 1. Secondary containment surveillance shall be perfoneed as indicated i below:

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a. A secondary containment capability test shall be conducted l after isolating the reactor building and placin i

gas treatment system filter train in operation.gSuch eithertests standby

! shall demonstrate the capability of the secondary containment to maintain a 1/4 inch of water vacuum with a filter train flow rate of not more than 1100 sefa. Secondary containment capability shall be demonstrated at three or more points within the containment prior to fuel movement and may be demonstrated

(

I up to 10 days prior to fuel movement. Secondary containment j capability need not be demonstrated more than once per operat-ing cycle unless damage or modifications to the secondary containment have violated the integrity of the pressure

{ retaining boundary of that structure.

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! Ni11 stone Unit 1 3/4713 0245 Amendment No. J. N.98 i

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I U.S. Nucinar Regulatory Commission B16312\ Attachment 4\Page 6 INSERT F (page 3/4 7-13) l If the above cannot be met:

a. immediately suspend the activities listed in 3.7.C.1.a and 3.7.C.1.b; and

b. when in RUN, STARTUP/ HOT STANDBY, or HOT SHUTDOWN, restore secondary containment to OPERABLE status within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months or establish, within the succeeding 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , conditions where secondary containment integrity is not required.

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INSERT G I (page 3/4 7-13)

b. At least once a month, verify at least one door in each secondary containment ,

l access opening is closed. l l

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. ., Jtnuary 13, l'992

3.1 REACTOR PROTECTION SYSTEM BASES f

b

l l The reactor protection system automatically initiates a reactor scram to: '

l 1. preserve the integrity of the fuel cladding; 1

2. preserve the integrity c the primary system barrier; and

3. minimize the energy which must be absorbed, and prevent criticality

following a loss of coolant accident.

! These specifications provide the limiting conditions for operation i necessary to preserve the ability of the system to tolerate single failures and t still perform its intended function even during periods when instrument

channels may be out of service because of maintenance. When necessary, one

' channel may be made inoperable for brief intervals to conduct required functional tests and calibrations. *--(Is+ H)

The reactor protection system is of the dual channel type. Ref. ,

l Section 7.2 of the UFSAR. The system is made up of two independent logic !

I channels, each having two subchannels of tripping devices. Each subchannel l has an input from at least one independent sensor monitoring each of the

critical parametars.

! The outputs of the subchannels are combined in a 1 out of 2 logic; i.e., l an input signal on either one or both of the subchannels will cause a trip ,

system trip. The outputs of the trip systems are arranged so that a trip on ,

both channels is required to produce a reactor scram.

This system meets the requirements of the proposed IEEE Standard for Nuclear Power Plant Protection Systems issued September 13, 1966. The system has a reliability greater than that of a 2 out of 3 system and somewhat less than that of a 1 out of 2 system.

With the exception of the Average Power Range Monitor (APRM), Intermediate Range Monitor (IRM) channels, Main Steam Isolation Valve Closure, and Turbine Stop Valve Closure, each subchannel' has one instrument channel. When the minimum condition for operation on the number of operable instrument channels per untripped protection logic channel is met or if it cannot be met and the affected protection trip system is placed in a tripped condition, the effectiveness of the protection system is preserved; i.e., the system can tolerate a single failure and still perform its intended function of scramming the reactor. Three APRM instrument channels are provided for each protection trip system.

APRMs #1 and #3 operate contacts in a logic subchannel and APRMs #2 and

3 operate contacts in the other logic subchenel.

APRMs #4, f 5 and #6 are arranged similarly in the other protection trip system. Each protection trip system has one more APRM than is necessary to -

meet the minimum number required per channel. This allows the bypassing of one APRM per protection trip system for maintenance, testing or calibration, l

Millstone Unit 1 B 3/4 1-2 Amendment No. 55 ti o n

i U.S. Nuclear Regulatory Commission B16312\ Attachment 4\Page 7 INSERT H (page B 3/41-2)

Entry into associated action statements may be delayed for up to two hours provided the associated trip function maintains trip capability. A two-hour allowance for testing is judged acceptable based upon:

a) Remaining capability to trip. Testing of one sensor does not render the trip system inoperable, but rather, simply increases the single failure vulnerability of one trip function in one channel. Inoperabilities affecting diverse trip functions would require multiple failures.

b) Diversity of sensors available to provide the trip signals. Surveillance testing is not performed on multiple variables' sensors simultaneously; so other trip functions either remain operable or were previously declared inoperable and placed in a tripped condition.

c) Low likelihood of an event requiring the initiation of a scram during this time frame. !

d) Reasonable test interval. The two-hour test duration provides a reasonable amount of time for testing without placing undo time ccqstraints on personnel. j e) The two-hour time intervalis consistent with GE BWR Standard Technical l Specifications (NUREG-0123).

f) Two hours represents one-half of the required action completion time (four hours) I associated with an inoperable RPS trip function. l If it is discovered that an instrument channel cannot meet the surveillance requirement, the instrument channel shall be declared inoperable.

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Jasunry 13, 1992 l

l 3.2, PROTECTIVE INSTRUMENTATION ,

BASES i In addition to reactor protection instrumentation which initiaties a <

l reactor scram, protective instrumentation has been provided which initiates )

action to mitigate the consequences of accidents which are t yond the operator's ability to control or terminates operator errors Afore they result l in serious consequences. This set of specifications provides the limiting l conditions of operation for the primary system isolation function, initiation l of the emergency core cooling system, control rod block, and standby gas treatment systems. The objectives of the specifications are to assure the effectiveness of the protective instrumentation, when required, by preserving its capability to tolerate a signal failure of any component of such systems i even during periods when portions of such systems are out of service for maintenance. When necessary, one channel may be made inoperable for brief l intervals to conduct required functional tests and calibrations and to i

prescribe the trip settings required to assure adequate performance. dued I) l Isolation valves are installed in those lines that penetrate the primary l l containment and must be isolated during a loss of coolant accident so that the radiation dose limits are not exceeded during an accident condition. Actua-tion of these valves is initiated by protective instrumentation shown in Table

! 3.2.1 which senses the conditions for which isolation is' required. Such instrumentation must be available whenever primary containment integrity is '

required. The objective is to isolate the primary containment so that the l

guideline values of 10 CFR 100 are not exceeded during an accident.

I' The instrumentation which initiates primary system isolation is connected n a dual bus arrangement. Thus, the discussion given in the bases for Specification 3.1 is applicable here.

The low reactor water level instrumentation is set to trip when reactor water level is 127 inches above the top of the active fuel. This trip initi-ates closure of Group 2 and 3 primary containment isolation valves but does not trip the recirculation pumps, Ref. Section 7.3 and Figure 7.3-6 of the i I

UFSAR. For a trip setting of 127 inches above the top of the active fuel and a 60-second valve closure time, the valves will be closed before core uncovery occurs even for the maximum break in the line; and therefore, the setting is adequate.

1 The low low reactor water level instrumentation is set to trip when reactor water level is 79 inches above the top of the active fuel. This trip initiates closure of Groups 1 and 5 primary containment isolation valves, Ref.

Section 7.3 and Figure 7.3-6 of the UFSAR, activates the ECC subsystems, starts the emergency diesel generator and the gas turbine generator, and trips the recirculation pumps. This trip setting level was chosen to be high enough I to prevent spurious operation but low enough to initiate ECCS operation and primary system isolation so that post accident cooling can be effectively accomplished and the guideline values of 10 CFR 100 will not be violated.

For the complete circumferential break of a 28-inch recirculation line and with the trip setting given above, ECCS initiation and -

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Millstone Unit 1 B 3/4 2-1 Amendment No. 55 .

sons

U.S. Nuclsar Regulatory Commission B16312\ Attachment 4\Page 8 INSERTI (page B 3/4 2-1)

Entry into associated action statements may be delayed for up to two hours provided the associated actuation function maintains actuation capability. A two-hour allowance for testing is judged acceptable based upon:

a) Remaining capability to actuate. Testing of one sensor does not render the actuation system inoperable, but iather, simply increases the single failure vulnerability of one actuation function in one channel.

b) Low likelihood of an event requiring the actuation of a primary containment isolation or an Emergency Core Cooling System.

c) Reasonable test interval. The two-hour test duration provides a reasonable amount of time for testing without placing undo time constraints on personnel.

If it is discovered that an instrument channel cannot meet the surveillance requirement, the instrument channel shall be declared inoperable.

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3.2 PROTECTIVE INSTRLatDffATION nure i

Two air ejector off-gas monitnrs are provided and when their trip point is reached, cause an isolation of the air ejector eff-gas line. Isolation is i

initiated when both instruments reach their high trip point or one has an

ur. scale trip and the other a downscale trip. There is a 15-minute delay before the air ejector off-gas isolation valve is closed. This delay is accounted for by the 30-minute holdup time of the off-gas before it is i released to the stack.

t Both instruments are required for trip but the instruments are so

designed that any instrument failure gives a downscale trip. The trip

' settings of the instruments are set so that any instrument failure gives a downscale trip. The trip settings of the instruments are set so that the I

instantaneous stack release rate limit given in Specification 3.8 is not r 3 exceeded.

I Tmawd 4 Three sets of two radiation monitors provide signals to initiate IJ t isolation of the reactor building and steam tunnel ventilation and operation of the standby gas treatment system when these systems are aligned for automatic actuation. Additionally, these monitors provide indication of radiological conditions for the areas they monitor and alarm in the event of abnormal conditions. One set of monitors is located adjacent to the reactor building ventilation exhaust duct, one set is located in the vicinity of the fuel pool, and the other set is located adjacent to the steam tunnel ventila-tion exhaust duct. A high level trip on any one of the six monitors or two downscale trips on any one set of monitors will provide signals to the standby gas treatment system initiation and normal ventilation isolation logics. Trip settings of 100 ar/hr on the fuel pool monitor,11 ar/hr on the ventilation duct monitor, and 50 mr/hr on the steam tunnel ventilation monitor are based on initiating nonnal ventilation isolation and standby gas treatment system operation when a gross release of radioactive material exists.

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l MILLSTONE UNIT 1 8 3/4 2-5 o244 Amendment No. JJ 98

U.S. Nuc!sar Regulatory Commission B16312%ttachment 4\Page 9 INSERT J I

(page 3/4 2-5)

Entry into associated action statements may be delayed for up to two hours. A two-hour allowance for testing is judged acceptable based upon:

a) Low likelihood of an event requiring the isolation of the air ejector off-gas system.

b) Reasonable test interval. The two-hour test duration provides a reasonable amount of time for testing without placing undo time constraints on personnel, if it is discovered that an instrument channel cannot meet the surveillance requirement, the instrument channel shall be declared inoperable.

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3.7 CONTAIl0ENT 3YSTM5 l

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a radioactive asthyl iodide removal efficiency of at least 95 percent for expected accident conditions. If the efficiencies of the HEPA filters

' and charcoal adsorbers are as specified, the resulting doses will be less than the 10 CFR 100 guidelines for the acciden's analyzed. Operation of the fans signify different from the design flow will change the removal efficiency of the HEPA filters and charcoal adsorbers.

only one of the two standby gas treatment trains is needed to clean up the reactor building atmosphere upon containment isolation. If one train is found to be inoperable, there is no inesediate threat to the containment i system performance, and reactor operation or refueling operation may !

continue while repairs are being made. During RUN, STARTUP/ HOT STAND 8Y and HOT SHUTDOWN, OPERA 8ILITY of the standby gas treatment system is required.

Standby gas treatment system OPERABILITY is also required during COLD SHUTDOWN or REFUELING when situations exist where a significant release of fission products can be postulated, such as moving the fuel cask, irradiated l fuel or other loads in contairment; or when performing CORE ALTERATIONS or !

operations with a potential for draining the reactor vessel when the vessel contains irradiated fuel. .During a REFUELING OUTAGE, when reactor coolant temperature is less than or equal to 212" F and secondary containment <

integrity is required, two off-site power sources (345 kV or 23 kV) and one 1 emergency power source would provide an adequate and reli.ble source of l power and allow diesel or gas turbine preventative maintenance. Likewise, one source of offsite power (345.kV or 23 kV) and two emer sources provide an adequate and reliable source of power. gency power j

C. Secondary Containment The secondary containment is designed to minimize any ground level release of radioactive materials which might result from a serious accident. The reactor building provides secondary containment during reactor operation, when the drywell is sealed and in service; the reactor building provides primary containment when the reactor is shutdown and !

the drywell is open, as during refueling. Because the secondary containment is an integral part of the complete containment systes, secondary containment integrity is required at all times that primary containment is required. Secondary containment integrity is also required when activities having the potential of significant fission products release, such u movement of the fuel cask, irradiated fuel, or other loads

_~' in containment are performed. Administrative controls ensure that loads moved in containment, which may result in significant release of fission CM w products, are evaluated to determine if secondary containeert is required.

D. Primary Containment Isolation Valves Double isolation valves are provided on lines penetrating the primary containment. Closure of one of the valves in each line would >e 4, sufficient to maintain the integrity of the pressure suppression system.

Automatic initiation is required to minimize the potential leakage paths from the containment in the event of a loss of coolant accident.

MILLSTONE UNIT 1 o247 83/47-6 Amendment No. J7, 98

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U.S. Nucisar Regulatory Commission B16312\ Attachment 4\Page 10 INSERT K l

(page B 3/4 7-6) l If secondary containment is inoperable in RUN, STARTUP/ HOT STANDBY or HOT l SHUTDOWN, it must be restored to OPERABLE status within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . The 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months time provides a period of time to correct the problem that is commensurate with the )

1 importance of maintaining secondary containment integrity in RUN, STARTUP/ HOT STANDBY or HOT SHUTDOWN. This time period also ensures that the probability of an accident (requiring secondary containment OPERABILITY) occurring during periods where secondary containment is inoperable is minimal. If secondary containment cannot be restored to OPERABLE status within the required time, the plant must be brought to a condition in which the LCO does not apply. An additional 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months are allowed to achieve this condition. The allowed times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.

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NOV0.1Tjjf j a 4.7 CONTAINMENT SYSTEMS BASES B. Standby Gas Treatment System and C. Secondary Containment . l Pressure drop across the combined HEPA filters and charcoal adsorbers of l less than 7 inches of water, at the system design flow rate, will !

indicate that the filters and adsorbers are not clogged by excessive '

amounts of foreign matter. Heater capability and pressure drop should be determined at least once per operating cycle to show system performance .

capability.

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Millstone Unit 1 B 3/4 7-9a Amendment No. p ,.67 9103

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U.S. Nuclear Regulatory Commission B16312\ Attachment 4\Page 11 INSERT L (page B 3/4 7-9a)

Verifying that secondary containment access doors are closed ensures that the infiltration of outside air of such a magnitude as to prevent maintaining the desired negative pressure does not occur. Maintaining secondary containment OPERABILITY, in accordance with the definition for SECONDARY CONTAINMENT INTEGRITY, requires verifying at least one door in each access opening is closed. The access openings covered by Surveillance Requirement 4.7.C.1.b are the normal and

. emergency double-door accesses on Reactor Building elevation 14' 6" and the railroad track bay access doors. The monthly frequency for the surveillance requirement is considered adequate in view of the other indications of door status that are available.

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Docket No. 50-245

B16312 J

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l Attachment 4 i Millstone Nuclear Power Station, Unit No.1 Proposed Technical Specification Revision l ~ Allowable Outage Times

! Retyped Technical Specifications and Bases i

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March 1997 i

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TABLE 3.1.1 (Centinued) .

REACTOR PROTECTION SYSTEM (SCRAM) INSTRUMENTATION REQUIREMENTS 5

9:

3 Minimum Number 8 of Operable Modes in which Function

Inst. Channels Trip Function Trip Level Setting Must Be Operable Action

F per Trip (1) REFUEL / STARTUP/ HOT

System SHUTDOWN (8,11) STAND 8Y RUN I

2 Turbine Condenser Low 1 23 in. Hg. Vacuum X (3) X (3) X A or C Vacuum 4 (6) Main Steamline Isolation s 10% Valve Closure X (3) X (3) X A or C Valve Closure 2 Turbine Control Valve See Section 2.1.2 F X (4) X (4) X (4) A or C

$ Fast Closure

7 2 Turbine Stop Valve s 10% Valve Closure X (4) X (4) X (4) A or C a Notes: 1. A channel may be placed in an inoperable status for up to two hours g during periods of required surveillance without placing the Trip System

= in the tripped condition provided the associated Trip Function maintains z trip capability. Otherwise, there shall be two operable or tripped trip

? systems for each function.

w 2. Permissible to bypass, with control rod block, for reactor protection P system reset in REFUEL and SHUTDOWN positions of the reactor mode switch.

w 3. Bypassed when reactor pressure is < 600 psig.

P 4. Bypassed when first stage turbine pressure is less than that which w corresponds to 50% rated reactor thermal power.

?

M.

TABLE 3.2.1 .

INSTRUMENTATION THAT INITIATES PRIMARY CONTAINMENT ISOLATION FUNCTIONS E Minimum Number of l Operable Instrument Channels Per Trip

! System (1) Instruments Trio Level Settina Action (3) e g 2 Reactor Low Water 2 127 inches above top of active fuel A 2 Reactor Low Low Water 79 (+4-0) inches above top of active fuel A 2 (4) High Drywell Pressure 1 2 psig A 2 (2) (5) High Flow Main Steamline s 120% of rated steam flow B 2 of 4 in each of High Temperature Main 2 subchannels Steamline Tunnel 5 200*F 8 2 Low Pressure Main 1 825 psig B Steamlines 2 High Flow Isolation 164 inches 1 trip setting (water differential C Condenser Line on steam line) 2 150 inches.

44 inches 2 trip setting (water differential

, on water side) 1 35 inches.

s

(1) A channel may be placed in an inoperable status for up to two hours during periods of required

" surveillance without placing the Trip System in the tripped condition provided the associated

" function maintains trip capability. Otherwise, whenever primary containment integrity is required, there shall be two operable or tripped trip systems for each function, except for low pressure main steamline which only need be available in the RUN position.

(2) Per each steamline. .

(3) Action: If the first column cannot be met for one of the trip systems, that trip system shall be tripped. '

g If the first column cannot be met for both trip systems, the appropriate actions listed below shall be taken:

l- A. Initiate an orderly shutdown and have reactor in cold shutdown condition in 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

g B. Initiate an orderly load reduction and have reactor in HOT STANOBY within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

C. Close isolation valves in isolation condenser system. '

(4) May be bypassed when necessary by closing the manual instrument isolation valve for PS-1621, A through y D, during purging for containment inerting or deinerting.

(5) Minimum number of operable instrument channels per trip system requirement does not have to be met for a i g steamline if both containment isolation valves in the line are closed.

O.

.. . . _ . . _ . _ .. ___ ._. . _ . . .. _ _._ _ _ __ _ __ _ _ . . . - _ . ..__ _ _ _ _ . ~ .

yif TABLE 3.2.2 (Continued)

% INSTRUNENTATION THAT INITIATES Af5 CONTROLS THE ENUtGENCY CORE C0OLING SYSTEMS 8 i F

3 NOTE:

1) A channel may be placed in an inoperable status for up to two hourc during periods of required surveillance without placing the Trip System in the tripped cordition provided the associated Trip Function maintains trip capability. Otherwise, if the first column cannot be met for one of the trip systems, that system shall be tripped. If the first column cannot be met for both trip systems, immediately initiate an orderly shutdown to cold conditions.

M.

= i f

a 5

a

.if l

~

@E TABLE 3.2.3 (Continued)

< INSTRUMENTATION THAT INITIATES R00 BLOCK E

E

=

& Notes:

N i (1) A channel may be placed in an inoperable status for up to two hours during periods of required surveillance without placing the Trip System in the tripped condition provided the associated function maintains trip capability. Otherwise, for the STARTUP/ HOT STAN08Y and RUN positions of the

Reactor Mode Selector Switch, there shall be two operable or tripped trip systems for each function except the scram discharge volume - water level high and the SRM rod blocks; IRM downscale are not .

operable in the RUN position and APRM downscale need not be operable in the STARTUP/ HOT STAND 6Y mode.

If the first column cannot be met for one of the two trip systems, this condition may exist for up to i

seven days provided thsi. during that time the operable system is functionally tested immediately and daily thereafter; if this condition lasts longer than seven days, the system shall be tripped. If the first column cannot be met for both trip systems, the systems shall be tripped. ,

(2) W is the recirculation flow required to achieve rated core flow expressed in percent.

w

) (3) IRM downscale may be bypassed when it is on its lowest range.

[ (4) This function may be bypassed when the count rate is 2100 cps or when all IRM range switches are above Position 2.

t (5) One of these trips may be bypassed. The SRM function may be bypassed, in the higher IRM ranges, when the IRM upscale rod block is operable. t (6) The trip may be bypassed when the reactor power is $,307,of rated. A RBM channel will be considered inoperable if there are less than half the total number of normal inputs from any LPRM level. [

i (7) There must be a total of at least four (4) operable or operating APRM channels.

(8) For the STARTUP/ HOT STANDBY and RUN positions of the Reactor Mode Selector Switch, there shall be one (1) !

g scram discharge volume - water level high instrument per instrument volume tank required to be operable. If !

g either of the instruments become inoperable, a rod block shall be initiated within one hour. i

, n.

E a l E

1 1

[

_ . . _ . _ _ _ . . _ _ . _ _ . _ . ~ _ _ _ . _ _ _ . _ _ _ . _ _ _

i l 1.IMITING COWITION FOR OPERATION i

i

3.2 PROTECTIVE INSTRUMENTATION C.2. The minimum number of operable instrument channels specified in i Table 3.2.3 for the Rod Block Monitor may be reduced by one for j maintenance and/or testing for periods not in excess of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months in any 30-day period.

i

D. Air Eiector Off-Gas System i

1. Except as specified in 3.2.D.2 below, both air ejector off-gas

! system radiation monitors shall be operable during reactor power

operation. The trip settings for the monitors shall be set at a i value not to exceed the equivalent of the instantaneous stack release limit specified in Specification 3.8. The time delay j 4 l setting for closure of the steam jet-air ejector off-gas isolation !

valve shall not exceed 15 minutes.

i ,

2. One air ejector off-gas system radiation monitor may be placed in an l l inoperable status for up to two hours during periods of required l j surveillance without placing the Trip System in the tripped condition. !

i Otherwise, from and after the date that one of the two air ejector i off-gas system radiation monitors is made or found to be inoperable, l j' reactor power operation is permissible only during the succeeding 24 i hours, provided the inoperable monitor is tripped, unless such system

! is sooner made operable.

1 E. Reactor Buildina Ventilation Isolation. Steam Tunnel Ventilation Isolation and Standby Gas Treatment System Initiation i

! 1. Except as specified in 3.2.E.2 below, two reactor building ventilation i duct radiation monitors, two refueling floor radiation monitors and two steam tunnel ventilation radiation monitors shall be operable j whenever secondary containment integrity is required.

! 2. One of the two reactor building ventilation duct radiation monitors, i one of the two refueling floor radiation monitors, and one of the two i

steam tunnel ventilation radiation monitors may be inoperable for 24 hrs. If it is not restored to service in this time, the reactor

building ventilation system and steam tunnel ventilation system shall

{ be isolated and the standby gas treatment operated until repairs are

complete or until secondary containment integrity is not required.

j 3. The radiation monitors shall be set to trip as follows:

j a. Ventilation duct - 11 mr/hr.

b. Refueling floor - 100 mr/hr.

c. Steam tunnel ventilation - 50 mr/hr.

Millstone Unit 1 3/4 2-12 Amendment No. J, J,2, JJ, pp, 0288

LINITING ColWITION FOR OPERATION 3.7 CONTAINMENT SYSTEMS C. Secondary Containment

1. Secondary containment integrity, as defined in Section 1, shall be OPERABLE:

, a. When moving the fuel cask, irradiated fuel or other loads in containment which have the potential for causing a i significant release of fission products. {

b. When performing CORE ALTERATIONS or operations with a potential for draining the reactor vessel when the vessel contains irradiated fuel. l

c. When in RUN, STARTUP/ HOT STANDBY or HOT SHUTDOWN.

2. If the above cannot be met:

2

a. immediately suspend the activities listed in 3.7.C.I.a and 3.7.C.1.b; and

b. when in RUN, STARTUP/ HOT STANDBY, or HOT SHUTDOWN, restore secondary containment to OPERABLE status within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months or establish, within the succeeding 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , conditions where

secondary containment integrity is not required. '

i

SURVEILLANCE REQUIREMENTS 4.7 CONTAINMENT SYSTEMS C. Secondary Containment

1. Secondary containment surveillance shall be performed as indicated below:

a. A secondary containment capability test shall be conducted after isolating the reactor building and placing either standby gas treatment system filter train in operation. Such tests shall demonstrate the capability of the secondary containment to maintain a 1/4 inch of water vacuum with a filter train flow rate of not more than 1100 scfm. Secondary containment capability shall be demonstrated at three or more points within the containment prior to fuel movement and may be demonstrated up to 10 days prior to fuel movement. Secondary containment capability need not be demonstrated more than once per operat- -

ing cycle unless damage or modifications to the secondary containment have violated the integrity of the pressure retaining boundary of that structure.

b. At least once a month, verify at least one door in each secondary containment access opening is closed.

Millstone Unit 1 3/4 7-13 Amendment No. J 77, 77, 0289

3.1 REACTOR PROTECTION SYSTEN l

BASES l

The reactor protection system automatically initiates a reactor scram to:

1. preserve the integrity of the fuel cladding;

2. preserve the integrity of the primary system barrier; and

3. minimize the energy which must be absorbed, and prevent criticality following a loss of coolant accident.

These specifications provide the limiting conditions for operation necessary to preserve the ability of the system to tolerate single failures and still perform its intended function even during periods when instrument 1 channels may be out of service because of maintenance. When necessary, one I channel may be made inoperable for brief intervals to conduct required ;

functional tests and calibrations. Entry into associated action statements may be delayed for up to two hours provided the associated trip function maintains trip capability. A two-hour allowance for testing is judged acceptable based upon:

a. Remaining capability to trip. Testing of one sensor does not render the trip system inoperable, but rather, simply increases the single ;

failure vulnerability of one trip function in one channel. 1 Inoperabilities affecting diverse trip functions would require multiple failures.

b. Diversity of sensors available to provide the trip signals.

Surveillance testing is not performed on multiple variables' sensors simultaneously; so other trip functions either remain operable or were previously declared inoperable and placed on a tripped condition.

c. Low likelihood of an event requiring the initiation of a scram during this time frame.

d. Reasonable test interval. The two-hour test duration provides a reasonable amount of time for testing without placing undo time constraints on personnel.

e. Two-hour time interval is consistent with GE BWR Technical Specification (NUREG-0123).

f. Two hours represents one-half of the required action completion time (four hours) associated with an inoperable RPS trip function. ;

If it is discovered that an instrument channel cannot meet the surveillance requirement, the instrument channel shall be declared inoperable.

The reactor protection system is of the dual channel type. Ref.

Section 7.2 of the UFSAR. The system is made up of two independent logic channels, each having two subchannels of tripping devices. Each subchannel has an input from at least one independent sensor monitoring each of the critical parameters.

MILLSTONE UNIT 1 5 3/4 1-2 Amendment No, )),

0290

3.1 REACTOR PROTECTION SYSTEM BA$li The outputs of the subchannels are combined in a 1 out of 2 logic; i.e.,

an input signal on either one or both of the subchannels will cause a trip system trip. The outputs of the trip systems are arranged so that a trip on both channels is required to produce a reactor scram.

This system meets the requirements of the proposed IEEE Standard for Nuclear Power Plant Protection Systems issued September 13, 1966. The system has a reliability greater than that of a 2 out of 3 system and somewhat less than that of a 1 out of 2 system.

With the exception of the Average Power Range Monitor (APRM), Intermediate Range Monitor (IRM) channels, Main Steam Isolation Valve Closure, and Turbine Stop Valve Closure, each subchannel has one iastrument channel. When the rinimum condition for cperation on the number of operable instrument channels pu untripped protection logic channel is met or if it cannot be met and the affected protectioa trip system is placed in a tripped condition, the effectiveness of the protection system is preserved; i.e., the system c:.a tolerate a single failure and still perform its intended function or scramming the reactor. Three APRM instrument channels are provided for each protection trip system.

APRMs #1 and #3 operate contacts in a logic subchannel and APRMs #2 and

3 operate contacts in the other logic subchannel.

APRMs #4, #5 and #6 are arranged similarly in the other protection trip system. Each protection trip system has one more APRM than is necessary to meet the minimum number requ: red per channel, This allows the bypassing of 4

one APRM per protection trip system for maintenance, testing or calibration.

]

l MILLSTONE UNIT 1 8 3/4 b2a Amendment No. JJ, 0290

_ _ _ _ _ . _ _ . _ _ _ _ _ _ _ . ~ _ . - - - - .

3.2 PROTECTIVE INSTRUNENTATION i BASES f

! In addition to reactor protection instrumentation which initiaties a ,

reactor scram, protective instrumentation has been provided which initiates l

action to mitigate the consequences of accidents which are beyond the

operator's ability to control or terminates operator errors before they result

in serious consequences. This set of specifications provides the limiting i conditions of operation for the primary system isolation function, initiation

of the emergency core cooling system, control rod block, and standby gas treatment systems. The objectives of the specifications are to assure the i

effsetiveness of the protective instrumentation, when required, by preserving

! its capability to tolerate a signal failure of any component of such systems even during periods when portions of such systems are out of service for j maintenance. When necessary, one channel may be made incpa able for brief

intervals to conduct required functional tests and calibrations and to

{ prescribe the trip settings required to assure adequate performance. Entry )

! into associated action statencnts may be delayed for up to two hours provided i

the associated actuation function maintains actuation cap bility. A two-hour

, allowance for testing is judged acceptable based upon:

{ a. Remaining capability to actuate. Testing of one sensor does not i render the actuation system inoperable, but rather, simply increases i j the single failure vulnerability of one actuation function in one !

channel.

b. Low likelihood of an event requiring the actuation of a primary l containment isolation or an Emergency Core Cooling System.

j c. Reasonable test interv91. The two-hour test duration provides a

{ reasonable amount of time for testing without placing undo time

constraints on personnel.

i i

If it is discovered that an instrument channel cannot meet the surveillance requirement, the instrument channel shall be declared inoperable.

Isolation valves are installed in those lines that penetrate the primary containment and must be isolated during a loss of coolant accident so that the radiation dose limits are not exceeded during an accident condition. Actua-tion of these valves is initiated by protective instrumentation'shown in Table 3.2.1 which senses the conditions for which isolation is required. Such instrumentation must be available whenever primary containment integrity is required. The objective is to isolate the primary containment so that the guideline values of 10 CFR 100 are not exceeded during an accident.

The instrumentation which initStes primary system isolation is connected in a dual bus arrangement. Thus, the discussion given in the bases for Specification 3.1 is applicable here.

NILLSTONE UNIT 1 B 3/4 2-1 Amendment No. JJ, 0291 i ._ _ _ _ _-

3.2 PROTECTIVE INSTRUAENTATION BASES

=

The low reactor water level in::trumentation is set to trip when reactor water level is 127 inches above the top of the active fuel. This trip initi-ates closure of Group 2 and 3 primary containment isolation valves but does not trip the recirculation pumps. Ref. Section 7.3 and Figure 7.3-6 of the UFSAR. For a trip setting of 127 inches above the top of the active fuel and 4

a 60-second valve closure time, the valves will be closed before core uncovery 1 occurs even for the maximum break in the line; and therefore, the setting is

adequate.

The low low reactor water level instrumentation is set to trip when reactor water level is 79 inches above the top of the active fuel. This trip initiates closure of Groups 1 and 5 primary containment isolation valves, Ref.

Section 7.3 and Figure 7.3-6 of the UFSAR, activates the ECC subsystems, ;

starts the emergency diesel generator and the gas turbine generator, and trips '

the recirculation pumps. This trip setting level was chosen to be high enough to prevent spurious operation but low enough to initiate ECCS operation and primary system isolation so that post accident cooling can be effectively i accomplished and the guideline values of 10 CFR 100 will not be violated. l For the complete circumferential break of a 28-inch recirculation line '

and with the trip setting given above, ECCS initiation and ,

l 1

I i

! NILLSTONE UNIT 1 B 3/4 2-la Amendment No. )),

0291

4

)

3.2 PROTECTIVE INSTRUNENTATION BASES i

i Two air ejector off-gas monitors are provided and when their trip point 1

}

is reached, cause an isolation of the air ejector off-gas line. Isolation is I

initiated when both instruments reach their high trip point or one has an upscale trip and the other a downscale trip. There is a 15-minute delay

before the air ejector off-gas isolation valve is closed. This delay is accounted for by the 30-minute holdup time of the off-gas before it is released to the stack.

e 3 Both instruments are required for trip but the instruments are so designed that any instrument failure gives a downscale trip. The trip

' settings of the instruments are set so that any instrument failure gives a downscale trip. The trip settings of the instruments are set so that the

instantaneous stack release rate limit given in Specification 3.8 is not i exceeded.

l

! Entry into associated action statements may be delayed for up to two '

i hours. A two-hour allowance for testing is judged acceptable based upon:

i

{ a. Low likelihood of an event requiring the isolation of the air ejector off-gas system.

j b. Reasonable test interval. The two-hour test duration provides a j reasonable amount of time for testing without placing undo time

constraints on personnel.

i i

If it is discovered that an instrument channel cannot meet the j

surveillance requirement, the instrument channel shall be declared inoperable.

i Three sets of two radiation monitors provide signals to initiate j isolation of the reactor building and steam tunnel ventilation and operation

of the standby gas treatment system when these systems are aligned for automatic actuation. Additionally, these monitors provide indication of radiological conditions for the areas they monitor and alarm in the event of abnormal conditions. One set of monitors is located adjacent to the reactor building ventilation exhaust duct, one set is located in the vicinity of the fuel pool, and the other set is located adjacent to the steam tunnel ventila-tion exhaust duct. A high level trip on any one of the six monitors or two downscale trips on any one set of monitors will provide signals to the standby gas treatment system initiation and normal ventilation isolation logics. Trip settings of 100 mr/hr on the fuel pool monitor,11 mr/hr on the ventilation duct monitor, and 50 mr/hr on the steam tunnel ventilation monitor are based on initiating normal ventilation isolation and standby gas treatinent system operation when a gross release of radioactive material exists.

MILLSTONE UNIT 1 B 3/4 2-5 Amendment No. # , pp, 0292

!. - i j

j 3.7 CONTAllglENT SYSTEMS

! ma m

! I

a radioactive methyl iodide removal efficiency of at least 95 percent for l i expected accident conditions. If the efficiencies of the HEPA filters 1 4

and charcoal adsorbers are as specified, the resulting doses will be less i

{ than the 10 CFR 100 guidelines for the accidents analyzed. Oparation of '

i the fans signify different from the design flow will change the removal !

! efficiency of the HEPA filters and charcoal adsorbers. !

Only one of the two standby gas treatment trains is needed to clean up

! the reactor building atmosphere upon containment isolation. If one train is

! found to be inoperable, there is no immediate threat to the containment j system performance, and reactor operation or refueling operation may

continue while repairs are being made. During RUN, STARTUP/ HOT STANDBY and l HOT SHUTDOWN, OPERABILITY of the standby gas treatment system is required.

Standby gas treatment system OPERABILITY is also required during COLD .

SHUTDOWN or REFUELING when situations exist where a significant release of fission products can be postulated, such as moving the fuel cask, irradiated i

' fuel or other loads in containment; or when performing CORE ALTERATIONS or operations with a potential for draining the reactor vessel when the vessel contains irradiated fuel. During a REFUELING OUTAGE, when reactor coolant temperature is less than or equal to 212' F and secondary containment l integrity is required, two off-site power sources (345 kV or 23 kV) and one

emergency power source would provide an adequate and reliable source of j power and allow diesel or gas turbine preventative maintenance. Likewise,

one source of offsite power (345 kV or 23 kV) and two emergency power

! sources provide an adequate and reliable source of power.

s i C. Secondary Containment i

! The secondary containment is designed to minimize any ground level release of radioactive materials which might result from a serious !

accident. The reactor building provides secondary containment during

reactor operation, when the drywell is sealed and in service; the reactor l

building provides primary containment when the reactor is shutdown and l l the drywell is open, as during refueling. Because the secondary '

containment is an integral part of the complete containment system, i

secondary containment integrity is required at all times that primary containment is required. Secondary containment integrity is also required when activities having the potential of significant fission products f releare, such as movement of the fuel cask, irradiated fuel, or other loads in containment are performed. Administrative controls ensure that loads moved in containment, which may result in significant release of fission products, are evaluated to determine if secondary containment is required.

If secondary containment is inoperable in RUN, STARTUP/ HOT STANDBY or HOT SHUTDOWN, it must be restored to OPERABLE status within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . The 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months time provides a period of time to correct the problem that is commensurate with the importance of maintaining secondary contair, ment integrity in RUN, STARTUP/ HOT STANDBY or HOT SHUTDOWN. This time period also ensures that the probability of an accident (requiring secondary containment OPERABILITY) occurring during periods where secondary containment is inoperable is minimal . If secondary containment cannot be restored to OPERABLE status NILLSTONE UNIT 1 B 3/4 7-6 Amendment No. pf, pp, !

0277

]

_. _ _ _ - . _ _ _ . . _ _ .. . .. - .. - _ - - - - - - = . -- __ -

3.7 CONTAINNENT SYSTEMS j matra i l 1

l

! within the required time, the plant must be brought to a condition in which j the LCO does not apply. An additional 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months are allowed to achieve this I

condition. The allowed times are reasonable, based on operating experience, j

to reach the required plant conditions from full power conditions in an '

orderly manner and without challenging plant systems, t

D. Primary Containment Isolation Valves

)

Double isolation valves are provided on lines ponetrating the primary '

containment. Closure of one of the valves in each line would be i j sufficient to maintain the integrity of the pressure suppression system. l l Automatic initiation is required to minimirr. the potential leakage paths !

! from the containment in the event of a lo".s of coolant accident. ;

I l j

b i i i l l

1 I

l

1 i

i I

l i

i 1

- 1 i

l I

4 i I

$ i I

NILLSTONE UNIT 1 B 3/4 7-6a Amendment No. J7, 0277

o ,

4.7 CONTAllWENT SYSTEMS BASES B. Standby Gas Treatment System and C. Secondary Containment Pressure drop across the combined HEPA filters and charcoal adsorbers of less than 7 inches of water, at the system design flow rate, will indicate that the filters and adsorbers are not clogged by excessive amounts of foreign matter. Heater capability, pressure drop should be determined at least once per operating cycle to show system ~ performance capability.

Verifying that secondary containment ' access doors are closed ensures that the infiltration of outside air of such a magnitude as to prevent maintaining the desired negative pressure does not occur. Maintaining secondary containment OPERABILITY, in accordance with the definition for SECONDARY CONTAINMENT INTEGRITY, requires verifying at least one door in each access opening is closed. The access openings covered by Surveillance Reauirement 4.7.C.I.b are the normal and emergency double-door accesses on' Reactor Building elevation 14' 6" and the railroad track bay access doors. The monthly frequency for the surveillance requirement is considered adequate in view of the other indications of door status that are available.

I i

MILLSTONE UNIT 1 B 3/4 7-9s Amendment No. 77, 77.

0294

-

ML20136B343

Text

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