ML20207G984

Safety Evaluation Supporting Amends 79 & 70 to Licenses DPR-77 & DPR-79,respectively

ML20207G984
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Site:	Sequoyah
Issue date:	08/15/1988
From:	NRC OFFICE OF SPECIAL PROJECTS
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UNITED STATES

+f NUCLEAR REGULATORY COMMISSION c

g 5'

1 C WASHINGTON. D. C. 20555 o

SAFETY EVALUATION BY THE OFFICE OF SPECIAL PROJECTS SUPPORTING AMENDMENT NO. 79 TO FACILITY OPERATING LICENSE NO. OPR-77 8

AND AMENDMENT NO. 70 TO FACILITY OPERATING LICENSE NO. OPR-79 TENNESSEE VALLEY AUTHORITY l

SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328

1.0 INTRODUCTION

By letter dated Jur.e 20, 1988, the Tennessee Valley Authority (TVA) has requested a change to the Sequoyah Units 1 and 2 (SON) Technical Specification 3/4.7.5 regarding the Ultimatt Heat Sink (VHS) reservoir water level and temperature limits.

The present limiting condition for operation (LCO) is 83*F as measured in the Essential Raw Cooling Water (ERCW) supply header. TVA proposes to increase the Li.0 to 84.5 F.

TVA also proposed an LCO on river water level of 670 ft. msl.

In addition, TVA proposed that the wording of LC0 3.7.5 and surveillance requirement (SR) 4.7.5 be modified to clearly specify that the UHS temperature limit applies to the ERCW supply header water temperature, the action statement and surveillance requirements (SR) for LCO 3.7.5 be modified to be consistent with the proposed addition of the LC0 for the reservoir water level, and the bases for TS 3.7.5 be modified to reflect these changes.

The reason for this change is that the reservoir water temperatures at the plant above Chickamauga Dam are running considerably higher than normal because of extended drought conditions.

It is T"A's position that the proposed 1.5 F change in the LC0 will allow continued plant operation throughout the summer without affecting the ability to safely shut down the plant under

, design basis conditions.

This amendment also deletes the current SR a.7.5.2 for Unit I to resolve a clerical error by the staff, as described belcw.

SR 4.7.5.2 was removed from the Unit 1 TS in Amendment 8 dated July 15, 1981.

The recuirement was removed because the ERCW pumping station eliminated the plant's dependence upon the intake forebay and SP 4.7.5.2 was no longer needed.

The Safety Evaluation for Amendment 8 stated that Section 9.2.2 of NUREG-0011 which licensed Sequoyah acknowledged that the ERCW purping station was designed and located to eliminate the decendence upon the intake forebay.

Therefore, the surveillance on components of the makeup water system and the forebay portable makeuo cump and drives were not needed.

TVA stated in a telephone conference call on August 11, 1988 that this equipment no longer exists at the plant.

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. In Amendment 12 dated March 25, 1982, SR 4.7.5.2 was inadvertently reissued by the staff. However, because the ERCW eliminated the plant's deper' nce upon the intake forebay, the equipment no longer exists and the surveillance requirement was inavertently reissued, the surveillance requirements should he deleted from the TS.

TVA stated in the telephone call on August 11, 1988 that it had requested by letter dated July 22, 1982 that the Staff reissue the TS 3/4.7.5 which was issued in Amendment 8.

The staff has researched the amendments issued on TS 3/4.7.5 and concludes that the valid TS 3/4.7.5 is that one issued in Amendment 8.

Based on the above, the staff concludes that SR 4.7.5.2 was inadvertently reissued in Amendment 12 after being deleted in Amendment 8.

Therefore, SR 4.7.5.2 will be deleted from the Unit 1 TS.

2.0 EVALUATION 2.1 Backoround The UHS for Sequoyah is the Tennessee River Reservoir above the Chi kamauga c

Dam.

The Chickamauga Dam is not considered to be capable of serving the plant during either the design t~ sis flood or the design basis earthquake.

Hence, i

TVA has considered the declining water level of the UHS af ter failure of Chickamauga Dam along with the transient heat load conditions of either unit after an accident.

The current 83*F water temperature limit was developed during the initial licensing of Sequoyah.

It represented a maximum river water temperature measured over a 25-year period, with all otber maximum temperatures measured at below 80 F.

The LC0 of 83 F was coupled with the assumption that, in the event of downstream dam failure, the water level in the reservoir would drop instantaneously from an operating level of over 675 ft, msl to a minimun level of 636 ft. nsl.

The immediate reduction of available Net Positive Suction Fead (NPSH) on the pumps would mean an imme<!iate reduction in available flow from the ERCW pumps.

The ERCW is the system between the UHS for Sequoyah and the safety-grade dooling systems for the plant. The ERCW is described in Section 9.2.2 of the SON Final Safety Analysis Report (FSAR).

The system services the essential plant heat loads that exist for both normal plant operation and for accident mitigation.

2.2 UHS Water Temoerature Evaluation TVA stated in its application that the criginal calculated EPfW flows were for a water level of elevation (el.) 626 ft. rean sea level (msl) and were based on design assumptions that did not reflect as-built plant conditions.

TVA has recalcuhted ERCW flows for the fcntainment Soray (CSI and component Coolina System (CCS) flews based on a reservoir level of el. 670 ft. msl.

TVA

.iustified this en the basis that the primary heat leads on the CS and CCS systens would occur early in the Loss-of roclant Accident (LOCA) when the water level may be expected to be above el. 670 ft. nsl.

Figure 14 in the

• application shows the Chickamauga Reservoir drawdown at Seouoyah in terms of water level elevation and time following the postulated failure at the dam.

From Figure 9.2.2-21 of the SQN FSAR, it can be seen that the LOCA heat rejection rates to the CS and CCS systems fall off sharply after about 3.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> into the accident and decrease by about one third by 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the accident. By the end of 30 days, CS and CCS heat rejection rates have dropped by more than 70", and are only slightly greater than the constant heat rejection rate of the station auxiliaries.

According to TVA's submittal, the decrease in water level from el. 670 to el. 636 ft. will result in a 7" reduction in available ERCW flow.

If the reservoir water temperature is 83 F and the water level stays above el. 670 ft.

nsi for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, the increase in the long term temperature profile inside the containment after about two days will be about 3 F over the maximum temperature in the FSAR Chapter 6 analysis.

Current prnjections by TVA indicate that a maximum river temperature of 84.4 F in the reservoir above Chickamauga Dam may be reached this summer.

Therefore, TVA has proposed that the LC0 on reservoir temperature be changed to 84.5'F to be consistent with the original basis for the maximum UHS water temperature.

TVA has evaluated the effect of elevated UHS temperature on the FSAR Chapter 6 analysis.

TVA has concluded that the effect of elevatino the UHS temperature to 84.5 F will result in an increase of 1.5 F for temperatures inside containment.

For the combined decrease in flow and increase in temperature, TVA has estinated a maximum long term temperature inside the containment of 4.5'F over the FSAR Chapter 6 analysis.

The change in tha UHS temperature potentially affects the heat removal rate from many areas c the plant.

In order to demonstrate the acceptability of the proposed change. TVA stated that it has performed an evaluation of the effect of the increased temperature on the following key plant analyses:

Emergency core cooling system (ECCS)

Other FSAR Chapter 15 accident analyses Containment subcompartment pressure analysis Peak containment temperature Peak containment pressure Lono-term containment cooling Long-term cooling for pipe breaks outside centainment Equipment cualification (EQ) temperature profiles 2.2.1 ECCS Analysis, The primary function of the ECCS is to cool the reacter core by removing stored and fission product decay heat from the reactor core so that fuel rod damage remain! within prescribed limits.

The reouirements for ECCS evaluation mocels are described in 10 CFR 50, Appendix K and 10 CFR 50.46.

4 The FSAR accident analyses, which demonstrate compliance with the reouirements of 10 CFR 50,46, show the pesk clad temperatures and core reflood/ quenching occur The peak many minutes before any heat removal from the core to the UHS begins.

cladding temperature occurs at approximately 180 seconds into the ECCS event Heat removal to the UHS does and core reflood is completed around 500 seconds.

not occur until switchover of the Residual Heat Removal (RHR) system from the Refueling Water Storage Tank (RWST) to the emergency sump at approximately 1600 seconds.

Because the parameters that demonstrate compliance to 10 CFR 50.46 are not affected by an increase in the UHS temperature, TVA stated that the FSAR ECCS analyses (FSAR Sections 15.3.1 and 15.4.1) will not be changed.

2.2.2 Other FSAR Chaoter 15 Analyses The remaining FSAR analyses for Condition III and IV faults address transients l

and accidents that may cause core overcooling or overheating from reductions in

)

shutdown margin, excessive or insufficient heat remeval, or loss of or change in fcrced reactor coolant system (RCS) flow.

Condition I and II events were not addressed because theso conditions represent either normal operation or operational transients or faults of moderate frequency that, at worst, result in reactor shutdown with the plant Leing capable of returning to operation.

These other events which are addressed in the FSAR are the following:

I 1.

Major or minor secondary system ruptures (FSAR Sections 15.3.2 and 15.4.2).

2.

Complete loss of forced RCS flow cr single reactor locked rotor (FSAR Sections 15.3.4 and 15.4.4).

3.

Rod cluster withdrawal at full power (FSAR Section 15.3.6).

i 4

Rod cluster control assembly ejection (FSAR Section 15.4.6).

5.

Staam genera a r tube rupture (F5AR Section 15.4.5).

6.

Fuel handling accident (FSAR Section 15.4.5).

7.

Waste gas decay tank rupture (FSAR Section 15.3.5); and 8.

Inadvertent loading of a fuel assembly into an imprcper location (FSAR Section 15.3.3).

The first four events listed above do not depend upon heat removal to the UHS for mitigation of the consecuences that occur early in the event.

TVA stated that, therefore, the FSAR analyses fer these events will not be altered by the proposed change.

TVA stated that the the consequences associated with a steam generator tube rupture (SGTR) will not be altered by the proposed change.

However, the last mitigative action item listed fnr the operator in the FSAR analysis for an SGTR is initiation of RHR for cooldown.

The RHR heat cychanger oces transfer its heat load to the UHS via the CCS.

Therefore, ccoldown of the RCS may be slightly extended but the extended cooldown does not represent any uracceptable consecuences.

The consequences of the waste gas decay and fuel handling accident are not affected by the proposed change.

The inadvertent loading of the fuel assembly into an improper location dees not impact heat transfer to the UHS.

B 2.2.3 Subcompartrent Pressure Analysis TVA stated that the peak subcompartment pressures given in the FSAR will not change because of an increase in UHS tempera +ure.

In order to maximize pressure, the subcompartment pressure analyses in FSAR Section 6.2 assume an instantaneous, double-ended guillotine rupture of the largest pipe within a The resulting flow because of the rapid depressurization given subcompartment.

of the pipe or system produces the peak subcompartment pressure in a matter of seconds.

No heat removal to the UHS is assumed in the FSAR analyses.

Therefore, they are unaffected by changes in UHS temperature.

2.2.4 Peak Containment Te.mperatures The peak containment temperature results from a main steam line break (MSLB) and occurs very early in the transient during blewdown from the faulted steam generator.

During this period, increases in containment temperature and pressure are mitigated by the ice condenser, the CS, and passive heat sinks.

The CS systen is supplied with constant temperature water from the refueling water storage tank (RWST) without any heat removal by the CS heat exchanger to the UHS. The mass and energy releases from the faulted steam generator to the containment are terminated by steam generator dryout within 30 minutes (even for small breaks). The ice bed does not melt out until many hours after an MSLB and continues to remove energy from the containment.

By the tire switchover of the CS system to the emergency sump occurs and heat removal to the UHS begins, temperatures in containment have been decreased substantially because of heat removal from flow through the ice condenser caused by the air return fans.

Thus, peak containment temperatures will not be affected by the proposed changes because heat is not transferred to the UHS during the time of peak centainment temperature.

Peak Containment Pressure The peak containment pressure is a result of a large-break LOCA.

During a large-break LOCA, heat transfer from containment to the UPS begins at approximately 1600 seconds via tne couoled RHR and CCS heat exchangers.

Thus, the containment temperatures and pressures predicted in the FSAP analysis for a design basis LOCA before 1600 seconds will net change regardless of the UPS temperature.

TVA stated in its application that, after RHR switchover to the emergency sump at 1600 seconds, the temperature of the injection flow to the core is affected by the proposed change.

The increased core inlet temperature would result in a slight increase in mass release to containment from core bofloff.

However, containment conditions are still controllec by the CS system, air return fan, and ice condenser; and the design basis containment analysis presented in the FSAR is not significantly impacted.

The CS beat exchanger system begins to i

J transfer its heat to the UHS at approximately 2800 seconds followino switcbover from the RWST to the crergency sump.

But until ice condenser bed meltout at approximately 3000 seconds, switchover of the containment spray does not appreciably change the FSAR analysis.

Following ice condanser bed meltout, the

. At pressure and temperature in the containment begin to increase noticeably.

3600 seconds, the RHR spray is initiated to increase the total containment beat removal capability. The containment pressure continues to increase until the heat removal to the UHS via the RHR and CS heat exchangers and through the containment shell exceeds heat addition to the containment atmosphere.

In order to quantify the effect on containment peak pressure because of a change in the UHS temperature, TVA stated that it performed a series of containment analyses using a MONSTER model benchmarked against the FSAR design basis analysis.

The benchmark analysis was performed using the FSAR Chapter 6 model and associated data (i.e., volumes, flow paths, ice weight, and heat sinks),

blowdowns, pump flows, and UHS temperature of 83 F.

The heat exchancer parameters from FSAR Section 9.2.2.2 were used in this analysis for the CS, CCS, and RHR heat exchangers. A peak pressure of 11.03 pounds per square inch 2

The FSAR peak gauge (lb/in g) was calgulated for the lower compartment.

pressure is 11.09 lb/in g calculated with the LOTIC containment code.

The difference between the two codes is less than 1 percent. Using 85'F as the UHS temperaturg increased the peak lower compartment pressure by approximately 0.13 lb/in g.

The distribution of flows in the ERCW has been revised by TVA since the FSAR analysis was performed. A new containment analysis was performed usino tbc FSAR mocel but with measured flow rates and revised heat exchanger ccefficients for CCS, CS, and RHP heat excoangers.

The containment analysis shows that the 2

pressure profile predicted by the analysis (peak pressure 10.91 lb/in g) was bounded by the design basis FSAR analysis.

TVA stated that, in order to ensure that the heat removal from containment is conservatively modeled, the ERCW flow rates to the heat exchangers were reduced by 10 percent.

A containment LOCA analysis using the revised ERCW flows (with a 10-percent margin reduction), 83*F UHS temperature, and heat exchanger duties was performed by TVA.

TVA stated th.3t the peak pressure for the lower comoartment in this analysis was 11.36 lb/in"g and a parametric study of this mee

, using an 85*F UHS temperature,2 increased the peak lower compartment pressur ey deproximately 0.14 lb/in g to 11.50 lb/in'g.

The results of these analyses showed that the design basis LOCA analysis with an 85*F ultimate heat sink temperature does not exceed the containment design pressure of 12 lb/in#g.

Thus, TVA stated that the peak containment pressure will net be unacceptably increased by the proposed change. The staff agrees with this conclusion, 2.2.5 Lona-Term Containrent Coolino s

long-tern cooldown involved in recovery from a postulated accioent scenarin or normal cooldown with the PHR system will involve heat transfer to the UHS and therefore, any increase in the UHS temcerature will decrease the rate of cooldown.

Because heat is transferred to the UHS via heat exchangers with given duties based on specified temperature differentials, heat removal would not be changed if the source tercerature (i.e., CS and PFC and ultimately the containment atrospherel increased by the same amount as the sink temoerature

. (assuming that the heat exchangers are 100 percent efficient).

Therefore, for an increase of 1.5'F in the UHS temperature, an increase of 1.5 F can be expected (in the limit) in the source temperature profile.

Therefore, t.

ing this rationale, the lower compartment coolers that are initiated within four hours after a postulated MSBL would remove less energy from containment than predicted by the current analysis yielding a contairrent temperature increase of 1.5'F.

Also, during a design basis LOCA, the CS and RHR heat exchangers would not remove the energy predicted in the FSAR analysis unless the containment temperature eventually increased in the limit by 1.5 F.

Therefore, the long-term containment temperature profile can be expected to increase by a j

maximum of 1.5*F as a result of the proposed change. The increased temperature will extend the predicted amount of time required to reach normal temperature provided that the elevated temperatures exist for the entire cooldown period, TVA stated chat historical data on river water temperature at the ERCW pump j

intake indicates that this is extremely unlikely.

TVA stated that the long-term containment cooldown for the proposed 84.5'F will i

also be affected by the postulated loss of downstream dam assumed concurrent with the design basis LOCA.

TVA explained that the postulated dam failure will result in a reduction the total flow capacity of the ERCW system.

The total ERCW flow capacity at normal reservoir levels (see FSAR Figure 7.d.1.3, Sheet 1 of 14) is greater than cesign flows used in the containment analyses and will remain so for approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> after the postulated LOCA and dam failure.

After approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, the reservoir level will drop baiow the 670 foot level used to determine ERCW design flow rates for the various analyses.

The reservoir level will stabilize at the minimum level in approximately two days, causing a 7 percent reduction in the total ER::W flow rate.

Tha 7 percent fIcw reduction would cause a decrease in the heat removal capability of the ERCW system and would result in increases on the order of 3*F in the long-term containment temperature after two days.

Therefore, in conjunction with the increased river water temperature, the long-term terperature inside containment would increase oy no more thaa 4.5 F starting at two days after the accident and continuing through the remaining duration of the accident.

The increased long-term cont?.inment temperature will affect the qualified post-accident degradation equivalency calculations for '.0 f.FP 10.49 equipment.

fhis effect is addressed in Section 2.2.7 5elow on EQ Temperature Profiles.

Ne other parameters are affected by the increased icng-term containment temperatures.

2.2.6 Lono-Term Coolina for Pipe Breaks Outside Containment Long-term cooling for pipe breaks outside containment is affected by an l

increased UHS temperature because the UHS serves as the uoling water supply l

for ESF room coolers and cocling water tecperature cominates the performarce of the room coolers. TVA stated that the performance of the FSF room coolers was receled assumina a maximum UHS temperature of P4.5"F.

The evaluation u s to determine if the coolers would maintain their respective areas at or below the 100 day post-accident average Environmental Qualification (EM temperature.

TVA's applicaticn provided a tyoical prof 11e of the time varying river and rerm temperatures which TVA states is based on a 10-year averace crofile normalized to the worst-case UHS temperature of F4.5'F.

A typical room temperature profile is also shcwn against the 100-day FO temperature, which is assumec to mm.

imm.

.i.

.pmm.m

, remain constant.

TVA stated that evaluations of the profiles indicate that the 100 day average temperature profiles are not exceeded.

2.2.7 E0 Temperature Profile In regard to pipe breaks outside containment, the staff had questions concerning the typical room temperature profile relative to the 100 day environmental qualification (EQ) temperature and the methods used by TVA to ensure the qualification of recuired safety-related ecuipment.

The st6ff discussed this with SQN personnel, and was informed that the qualification was based on assuming a maximum temperature value (115 F for the example in Figure 13 of the TS submittal) for the areas of consideration. This temperature was assumed by TVA for the entire 100 day period for calculating equipment degradation in determining plant equipment qualification.

For the TS change, TVA calculated new area temperatures and the new averages for the 100 days. In all cases, TVA found the averages to be equal to or below the assumed temperatures used for calculating degradation for equipment qualification. However, since comparison of numeric averages is not considered valid for determining equivalent equipment degradation, TVA determined new equipment degradation values in the cases where new temperatures exceeded the assumed temperatures used for establishing equipment qualification previously.

The new degradation values considered the temperctures which exceeded the previously assumed values.

Except for four cases, the new degradation values were equal to or below the previous values and TVA considt ed the eouipment to be cualified for operation durino the 100 day period.

For these four cases, TVA increased the ERCW flow te fcur room coolers and made changes to the EQ binders to reflect adequate cualification of the equipment.

TVA stated that they were able to gain this extra flow (approximately 12 gallons per minute total) by balancing flow require.ents during the 100 days and taking advantage of the lake elevation being at 670 feet initially dtiring the outside containment pipe break event and prier to the lake reaching an el, of 636 feet for e downstream dam break.

TVA stated that they had calculations to support the availability of water and the assumptions made.

Even though TVA increased the cooler flows as described aL ve for the enuipment located in the above areas, qualification was not established for the 100 days.

Therefore, new equipment degradation calculations were required and put in the plant oualification binders to demonstrate adequate cualification for the

)

affected equipment with the increcsed cooler flows.

Based on the new I

calculations, TVA was able to establish qualification of the equipment for the l

/

required 100 days, 2.2.8 Conclusion I

Based on the staff's review of available information ard discussions with TVA, the staff finds the handling of this specific issue to be acceptable to succort the proposed TS change.

.. In Licensee Event Report (LER) 87-037-1 dated March 10, 1988, on Sequoyah Units 1 and 2, TVA stated that the corrective actions in the LER "will ensure that the subject ESF coolers provide adequate cooling as long as the ultimate heat sink temperature remain belows its 83 degrees F " TVA stated in the telephone call on August 11, 1988 that the engineered safety feature (ESF) coolers which are the subject of the LER were included in the calculations submitted in its application dated June 20, 1988 for the proposed TS change 88-21.

The staff concludes that, based on the above, the results of the analyses presented by TVA justify an increase in the LCO on river water temperature to the proposed 84.P F.

Therefore, the propused TS change for the UHS maximum temperature is

'eptable.

2.3 UHS Water la i Evaluation Based on the discussion in Section 2.2 above on the UHS water temperature, the staff concludes that the proposed minimum UHS water level of el. 670 msl is not consistent with the UHS water temperature of 84.5'F.

It is consistent with the VHS temperature of 33'F.

This is discussad further below.

TVA's analysis is based on a river water elevation of 670 ft. during the initial part of the LOCA.

This is based on the assumption that at least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> would be available for pumping with the water level over el. 670 ft. msl.

Ten hours is based nn a dam failure occurring at the operating pool level of el. 681 ft, ms1.

A figure of reservoir water level versus the months of the year is given 1n the calculation anclosed with TVA's application dated June 20, 1988. The pool elevation may vary between el. 675 and 682.5 ft. for hydropower generation with the icwer elevations being less likely but still possible.

If a dam failure is assumed to occur at el. 675 ft msl, the water level may drop to el. 670 ft, msl in just over 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

This is not consistent with the proposed action statement for the minimum reservoir water level where the plant would be in Hot Standby (Mode 4) within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown (Mode 5) within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

The licensee has an Abnormal Operating Instruction (A0I-22) which reaufres initiation of shutdown when the water level reaches el. 675 and failure of Chickamauga Dam is confirmed at the TVA load center.

This A0I, however, does not require plant shutdnwn at low reservoir water levels which are not associated with a dam failure such as for the preflood season storage.

This drawdown, however, wculd only be expected during the winter.

Based on TVA's application, the river water elevation consistent with an UHS water temperature of 84.5 degrees F is a minimum of 680 ft.

Therefore, TVA's proposed reservoir water elevation of 670 f t. is acceptable

1. or the current water terperature of 83*F and a ress voir water elevation cf 680 ft. is acceptable for TVA's propcsed itHS water temperature of E4.5*F.

This is a small change from the application made by TVA and the Notice of Consiceration of issuance of an amendment in the Federal Fecister en sly 1,1988 (53 FR 250E3).

In a telephone conference on Aucust 11, '988, i

TVA agreed to the above relationship between river water elevation and terperature.

. 2.4 Location To Measure The UHS Water Tercerature The current TS 3.7.5 states that the ERCW system suction is where the water temperature is measured.

The proposed TS change states that the temperature is measured at the ERCW supply header.

TVA stated that the reservoir water temoerature is measured with instru.nentation instelled in the ERCW intake str.cture because this represents the temperature of the ERCW cooling water to the critical heat exchangers. The staff has reviewed the ERCW and concludes that TVA's statement is correct. Therefore, the prnposed change is acceptable.

2.5 Action Statement For LCO 3.7.5 TVA has proposed to revise the action statement for the UHS so that the statement would include provisions for actions required to be taken for unacceptably low reservoir water levels.

The proposed actions for plant shutdown are the same as the current TS.

Therefore, the staff concludes that the proposed TS change is acceptable.

2.6 Surveillance Recuirements It TVA has proposed to keep the current SR 4.7.5 for the water temperature.

TVA did has proposed to verify the reservoir water level once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

not provide a justification for applying the current 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> surveillance period for water temperature to water level.

Based en the staff's review of TVA's application including the Abnormal Operating Instruction A01-22 and because there is no current requirement in the TS to verify the UHS water elevation, the staff concludes that the proposed change is acceptable.

The TS 3/4.7.5 refers to the "average" ERCW supply heater water temperature.

This tercerature may be averaged over a period of not more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This is consistent with the NRC Standard Technical Specifications for this specification.

2.7 Bases For TS 3.7.5 The staff has reviewed the proposed chances by TVA to the bases for TS 3/4.7.5.

The staff concludes from its review of TVA's application that the proposed chances to the bases are correct and, therefore, acceptable, 2.8 Conclusion Based on the above, the staff concludes that the proposed chances to TS 3/4.7.5, Ultimate Feat Sink, in TVA's application TS 88-21 dated June 20,19EC are acceptable for the maximum allowed UHS water temperature in that the units will have the proposed minimum allowed river water elevation of 67C ft. for the current VHS water temperature of 83 cegrees F and will have a mimimum allowed river water elevation of 6E0 ft for the proposeo UHS water temperature of 84.5:F.

.. We have a concern about ERCW availability which is not related to the proposed Technical Specification change. The concern is about erosion and deposition of sediment as a result of high water velocities around and upstream of the ERCtl intake structure as a result of the failure of Chickamauga Dam.

'. is our understanding that these issues were evaluated by TVA but never reviewed by NRC.

In order to make an independent evaluation, we will request from TVA a copy of the topographical cross sections plotted for the unsteady flow analysis, time varying water velccities in the cross sections near the ERCW, geologic cross sections through the reservoir, and the sediment scour and deposition calculations.

3.0 ENVIRONMENTAL CONSIDERATION

These amendments involve a change to a reouirement with respect to the installation or use of a facility component located within the restricted area The as defined in 10 CFR Part ?0 and changes to the surveillance requirements.

staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.

The Comission has previously issued a proposed finding that these amendments involve no cignificant hazards consideration and there has been no public comment on such finding.

Accordingly,theamendmentsmeettheelio{ibilitycriteriafo-categcrical exclusion set forth in 10 CFR 51.22(c')(9.

Pursuant to 10 CFR 51.22(b), no i

environmental impact statement nor envircamental assessment need be prepared in connection with the issuance of these amendments.

4.0 CONCLUSION

We have concluded, based on the considerations di cussed above, that: (1) there is ressorable assurance that the health ano safety of the public will not be endangered by operation in the propo:ed tranner, and (2) such activities will be conducted in compliance with the Comrrission's regulations, and the issuance of these amendments will not be inimical to the common de'ense and security nor to the health and safety of the public, i

o Principal Contributors:

R. Wescott, G. Hubbard, J. Donohew Dated: August 15, 1983

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