ML20086A645

Proposed Tech Specs Re Leakage Criteria for Coolant Pressure Boundary Piping

ML20086A645
Person / Time
Site:	Peach Bottom
Issue date:	11/10/1983
From:	PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:
Shared Package
ML20086A614	List: ML20086A610 ML20086A634 ML20086A645
References
NUDOCS 8311160056
Download: ML20086A645 (7)

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TABLE 3.2.E INSTRUMENTATION THAT MONITORS DRYWELL LEAK DETECTION i i

Minimum No.

of Operable Instrument Channels Instrument (1) Action (2) 1 Equipment Drain Sump Flow Integrator A i or Floor Drain Sump Flow Integrator h NOTES FOR TABLE 3.2.E

1. The two (2) flow integrators, one for the equipment drain sump and the other for the floor drain sump, are redundant ~

instrument. systems. l

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eO gg 2. . Action ,

LeC Q A. Whenevery both of these systems are made or found to be inoperable,

-g reactor nower operation is permissible only during the succeeding 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, t oo or the reactor shall be in at least hot shutdown within the next 12 d@ hours and . in cold shutdown condition within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

dce g . Refer to Specification 3.6.C L _

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TABLE 4.2.E MINIMUM TEST AND CALIBRATION FREQUENCY FOR DRYhTLL LEAK DETECTION Instrument Channel Instrument Functional Calibration Instrument Test Frecuency Check

1) Equipment Drain Sump Flow Integrator (1) Once/3 months once/ day

2) Floor Drain Sump Flow Integrator (1) Once/3 months once/ day 1

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PBAPS 3.2 BASES (Cont'd) trip and the other a downscale trip. There is a fifteen 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 i stack during reactor power operation when the recombiner system is not operating.

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 the instantaneous stack release rate limit given in Sepcification 3.8 is not exceeded.

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Four sets of two radiation monitors are provided which initiate the Reactor Building Isolation function and operation of the standby gas treatment system. Four instrument channels monitor the radiation from the refueling area ventilation exhaust ducts and four instrument channels monitor the building ventilation below the refueling floor.

Each set of instrument channels is arranged in a 1 out of 2 twice trip logic.

Trio settings of less than 16 mr/hr for the monitors in the l

refueling area ventilation exhaust ducts are based upon initiating normal ventilation isolation and standby gas treatment system operation so that none of the activity released during the refueling accident leaves the Reactor Building via the normal ventilation path but rather all the j

activity is processed by the standby gas treatment system.

Flow integrators are used to record the integrated flow of liquid from the drywell sumps. The integrated flow is indicative of primary coolant leakage.

For each parameter monitored, as listed in Table 3.2.F, there are at least two (2) channels of instrumentation. By comparing readings between the channels, a near continuous surveillance of instrument performance is available. Any deviation in readings will initiate an early recalibration, thereby maintaining the quality of the instrument readings..

The recirculation pump trip has been added at the suggestion of ACRS as a means of limiting the consequences of the unlikely occurrence of a failure to scram during an anticipated transient.. The response of the plant to this costulated event fall within the envelope of study events given in General Electric Company Topical Report, NEDO-10349, dated March, 1971.

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7 PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.6.B Coolant Chemistry (Cont'd) 4.6.B Coolant Chemistry (Cont'd) b) Chloride Concentration Time above 2 weeks /vear 0.2 opa '

Maximum limit 1.0 ppm c) pH During overations, if the conductivity exceeds 1.0 umho/cm, pH shall be measured and .

brought within the 5.6 to 8.6 range within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. If the pM cannot be corrected, or if the .

pH is outside a range of 4 to 10, the unit shall be placed in Hot Shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in Cold Shutdown with 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

C. Coolant Leakage C. Coolant Leakage

1. Any time irradiated fuel is 1. Reactor coolant system leakage in the reactor vessel and reactor shall be determined by the coolant temperature is above primary containment (Drywell) 712 degrees F, the rate of sump collection and flow reactor coolant leakage to-the monitoring system and recorded primary containment from unidenti- every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or.less, fled sources shall not exceed 5 gallons per minute. The rate of change of unidentified leakage shall not exceed 2 gallons per minute per 74 hour8.564815e-4 days <br />0.0206 hours <br />1.223545e-4 weeks <br />2.8157e-5 months <br /> surveillance period when the reactor is operated in the "Run" mode. In addition, the total reactor coolant system leakage into the primary contain-ment shall not exceed 25 gpm averaged over any 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> ,

surveillance period.

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PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.6.C. Coolant Leakage

2. The primary containment (Drywell) ,

sump collection and flow monitoring system shall be operable during reactor power operation. From and after the time that this system is made or found to be inoperable for any reason,' reactor power operation is permissible only during the succeeding 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> unless the system -

is made operable sooner. For purposes of this paragraph, the

• primary containment (Drywell) sump collection and flow monitoring system operability is defined as the ability to measure reactor. coolant leakage.

3. If the conditions in 1 or 2 cannot be met, an orderly shutdo' a shall be initiated and the reactor shall be in at least Hot Shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in Cold Shutdown Condition within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

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PBAPS 3.6.C & 4.6.C BASES Coolant Leakage Allowable leakage rates of coolant from the reactor coolant system have been based on the predicted and experimentally observed behavior of cracks in pines and on the ability to makeup coolant system leakage in the event of loss of offsite ac power. The normally expected background leakage due to equinment design and the detection capability for determining coolant system leakage were also considered in establishing the limits. The behavior of cracks in piping systems has been experimentally and analytically investigated as part of the USAEC sponsored Reactor Primary Coolant System Rupture Study (the Pipe Runture Study). Work utilizing the data obtained in this study indicates that leakage from a crack can be detected before the crack grows to a dangerous or critical size by mechanically or thermally induced cyclic loading, or stress corrosion cracking or some other mechanism characterized by gradual crack growth. This evidence suggests that for leakage somewhat greater than the limit specified for unidentified leakage, the probability is small that imperfections or cracks associated with such leakage would grow rapidly.

However, the estab31shment of allowable unidentified leakage j greater than that given in 3.6.C on the basis of the data presently available would be premature because of uncertainties associated with the data. For leakage of the order of 5 gpm, as specified in 3.6.C, the experimental and analytical data suqqest a reasonable margin of safety that such leakage maanitude would not result from a crack approaching the critical size for ranid propagation. Leakage less than the magnitude specified can be detected reasonably in a matter of a few hours utilizing the available leakage detection schemes, and if the origin cannot be determined in a reasonably short time, the olant should be shutdown to allow further investigation and corrective actic:..

A rate of change limit of ? gpm per 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> surveillance period is snecified to provide additional conservatism. This limit is applicable to reactor onerations in the "Run" mode, during which time there is little variation in primary coolant system pressure.

The limit does not apply to the "Startup" mode since this period is characterized hv large variations in system pressure and consequently, changes in measured leakage wouli not be indicative of system degradation. During the limited duration of the startup phase, the 5 gom limit will ensure the integrity of the primary coolant system.

The total leakage rate consists of all leakage, identified and unidentified, which flows to the drywell floor drain and equipment drain sumps. Both the Drywell floor drain and the equipment drain sumps have pump-out capacitites of 50 gpm per pump. Any one pump can therefore handle in excess of the maximum allowable total leakage of 25 gnm. If the ability to measure pump-out flow from either of these sumps is lost, the inoperable sur.p will overflow

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f into the remaining operable sumo. The remaining operable sump pump-out flow will then represent the total leakage rate. During the time when one sump is overflowing, any increase in total flow will be assumed to be from an unidentified source. This primary containment (Drywell) sump collection and flow monitoring system can provide viable measurement of reactor coolant system leakage so long as one pump and its associated flow meter are operable.

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