ML17325B781
| ML17325B781 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/18/1987 |
| From: | Grimsley D NRC OFFICE OF ADMINISTRATION (ADM) |
| To: | Devine T, Dixon C GOVERNMENT ACCOUNTABILITY PROJECT |
| Shared Package | |
| ML17325B782 | List:
|
| References | |
| FOIA-84-741, FOIA-84-742, RTR-NUREG-0588, RTR-NUREG-588, RTR-REGGD-01.054, RTR-REGGD-1.054 2.206, NUDOCS 8703200214 | |
| Download: ML17325B781 (19) | |
Text
EMERGENCY CORE COOLING SYSTEMS SURVEILLANCE RE UIREHENTS Continued 2.
At least once per 18 months.
Bor on Injection Throttle Valves Valve Number 1.
2-SI"141 L1 2.
2-S I-141 L2 3.
2-S I-141 L3 4.
2-SI"141 L4 Safety Injection Throttle Valves Valve Number 1.
2"SI-121 N
2.
2-5 I-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 gpm 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 mini flow, shall not exceed 700 gpm.
"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 flow) branch 1 ines.
I'.
C.
COOK - UNIT 2 3/4 5-6 Amendment No.
g 'h
'k
SPECIAL TEST'XCEPTION POSITION INDICATOR KENNELS SHUTDOWN LIMITING CONDITION FOR OPERATION 3.10.5 The limitations of Specification 3-1 ~ 3.3 may be suspended during the performance of individual full length (shutdown and control) rod drop time measurements 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Only one shutdown or control bank is withdrawn from the fully inserted position at a time, and b.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 time measurements.
ACT10N tlith the group demand posit'on 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 determined 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. Denton AEP:NRC:0860A ATTACHMENT 4 TO AEP:NRC:0860A
<v'ESTINGHOUSE SUPJIARY OF THE SAFETY EVALUATION FOR INCREASED SI PUMP MINIFLON
4'
~ 4 p
c I
LOCA EVALUATION FOR D.
C.
COOK UNIT 2 WITH REDUCED HIGH HEAD SAFFTY INJECTION This evaluation assesses the impact of r educed high head safety injection on ECCS performance in response to a LOCA for the D.
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 total 'afety injection is 5X in the range of 1200-600 psia important for this evaluation.
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 f'r 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:ierfonned 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 sensitivity 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.
Th6 two plants'ydraulic characteristics are nearly identical.
The only significant difference fs Unit 1
has 15x15 fuel and Unit 2 has 17xl7 fuel.
Hut more importantly the difference in fuel assembly. flow areas between the two designs is less than 0.3%.
2.
The effect of r educed HHSI on the transient is hydrau-lic.
Reduction in SI diminishes the effects of boiloff replenishing in 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 SI 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 quas'i-steady state during the clad heatup period.
4.
The small LOCA analysis for Unit 1
was performed at 3411 MWt, 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.
~
~
&3&
This evaluation has assessed the impact of reduced HHSI on the performance of the ECCS at the 0.
C.
Cook Unit 2 plant.
The reduced HHSl 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 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.
TABLE 1 Comparison of Total Safety Injection Flow Delivered to the 'RCS (Includes
- Charging, HHSI and LHSI Where ADDlicable)
RCS Pressure 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 1314.7 510. 7 213. 2 105. 0 103. 0 93.5 84.3 IDo6 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 l REDUCED (60 GPM MINIFLOW)
HHSI EVALUATION
D. C.
COOK 1
REDUCED HHSI SENSITIVITY SHALL BREAK TIME SEQUENCE OF EVENTS (SEC)
EVENT TIME 4
INCII 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 SMALL BREAK RESULTS RESULTS 4
INCH PEAK CLAD TEMPERATURE (oF)
PEAK CLAD TEMPERATURE LOCATION (FT)
LOCAL Zr/H20 REACTION, MAXIMUM (X)
LOCAL Zr/H20 LOCATION (FT)
TOTAL Zr/H20 REACTION (X)
HOT ROD BURST TIME (SEC)
HOT ROD BURST LOCATION (FT) 1716 11.75
- 0. 93 0.3 CALCULATION NSSS Power MWt 102K of peak Linear Power kw/ft 102K of Hot Rod Power Distribution
(
Accumulator Water Volume, cu. ft.
Fuel region
+ cycle analyzed UNIT 1 Cycl e
. 8 3411 15.50 950 Region W FUEL
- SAME COOK UNIT 1 CYCLE 8 RELOAD SMALL BK ANALYSIS
t$00.0 tS00.0 0
C COOK Uhlan l AEP SH QK IH SK REOUCE Sl SEKS 3ill RCS PRESSURE OPSIA 2000.0 l500.0 l000.0
$00.00
~.0 CI 3
3 vs TjHE (SECI RCS PRESSURE - 4IH DIA. CL 8K
TI.000 T2.500 0
C COOV uHIT T
AEP.
SH BK TH SK REOUCE ST SENS 3i !T ORE HE ICHT {FT) 10.000 7.5000 5;0000 t-5000 0.0 Fig.
2 8
8 8
8 I
P TTHE (SEC)
CORE !CIXTURE HEIGHT - 4IN DIA CL BK
lI l e
I j'p
xoo.o 0
C CDDK uxlt I AEP SV SX 4 IH SX AEDUCE SI SESS 31)l CLAD AVC.IEHP.HOI RDO SURSI l2.00 FIl )
PEAK ~ II 7$ FII )
~ 2500.0
~ 2000.0 C
C
)500.0 C
C l000.0 soo.oo 0.0 8
C 8
8 YIHE ISEC)
Fig.
3 HOT SPOT CLAD TEI1PERATurr 4IN BK
%0.00 0
C COOK
- elf l AEP SH SK i lv BK atuuCC Sl SEES lett StCAH Fvou
<tBISKC m %0.00 VI o
100.00 0.0
-l00.00
-200.00
-300.00
-)50.oo 8
Ch Fig.
4
~4 llHE ITIC)
CORE STEAtl FLO';l RATE 4IN BK
Exhibit B of Attachment 1
to AEP:NRC:0916Z March 23, 1984 Letter from M. P. Alexich (1&MECo) to H. R. Denton (NRC) which Transmitted Supplemental Information Regarding Unit 2 Cycle 5
Reload Technical Specifications
V R
4t Ji,'