ML17208A480

Proposed Tech Spec Changes,Increasing Combined Secondary Containment Bypass Leakage Rates & Intake of Outside Air Into Control Room

ML17208A480
Person / Time
Site:	Saint Lucie
Issue date:	04/18/1980
From:	FLORIDA POWER & LIGHT CO.
To:
Shared Package
ML17208A479	List: ML17208A478 ML17208A480
References
NUDOCS 8004230464
Download: ML17208A480 (10)

Text

CONTAINMENT SYSTEHS CONTAINMENT LEAKAGE LIMITING CONDITION FOR OPERATION 3.6.1.2 Containment leakage rates shall be limited to:

a. An overall integrated leakage rate of:=

l. < La, 0.50 percent by weight of the containment air per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at P, (39.6 psig), or

2. < Lt, 0.32 percent by weight of the containment air per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at a reduced pressure of Pt, (19.8 psig).

b. A combined leakage rate of < 0.60 La for all penetrations and valves subject to Type B and C tests as identified in Table 3.6-1 when pressurized to Pa.

c. A combined leakage rate of < 0. 27 La for all penetrations identified in Table 3.6-1 as secondary containment bypass leakage paths when pressurized to Pa.

APPLICABILITY: NODES 1, 2, 3 and 4.

ACTION:

With either (a) the measured overall integrated containment leakage rate exceeding 0.75 La or 0.75 Lt, as applicable, or (b) with the measured combined leakage rate for aTl penetrations and valves subject to Types B and C tests exceeding 0.60 La or (c) with the combined bypass leakage rate

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exceeding 0. 27 La, restore the leakage rate(s) to within the limit(s) prior to increasi ng the Reactor Coolant System temperature above 200'F.

SURVEILLANCE RE UIREMENTS 4.6.1.2 The containment leakage rates shall be demonstrated at the following test schedule and shall be determined in conformance with the criteria specified in Appendix J of 10 CFR 50 using the methods and provisions of ANSI N45.4-1972:

a. Three Type A tests (Overall integrated Containment Leakage Rate) shall be conducted at 40 + 10 month intervals during shutdown at either Pa ( 39.6 psig) or at Pt ( 19.8 psig) during each 10-year ST. LUCIE - UNIT 1 3/4 6-2 4/18/80

CONTAINMENT SYSTBiS SUR'lEILLANCE REQU IRB1ENTS Continued) service period. The third test of each set shall be conducted during the shutdown for the 10-year plant.inservice inspection..

b. If any periodic Type A test fails to meet either .75 L or .75 L, the test schedule for subsequent Type A tests shall b reviewed and approved by the Commission. If two consecutive Type A tests fail to meet either .75 L or .75 L , a=-Type A test shall be perform d at least every 18 mont~is until two con-secutive Type A tests me t either .75 L or .75 L at which time the above test schedule may be resumed.

c. The accuracy of each Type A test shall be verified by a supplemental test which:

l. Confirms the accuracy of the Type A test by verifying that the difference between supplemental and Type A test data is within 0.25 L or 0.25 Lt, a

2.. Has a duration sufficient to establish accurately the change in leakage between the Type A test and the supplemental test

3. Requires the quantity of gas injected into th containment or bled from the containment during the supplementa'1 test to be equivalent to at least 25 percent, of the total measured leakage rate at P- (39.6 psig) or Pt (19.8 psig).

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d. Type B and 'C tests shall be conducted with gas at P '39;6 psig) at intervals no greater than 24 months except for tests in-volving air locks..

e. The combined bypass leakage rate shall be determined to be

< 0.27 L by applicable Type B and C tests at least once per 24 months except for penetrations which are .not individually testable; penetrations not individually testable shall be determined to have no detectable leakage when tested with soap bubbles while the containment is pressurized to P (39.6 psig) during each Type A test.

Air locks shall be tested and demonstrated OPERABLE per Surveillance Requirement 4.6.1.3.

ST. LUCIE - UNIT 1 3/46-3 4/18/80

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PLANT SYSTEHS SURVEILLANCE RE UIREHENTS Continued)

e. At. least once per 18 months by:

l.'erifying that the pressure drop across the combined HEPA filters and charcoal adsorber banks is < 4.15 inches Hater Gauge while operating the ventilation system a.t a flow rate. of 2000 cfm + 10/..

2.'erifying A

that on a containment i'solation signal or chlorine accident detection signal, the system automatically isolates the control room within 35 seconds and swi"tches into a recirculation mode. of operation with flow through the HEPA filters and charcoal adsorber banks.

3. 'eri,ying that the system maintains the control room at a positive pressure of > 1/8 inch H.G. relative to the outside atmosphere during system operation with <450

'cfm outside air intake.

f."" After each complete or partial replacement of.a HEPA filter bank by verifying that the HEPA filter banks remove > 99il of the DQP when they are tested in-p'lace in accordance with ANSI

. N510-1975 rate of 2000 cfm + 10!.., A while operating the ventilation system at a flow f

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g. After each complete or partial replacement of a charcoa1 adsorber bank by verifying that th charcoal adsorbers remove

> 99; of a halogenated hydrocarbon refrig rant test gas when they are tested in-place in accordance with ANSI N510-1975 while operating the ventilation system at a flow rate of 2000

+ 10/. 'fm ST. LUCIE - UNIT 1 3/4 7-23 4/1 8/80

SAFETY EVALUATIOH 0

Re." St. Lucie Unit.l;,'ocket No 50-335 Proposed Amendment Containment & Control Room Leakage I. Introduction This evaluation supports a proposal to (1) increase the combined leakage rate allowed for all penetrations identified as secondary containment by-pass leakaqe paths, and (2) increase the limit on outside air intake into the control room during the recirculation mode of operation. The sought after bypass leakage rate of 27'A was previously evaluated in Appendix 6B of the FSAR. The reevaluation discussed herein is based on a more conser-vative containment modeling technique. The current limit on control room outside air intake is based on the original control room post-LOCA habit-ability evaluation that is presented in FSAR section 15.4.1.2.5(d). The evaluation did not take credit for the operation of the "backfitted" Iodine Removal System (IRS) and Shield Building Ventilation System (SBVS) heaters. The reevaluation discussed below uses the same control room models and assumptions presented in the FSAR in addition to the operation of the "backfitted" systems.

II. Discussion The St. Lucie Unit 1 calculations estimating whole body and thyroid doses from a postulated loss of coolant accident (LOCA) have been revised. The revised analysis uses a more conservative containment release model. The analysis was previously presented in Appendix 6B of the FSAP, and was based on a single volume well-mixed containment activity release model as well as the "backfit", containment bypass fraction of 27K. The difference between the FSAR analysis and the analysis described herein is that a more conser-vative two compartment containment model is used that takes into account the difference in iodine scrubbing effectiveness between the regions of the con-tainment that receive or do not receive spray coverage. The volume of the containment atmosphere that is sprayed is conservatively assumed to be 86/.

i'lixing is assumed to occur between the sprayed and unsprayed regions at a rate of 4 volumes of unsprayed region per hour. The only other change in assumptions from those presented in Appendix 6B of the FSAR is that it takes 44 minutes for the sprays to reduce the elemental iodine concentration in the containment by the allowable factor of 100 rather than the previous period of 28 minutes. The removal of particulate iodine by the sprays is terminated at 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The pH of the sodium hydroxide solution at the spray nozzle will be between 8.5 and ll. The revised offsite LOCA doses are pre-sented in Table l. Although the revised thyroid doses for both the exclu-sion zone boundary and low population zone are somewhat higher because a more conservative model was used, they are still well within the 300 rem limit set by 10 CFR 100 for the reactor siti ng cri teria.

In the process of developing revised offsite LOCA dose calculations, it was determined that Technical Specification leak testing criteria could be made less stringent. The current Specifications set a 12" limit on unfiltered

,0 0 SAFETY EVALUATION (Continued) secondary containment bypass leakage and a 100 CFH limit on Control Room in-leakage. The revised LOCA analysis discussed above justifies a containment bypass leakage of up to 27% and a control room inleakage of up to 450 CFH.

The LOCA doses presented in Table 1 are based on a bypass leakage of 27'A and the more conservative containment model. All other FSAR assumptions have been retained, The revised 30 day post-LOCA control room doses are presented in Table 2 and are compared to those presented in the FSAR. The control room dose model used in the reelevation is identical to the model described in chap-.

ter 15 of the FSAR. The only change in assumptions is that the IRS and SBVS heat "backfits" have been incorporated and the containment bypass leakage in-creased to 27~ value. Control room inleakage is conservatively limited to 450 CFH. This maximum value of inl eakage, plus the Control Room air conditioning System, assures that the relative humidity of the air at the inlet of the con-trol room's charcoal filters is less than 70/, Relative humidity must be main-tained below this value in order that the assumed charcoal efficiencies presen-ted on FSAR page 15.4.1-20d can be obtained.. The effect of a postulated chlo-rine release on the control room habitability was also reevaluated. The chlorine release evaluation illustrated a value for inleakage of 568 CFtl which is above the limitation imposed by the relative humidity requirements.

III. Conclusion Me have concluded, based on the considerations discussed above, that: (1) the amendment does not involve a significant increase in the probability or con-sequences of accidents previously considered and does not involve a significant decrease in a safety margin, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Com-mission's regulations and the issuance of this amendment will not be inimical to the common defense and securi ty or to the health and safety of the public,

TABLE I REEYALUATION OF FSAR OFFSITE LOCA DOSES FOR 27'A SHIELD BUILDING BYPASS LEAKAGE

~FSAR *~ANENDt1ENT 2 Hour Thyroid- Dose at 1555 Meters (EZB) 66 rem 75 rem 2 Hour Mhole Body Dose at 1555 fleters (EZB) 4 rem 4 rem 30 Day Thyroid Dose at 1609 tIeters (LPZ) 150 rem 167 rem 30 Day i<hole Body Dose at 1609 Meters (LPZ) 5.5 rem 6 rem

• Post iodine removal systems backfit case per FSAR Appendix 6B at page 68-17.

• • Post Iodine removal systems backfit case per FSAR Appendix 6B with addition-al calculational conservatisms as noted in text.

TABLE II REEVALUATION OF FSAR CONTROL ROOM LOCA DOSES FOR THE POST IODINE REMOVAL'YSTEMS BACKFI'T CASE LIITH 450 CFM INLEAKAGE "FSAR'0

• • At1EIIDMENT Control Room Thyroid Dose rem 12.5 rem Control Room (!hole Body Dose 1.7 rem 3.0 rem Control Room Skin Dose 17.8 rem 27.0 rem

• FSAR case at page 15.4.1-20d with no credit for iodine removal system backfits and 100 CFM control room inleakage.

~*Post iodine removal systems backfit case with additional calculational conservatisms as noted in text and 450 CFM control room inleakage.

STATE OF FLORIDA )

) ss COUNTY OF DADE )

Robert E. Uhrig, being first duly sworn, deposes and says:

That he is a Vice President of Florid'a Power 5 Light Company, the Licensee herein; That he has executed the foregoing document; that the state-ments made in this said document are true and correct to the best of his knowledge, information, and belief, and that he is authorized to execute the document -on behalf of said Licensee.

Robert E. Uhrig t

Subscribed and sworn to before me this

~SCIBQ Or A i l~

NOTARY PUBLX , in and for the county of Dade, State of Florida Notary Pubgc, State ot Florida at Largo My Commis"'on Expires October 30, >>1983 lory COmmiSSiOn eXpireS: ~ended tbru Maynard Eonding Agency

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