ML19210D077

Responds to NRC 791008 Ltr Requesting Description of Proposed Dynamic Loads.Tables Describing Closure Plan Encl

ML19210D077
Person / Time
Site:	Limerick
Issue date:	11/14/1979
From:	Boyer V PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Varga S Office of Nuclear Reactor Regulation
References
NUDOCS 7911200497
Download: ML19210D077 (12)

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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET PHILADELPHI A. PA.19101 V.S.BoYER vics enssiosur NOV 141N9 Mr. S. A. Varga Acting Assistant Director for Light Water Reactors Division of Project Management U.S. Nuclear Regulatory Commission Washir4 ton, D. C. 20555

Subject:

Limerick Generating Stati,n, Units 1 and 2 Docket No. 5c-352 and 50-3.33

Reference:

Letter dated October S, 1979, S. A. Varga +w E. G. Bauer, Jr.

Dear Mr. Varga:

This letter is written in response to the reference letter which requested a description of the unique pool dynamic loads that Philadelphia Electric Company plans to use for analysis of the Limerick contairment.

The construction schedule for our Limerick Plant allows the for the development of more realistic loads than those extremely conservative loads used by the Lead Plants. Philadelphia Electric Company intends to use the "Non-Lead Plant Closure Plan" criteria which were discussed during the recent Mark II - NRC meeting July 24 and 25 At that meetir4, Mark II Utilities described in detail the "Non-Lead Plant Closure Program."

At the conclusion of that meeting, the NRC agreed to accept certain deviations from the October,1978, " Lead Plant Load Definition Report" -

NuReg 0487 The newly accepted NRC positions are documented in the meeting memorandum - C. J. Anderson to S. H. Hanauer dated August 21, 1979 In addition to these deviations, other tasks including the condensation oscillation test, the improved chugging =odel and the lateral lead confirmation work, although not complete at this time, will be part of the "Non-Lead Plant Closure Program". The NRC has agreed to review these tasks based on the schedules previously presented.

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Mr. S. A. Varga NOV 11 $79 The only unique deviatien from the "Non-Lead Plant Closure Program" for Limerick involves the application method of the LOCA air bubble loads.

The task description is included in the attached chart under sections III.B.1 and III.C. This application method is similar to work currently being developed for the new chugging model. To further clarify the closure program, the Mart 21 Owners plan to meet with representatives from the IEC on November 14, 1979 Sincerely, 7

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Attachment 1367 iA0

LIMERICK CENERATING STATION CLOSURE PLAN NUREC - 0487 RATIONALE NRC LEAD PLANT FOR PLANT SCllEDULE/

LOAD OR PilENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCURERTATION I. LOCA Loads A. Submerged Boundary 33 psi overpressure added 24 Psi statically applied Non-Lead Plant March 20, 1979 Loads during Vent to local hydrostatic below to surface below vent to Generic position Letter from G.E.

Clearing vent exit (walls & basemat) surface below vent exit Accepted by NRC

- linear attenuation to pool (attentuate to 0 at pool surface surface for period of vent clearing)

B. Poolswell Loads

1. Poolswell Analy-tical Model a) Air Bubble Calculate by CE poolswell Accept NUREG-0487 Pressure Analytical Model (PSAM) b) Poolswell Calculate by PSAM using Response to NRC Non-lead Plant NED0-21061 Elevation polytropic exponent of 1.2 Question 020.68 Ceneric Position Rev. 3, 6/78 for wetwell air compression issued 6/30/78 Accepted by NRC c) Poolswell Velocity predicted by PSAM Accept NUREG-0487 except Non-lead Plant Accepted by NRC Velocity multiplied by factor of 1.1. analytical velocity used Generic position 7/24/79 Analytical velocity vari- up to max poolswell ation used up to maximum height.

velocity. Maximum velocity applies thereafter up to max. poolswell height.

q,4 d) Poolswell Acceleration predicted by Accept NUREG-0487 Cys Acceleration PSAM N

e) Wetwell Air Calculate by PSAM Accept NUREG-0487 Compression Ch

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f) Drywell Pressure Plant Unique Calculation in Accept NUREG-0487 llistory FSAR Using NEDM-10320 1 of 10

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LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION

2. Loads on Submerged Max. bubble pressure pre- Accept NUREG-0487 Boundaries dicted by PSAM added to hydrostatic below vent exit. Applied to walls up to max, poolswell elevation.

3. Impact Loads a) Small Structures Hydrodynamic loading func- Accept NUREG-0487 tion shall be P(t)=P MA 1/2 (1-COS2#y)withmax.X pressure acting on projected area of structure (P and duration of impahk )( l' )

calculated by NUREG-0487 Appendix D,Section I.A.6.

b) Large Structures Non applicable (no large structures in poolswell zone) c) Grating Calculate for grating with Accept NUREG-0487 except Non-lead Plant Accepted by NRC open are 60% from the analytical velocity used Generic Position 7/24/79 product of pressure differ- up to max. poolswell height.

ential given by Fig. 4-40 in DFFR, Rev. 2 and the total area of grating, multiplied by the factor-j( F,,/D=l+ 1+/0.0064wf)'.

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4. Wetwell Air

___ Compression rs) a) Wall Loads Direct application of PSAM Accept NUREG-0487 calculated pressure due to wetwell air compression b) Diaphragm Calculated by the correla- Accept NUREC-0487 Upward Loads tion defined in NUREG-0487 Appendix D,Section I.A.4 2 of 10

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LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION

5. Asymmetric Load Assume all air is vented 20% of max. bubble Non-Lead Plant March 16, 1979 on half of drywell pressure statically Generic Position Letter from G.E.

periphery and steam is applied to 1/2 of 20% of max.

vented on the other half. the submerged bubble pressure Calculate max. increase boundary with Accepted by NRC

.in air bubble pressure hydrostatic pressure by PSAM and min. increase of zero shall be applied to wetwell wall in a worst case distribution.

C. Steam Condensation and Chugging Loads

1. Downcomer Lateral Loads a) Single Vent Analyses of downcomer Single vent dynamic lateral Non-lead Plant NEDE 24106P Loads dynamic responses to load calculated by Pretech Position Submitted lateral chugging loads Report methodology is used. July 21, 1978 shall be performed for all HEDE 23806P plants during Mark II Submitted Long-Term Program to provide Hovember 20, 1978.

additional confirmation Supplimental that the static load information will specification defined in be subnitted NUREG-0487, Appendix D 4Q 79

,[, Section I.B.1 is con-q ,y servative.

On sj b) Multiple Vent Loads U

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NRC LEAD PLANT FOR PLANT LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION

2. Submerged Boundary Loads a) High Steam Sinusoidal pressure Accept NUREG-0487 Flux Loads fluctuation added to local hydrostatic. Amplitude uniform below vent exit-linear attentuation to zero at pool surface.

4.4 psi peak to peak amplitude, 2-7 Hz frequencies b) Medium Steam Sinusoidal pressure Accept NUREG-0487 as Non-lead Plant June, 1980 fluctuation added to Interim. Additional Generic Position local hydrostatic, frequency ranges being Amplitude uniform below evaluated. Final basis vent exit-linear attentu- to be 4T CO Test results.

ation to pool surface.

7.5 psi peak to peak amplitude, 2-7 Hz frequencies.

c) Chugging Loads

- Uniform Maximum amplitude uniform Task A.16 load improve- Non-lead Plant Condition attentuation to pool sur- ment plus multivent test. Generic Position fact +4.8 psi max. over-pressure, -4.0 psi max.

{( underpressure, 20-30

%J Hz frequency. NRC FSI con-

- cerns must be resolved.

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LOAD OR PIIENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION C) Chugging Loads

- Asymmetric Maximum applitude uniform " "

below vent exit - linear attenuation to pool surface.

+ 20 psi max. overpressure,

-14 psi max. underpressure 20-30 llz frequency, peri-pheral variation of amplitude follows observed statistical distribution with maximum and minimum diametrically opposed.

II. SRV-Related llydrodynamic Loads A. Pool Temperature a) All Mark II plants are a) Accept NUREC-0487 Limits for KWU required to use Quencher and GE Quenc~ners type devices, b) Suppression pool local b) PaPL will submit test b) Identical to PaPL-temp. shall not exceed data to support no Susquehanna 200*F for all plant (local) temp. limit for transients involving quenchers.

SRV operations.

c) Suppression Pool Temp. c) Accept NUREG-0487 Monitoring System is required to assure operation within Tech.

Spec. limits. System will consist of 8 sets of redundant sensors

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evenly distributed j( around the pool and meet criteria give in

_ ,3 NUREC-0487 Appendix D

_- Section II.4.

C7' t_D 5 of 10

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LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION B. Quencher Air a) Mark II plants utilizing a) T-Quencher load predic- b) Identical to 1978 Clearing Loads KWU Quencher use an tive methods presented PaPL-Susquehanna Interim load specifi- in SSES DAR Section 4.1.3 cation consisting of rams-head calculational pro-cedure. Those utilizing the GE four arm Quencher use Quencher load methodology described in DFFR, Rev. 2.

b) Following load cases b) T-Qaencher load predic- b) Identical to 1978 shall be considered: tive method does not PaPL-Susquehnna include load case (4)

1) Single valve discharge for evaluation. It is for first and consecu- bounded by cases identi-tive actuation fled in SSES DAR Sections 4.1.3.1 and

2) ADS valves discharge 4.1.3.2

3) Two adjacent valves discharge

4) All valves discharge sequentially by setpoint group.

5) All valves dishcarge simultaneously and assume all bubbles in phase.

c) The forcing function c) T-Quencher bubble c) Similar to 1978

__, shall include a range of frequency presented PaPL-Susquehanna (ja bubble frequency of 4 to in Limerick DAR Cys 12 Hz for both discharge sa devices. The T-Quencher frequency range may be increased, if required, C7' to include frequency pre-C7' dicted by Ramhead method-ology with 1 50% Margin.

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LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION C. Quencher Tle-Down Loads

1. Quencher Arm Loads a) Four Arm Vertical and lateral N/A arm loads developed on the basis of bounding assumptions for air / water discharge from the Quencher and conser-vative combinations of maximum / minimum bubble pressure acting on the Quencher b) KWU T-Quencher T-Quencher arm loads not T-Quencher arm Identical to 1978 specified at this time. loads presented in PaPL-Susquehanna SSES DAR Section 4.1.2.5

2. Quencher Tie-Down Loads g a) Four Arm Calculate vertical and N/A Quencher lateral loads transmitted to basemat via the tie-downs using DFFR, Rev. 2 methods b) T-Quencher T-Quencher tie-down loads T-Quencher tie-down Identical to PaPL- 1978 not specified at this time. loads presented in Susquehanna

__, SSES DAR Section t,a 4.1.2.5 CB

%1 C7' 7 of 10 N

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LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION III. LOCA/SRV Submerged Structure Loads A. LOCA/SRV Jet Loads

1. LOCA/Ramshead SRV Calculated based on methods Accept NUREG-0487 Jet Loads described in NEDE-21730 subject to constraints and modifications identified in NUREG-0487 Appendix D Section III.A.1

2. SRV-Quencher Jet This load may be neglected Data from T-Quencher Identical to PaPL- 1978 Loads for those structures located test program pressure Susquehanna outside zone of influence transducer P5.5 shows no NRC accepted for four arm Quencher which water jet effect (SSES is a sphere circumscribed DAR Section 8). No signi-around Quencher arms. If ficant load beyond zone end caps have holes the of influence which extends sphere radius should be 5 ft. beyond Quencher arms increase 10 hole diameters.

To be confirmed in Long-Term Program.

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C7' 8 of 10 CO

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LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION B. LOCA/SRV Air Bubble Loads

1. LOCA Air Calculated based on methods A LOCA air bubble source Method is exten- 4/80 Bubble Loads described in NEDE-21471 at the vent exit will be sion of generic subject to following con- used as the source term modeling work straints and modifications: in a modified IWEGS/ MARS developed for Code (developed by Bechtel chugging analysis a) To account for bubble and GE for Chugging Load -Identical to asymmetry accelerations Definition) to establish PaPL-Susquehanna and velocities shall be velocity and acceleration increased 10%. flow fields. Application of flow fields will be same b) Use modified drag co- as generic positions (a) efficients or factor thru(f). A possible source of three times the that is being investigated standard drag co- is the NEDE-21471 method efficients. used to determine bubble formation with exception c) Equivalent uniform flow that tiine dependent drywell velocity and acceleration pressure history will be for any structure will be used to define bubble pres-taken as max. value sure.

"seen" by that structure not value at geometric center, d&e) Interference effects must be considered for structures separated

__. by less than three

( ,4 characteristic dimensions Cys of the larger structure.

sa To account for inter-ference effects use factor of four times the C7' acceleration and drag

'43 forces.

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LOAD OR PHENOMEN ACCEPTANCE CRITERIA LIMERICK POSITION UNIQUE PROGRAM DOCUMENTATION

1. LOCA Air f) Formula 2-23 of NEDE-21730 Bubble Loads shall be modified by re-(Continued) placing M by H

V where FB A V is obtained from Tables 2-1 & 2-2.

2. Ramshead Air N/A Bubble Load

3. Quencher Air Four-Arm Quencher load shall N/A Bubble Load be determined using source strength derived from bubble pressures calculated by methods in DFFR, Rev. 2.

T-Quencher load calculated T-Quencher Methodo- 1978 by Ramshead methodology and logy presented in bubble pressured described SSES Dar Section 4.1.3.

In DFFR, Rev. 2. Bubble shall be assumed located at center of Quencher and radius equal to radius of Quencher. The bubble pre-sure is assumed to be 25%

of calculated Ramshead bubble pressure.

C. Steam Condensation No generic load methodology condensation Oscillation Method is exten- 4/80 Drag Loads provided. Generic model & Chugging source at the sion of generic under development in Long- vent exit will be applied modeling work Term Program. in modified IWEGS/ MARS developed for Code to establish acceler- chugging analysis ation and velocity flow -Identical to fields will be made with PaPL Susquehanna

(/4 appropriate drag coef-C7' efficients. Source terms

'd are currently being defined from tasks A16 and A17.

W C=D 4-1J 10 of 10