ML101580445
| ML101580445 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/07/2010 |
| From: | Lin A Nuclear Energy Institute, Pacific Gas & Electric Co |
| To: | NRC/NRR/DSS/SRXB |
| Lyon W, DSSA/SRXB, 415-2897 | |
| Shared Package | |
| ML101580207 | List: |
| References | |
| Download: ML101580445 (10) | |
Text
Simplified Equation Status NRC / NEI Anderson Lin PWROG Technical Lead Diablo Canyon Power Plant NRC / NEI June 2, 2010
PWROG Projects Void Transport (WCAP-16631 for 6 & 8)
On Going 4 & 12 @ Purdue
- Static Pressure
- Buoyancy
- Breaks down
- Transport Buffers Scaling of models Water Hammer
- Pressure Pulsation (OG-08-315)
Pipe Hangers Simplified Gas Transport Equation Pump Interim Gas Ingestion Tolerance Criteria (V-EC-1866)
- Steady State & Transient Void Limits
- Types of Pumps
- Peak / Average Void Fraction
- Momentary TDH Degradation
- NPSHR vs. NPSHA
- Scaling of models p
g Relief Valves
- Hot Recirc. & Containment Spray (OG-08-292)
Non-Condensable Gas into the Reactor Vessel (OG-08-293)
- ECCS Delay
- LOCA & Non-LOCA Qualitative Evaluation
Gas Transport vs. Flow Rate Observation: Higher flow results in higher void fraction (over a shorter duration) being transported
Bounding Condition 1.
Met Most Stringent Void Acceptance Criteria :
{
Highest Flowrate
{
Supported by Conservative Tested Void Condition 2.
PIRT To Minimize The Initial Void Volume
{
Conservatively Limit to 5% (i.e., 11% test) 3.
Minimize The Risk To Pump Operability 1.
Likely Be Implementable at the Plant
Simplified Equation vs. APC Criteria
Simplified Equation vs. DSS & APC 70% < BEP < 120%
10% for 5 Seconds
( 11% initial void & Fr=1.9)
Figure 6 6 inch 5% initial void fraction RIMP2 0.07 0.08 0.09 0.1 BEP < 70% or > 120 %
4.8 gallon Total Void Volume Most Limiting 0
0.01 0.02 0.03 0.04 0.05 0.06 0
5 10 15 20 25 30 Time (sec)
Void Fraction F060 F100 F190 NRR
Methodology Consideration
- 1. Ratio = Q gas / Q mixture
{
Voids Must Mix With Water Results in A Much Lower Void Fraction To The Pump 2.
Different Transport for 4, 6 & 8 and 12 2.
Different Transport for 4, 6 & 8 and 12
{
Due to void size to Pipe X-Section Ratio
{
Void Formation Anomalies
{
Limited to Actual Pump Flow Ranges
Treatment of the Simplified Equation 1.
Suction Headers With Takeoffs
{ Use Simplified Equation to calculate allowable void volume for each individual pump suction
{ Apply the smallest of the allowable void volume to the common suction header 2
Allowable Void Volume < 1/4 Of The Downstream 2.
Allowable Void Volume < 1/4 Of The Downstream Vertical Pipe Volume 3.
Allowable void accounts for static pressure change between high point and pump suction
{ Elevation change must be > 10 feet
Advantages of the Simplified Equation 1.
Simplified Equation is Conservative
{
Limits The Allowable Void Volume
{
Not Likely To Gas Bind The Pump
{
Provides Reasonable Basis for Pump Operability
{
Reasonable Engineering Judgment
{
Reasonable Engineering Judgment
{
Enveloped by DSS / APC Void Criteria
{
Supported by the Purdue Test Data 2.
Simple Method To Determine Allowable Void Volume At Any Pump - All Safety Related Pumps
Status zPurdue Test Report Issued by July 31 zSimplified Report Issued by August 16, 2010 2010 zFuture Work May Relax Void Limit on Common Suction Header