ML17326B106

Proposed Tech Specs Re Flowrate for Flow Balance Test of Safety Injection Pumps

ML17326B106
Person / Time
Site:	Cook
Issue date:	03/15/1984
From:	INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:
Shared Package
ML17326B107	List: ML17326B106 ML17334A518
References
NUDOCS 8403200214
Download: ML17326B106 (17)

Text

EMERGENCY CORE COOLING SYSTEMS SURVEILLANCE RE UIREMENTS Continued 2.At least once per 18 months.Boron Injection Throttle Valves Valve Number l.2-SI-141 Ll 2.2-SI-141 L2 3.2-SI-141 L3 4.2-SI-141 L4 Safety Injection Throttle Val ves Valve Number 1.2-SI-121 N 2.2-SI-121'S h.By performing a flow balance test during shutdown following completion of modifications to the ECCS subsystem that alter the subsystem flow characteristics and verifying the following flow rates: Boron Injection System Sin le Pu Loop 1 Boron Injection Flow 117.5 gpm Loop 2 Boron Injection Flow 117.5 gpm Loop 3 Boron Injection Flow 117.5 gpm Loop 4 Boron Injection Flow 117.5 gpm Safety Injection System Sin le Pumo"" Loop 1 and 4 Cold Leg.Flow>300@pm Loop 2 and 3 Cold Leg Flow>300 gpm**Combined Loop 1,2,3 and 4 Cold Leg Flow (single pump)<640 gpm.Total SIS (single pump)flow, including minif low, shall not exceed 700 gpm.Amendment No."The flow rate in each Boron Injection (BI)line should be adjusted to provide 117.5 gpm (nominal)flow into each loop.Under these conditions there is zero mini-flow and 80 gpm simulated RCP seal injection line flow.The actual flow in each BI line may deviate from the nominal so long as the difference between the highest and lowest flow is 10 gpm or less and the total flow to the four branch lines does not exceed 470 gpm.Minimum flow (total flow)required is 345.8 gpm to the three most conservative (lowest&low) branch lines.84032002i4 8403l5 PDR ADOCK 05000316 P PDR 0.C.COOK-UNIT 2 3/4 5-6 SPECIAL TEST EXCEPTION POSITION XNDXCATOR CHANNELS SKJTDONN LIMITING CONDITION FOR OPERATION 3.10.5 The limitations of Specification 3.1.3.3 may be suspended duzing the performance of individual full length (shutdown and control)rod drop time measuzements provided;a.Only one shutdown or control bank is withdrawn from the fully inserted position at a time, and b.The group demand position indicator is OPERABLE during the withdrawal of the rods.APPLICABILITY:

MODES 3, 4 and 5 during performance of rod drop tlme measurements.

ACTION>lith the group demand position indicator inoperable, or more than one bank of rods withdrawn, immediately open the reactor trip breakers.SURVEILLANCE REQUIREMENTS 4.10.5 Each of the above required group demand position indicator(s) shall be detexmined to be OPERABLE by movement of the associated shutdown or control rods at least 8 steps in any one direction within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to the start of the rod, drop time measurements.

D.C.COOK-UNIT 2 3/4 10-5 Mr.Harold R.Dent-10-AEP: NRC: 0860A~~ATTACHMENT 4 TO AEP:NRC:0860A WESTINGHOUSE

SUMMARY

OF THE SAFETY EVALUATION FOR INCREASED SZ PUMP MINIFLOW LOCA EVALUATION FOR D.C.COOK UNIT 2 WITH REDUCED HIGH HEAD SAFFTY INJECTION This evaluation assesses the impact of reduced high head safety injection on ECCS performance in response to a LOCA for the 0.C Cook Unit 2 plant.W Safeguards Systems performed an independent calcula-tion evaluating the impact to high head safety injection{HHSI)of incmasing HHSI pump miniflow from 30 gpm to 60 gpm.The calculation assumed a 60 gpm miniflow and that each pair of cold legs receives greater than 300 gpm during flow balance testing.The ECCS flowrates were then calculated using the vendor performance curve degraded by 5%of design head.The total delivered safety injection flowrates to the RCS for both 30 gpm and 60 gpm are shown in Table I.The reduction of t'otal'afety injection is-3-5X in the range of 1200-600 psia important for'-this'valuation.

Lar e Break LOCA Im act HHSI pump flow provides an insignificant proportion of the total 6I flow during a large break accident where RCS pressure rapidly drops to near atmospheric.

Accumulator and low head safety injection (RHR)flow are important for this postulated accident.For this reason, small changes in HHSI pump flow have a negligible effect on the large LOCA calculated peak clad temperature.

Small Break LOCA Im act The effect of HHSI'reduction on small break LOCA is determined.

via an analysis with the approved W small break LOCA evaluation model nerformed on the 0.C.Cook Unit 1 plant, which was analyzed at 3411 MWt core power.The calculated PCT increase derived from this LOCA analysis is 86.1'F, calculated on the worst break size.The inclusion of this PCT increase effect to the base PCT of 1668'F (worst break size)for 0.C.Cook Unit 2 yields a value well below the 10CFR50.46 limit of 2200'F and is less limiting than the current worst large break PCT.The sensit'ivi ty of PCT due to small HHSI flow reductions developed with D.C.Cook Unit 1 is applicable and bounding for 0.C.Cook Unit 2 for the following reasons:

1.The two plants'ydraulic characteristics are nearly identical.

The only significant difference is Unit 1 has 15x15 fuel and Unit 2 has 17x17 fuel.Hut more importantly the difference in fuel assembly f1ow areas between the two designs is less tha'n 0.3%.2.The effect of reduced HHSI on the transient is hydrau-.lic.Reduction in SI diminishes the effects of bofloff replenishing fn the core.Thus, small reduction in downcomer level and core mixture height will result.This effect is well behaved and observed through.small LOCA analyses performed for numerous plants studying Sl effects.3.The effect of a reduction in core mixture height in-creases the length of core uncovered and thus the enthalpy rise of the steam.The steam enthalpy at the uncovered elevations determines clad temperature since the transient is quasi-steady state during the clad heatup period.4.The small LOCA analysis for Unit 1 was performed at 3411 MMt, similar to the Cook Unit 2 power.There-fore, the additional enthalpy rise will be calculated correctly.

5.The heat linear generation rate For Unit 1 is greater than Unit 2 due to fewer fuel rods.Therefore, the effect on PCT of reduced HHSI will be maximized.

6.Other conservatisms in the analysis exist.For example, the small LOCA analysis for Unit 2 assumed an Fg of 2.32 while the plant is limited in operation to 2.04 by large break considerations.

This evaluation has assessed the impact of reduced HHSI on the performance of the ECCS at the D.C.Cook Unit 2 plant.The reduced HHSI has a maximum impact of 86.1'F on peak clad temperature for a small LOCA.The inclusion of this PCT increase to the base small LOCA PCT of 1668'F for D.C.Cook Unit 2 yields a value well below the 10CFR50.46 limit of 2200'F and is less limiting than the current worst large break PCT.

Comparison of Total Safety Injection Flow Delivered to the RCS (Includes Charging, HHSI and LHSI Where Applicable)

RCS Pressure SIa 30 ow (1b/s)60 Minx ow 1b/s)14.7 114.7 140.7 214.7 414.7 614.7 814.7 1014.7 1214.7 1314.7 p~510.7 213.2 105.0 103.0 93.5 84.3 73+6 61.9 48.2 39.5 509.3 210.8 103.3 100.,5 91.1 81.4 70.6 59.0 45.4 36.6 APPENDIX OF ADDITIONAL RESULTS FROM THE 0.C.COOK UNIT 1 REDUCED (60 GPM MINIFLOW)HHS I EYALUATION D.C.COOK 1 REDUCED HHSI SENSITIVITY SHALL BREAK TIME SEQUENCE OF EVENTS (SEC)EVENT TIME 4 IlICII START REACTOR TRIP SIGNAL TOP OF CORE UNCOVERY ACCUMULATOR INJECTION BEGINS PEAK CLAD TEMPERATURE OCCURS TOP OF CORE COVERED 0.0 17.5 413.0 800.0 823.3 1310 D.C.COOK UNIT 1 REDUCED HHSI SENSITIVITY

~~St1ALL BREAK RESULTS RESULTS 4 INCH PEAK CLAD TEMPERATURE (oF)PEAK CLAD TEMPERATURE LOCATION (FT)LOCAL Zr/H20 REACTION, HAXIHUM (X)LOCAL Zr/H20 LOCATION (FT)TOTAL Zr/H20 REACTION (X)HOT ROD BURST TINE (SEC)HOT ROD BURST LOCATION (FT)CALCULATION 1716 11.75 0.93 11.75 0.3 NSSS Power MWt 102K of peak Linear Power kw/ft 102K of Hot Rod Power Distribution (Accumulator Hater Volume, cu.ft.Fuel region+cycle analyzed UNIT 1 Cycl e 8 3411 15.50 950 Region'kl FUEL*SAME COOK UNIT 1 CYCLE 8 RELOAD SHALL BK ANALYSIS R$00.0 tS00.0 0 C COOK UNlf l AEP SH BK 4 ls SK RCOUCE Sl SE~S 3all RCS PRCSSURE OPSIA Vl;O.F000.0.ih~~~VI l500.0 y.~l000.0 500.00~.0 4 T Fig.1 TIHE (SEC)RCS PRESSURE-4IH DIA.CL BK II.OOO I2.S00 C COOK Ullll I AEP SH SK IH SK Af DUCf SI Sf NS 3i I I Af HE ICHOR lAi I0.000 ,L l>l~'I 7 5000 R.SOOO 1~r}ll Ck yl:r Jl gl~.0 Fig.2 8.8 8 Ch CI TIHE lSECI.CORE flIXTURE HEIGHT-4IN DIA CL BK

5000.0 D C COOK UNlf l AfP SH BK lN SK RCOUCC Sl SCNS 3ill CLAD AVC.ffHP Nof ROD BURST 12.00 foal l PEAK ll.lS fBel;w 2500.0 h~.'w'2000.0 Ch 4.-g lSoo.o l000.0 soo.oo 0.0 If thh Fig.3 8 C Ch tlHE lSCCl HOT SPOT CLAD TEt1PERATURF

-4IN OK 4$0.00$00.00 0 C COOK.:)IF l AEP SH QK I IN QK.k(tjUCE Sl SENS 311 l SIEAH Flou<LBISEC~%0.00~8 5 o IOO.OO X 0.0-l00.00-200.00-)OO.OO-N0.00 8 Fig.4 lIHE DECI CORE STElN FLO'l RATE 4IN BK

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