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UNITED STATES NUCLEAR REGULATORY COMMISSION W ASHINGToN. D. C. 20555 NOV 1 0 $75 Doeket No. 50-219 LICENSEE: JERSEY CENTRAL POWER 6 LIGirr COMPANY FACILITY: OYSTER CREEK NUCLEAR GENERATING STATION i
SUl4RRY OF MEETING HELD ON OCTOBER 15, 1975 TO DISCUSS EXXON. NUCLEAR COMPANY'S ECCS EVALUATION MODEL FOR NON-JET PUMP BOILING WATER REACTORS On October 15, 1975, a meeting was held in Bethesda, Maryland with representatives of General Public Utilities Service Corporation, (GPUSC) and Exxon Nuclear Company (ENC). The purpose of the meeting, which was requested by GPUSC, was to discuss ENC's proposed integrated-emergency. core cooling system evaluation model for boiling water reactor non-jet pump plants. A list of attendees is enclosed.
BACKGROUND The evaluation model used by Jersey Central Power an~d Light Company (JCPGL) to evaluate emergency core cooling system (ECCS) performance for the Oyster Creek Nuclear Generating Station-is a composite of (1) the General Electric (GE) ECCS evaluation model for GE fuel, and (2) a. combination of the GE ECCS model and the ENC non-jet pump plant-BWR-fuel heatup model for the Exxon fuel. The current JCP6L cvaluation model, although conservative, does not include an approved analytical technique for calculating extended nucleate boiling for postulated small breaks;-hence, the large break model with characteristic short duration post-break heat transfer is used for all break sizes.
The calculations using the current model are conservative; however, this conservatism results in a power penalty of about 15%.
The proposed
- ENC integrated evaluation model for BWR non-jet pump plants includes consideration of flow coastdown and extended nucleate boiling after j
a small break. GPUSC stated that the model will be applicable to the Oyster Creek plant.
In addition.to the power penalty resulting from use of a conservative ECCS evaluation model, the current minimum critical power ratio (MCPR)
- also limits reactor power to about 85% of rated power. To relieve both limiting conditions, JCP6L plans to (1) submit new ECCS calculations based on the ENC-integrated model, when approved by the NRC, and (2) propose new MCPR limits referencing a topical report on the XN )
critical power correlation to be submitted by ENC.
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The purpose of this meeting was to discuss proposed ECCS evaluation
,model.
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SUMMARY
_The. ENC non-Jet pump BWR ECCS evaluation model is-based on the-ENC implementation of the RELAP 4' computer program and the ENC heatup.
model. -It was. stated that ENC has minimized the number of items that i
have'been changed'in their fuel heatup model.
G. Sofer, ENC, ' stated that the RELAP 4 calculations give. fluid velocities that can be used to calculate heat transfer based on data available'in the open literature.
- L. Steves summarized a comparison of selected features in the RELAP 4 analytical model for PWR's and non-jet pump BWR's.as.follows:
-Feature PWR
'Non-jet Pump BWR
. Core Crossflow
' Considered N/A Lower plenum 3 Homogeneous-Volumes 1 volume, phase separation'
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-Downcomer
. Homogeneous Phase separation Steam Separators N/A Phase separation volume
.0ther topics were, discussed including sensitivity of nodalization.
GPUSC also stated that they would justify use.of a 1.0 multiplier instead of._a 0.9 multiplier' on the spray cooling heat transfer coefficients currently used for the 8x8 fuel assemblies. GPUSC stated that the justification would be based on Exxon'.s spray cooling test results.
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JCPGL has proposed modifications to the Oyster Creek ECCS based on'a single failure analysis. An evaluation of ECCS performance for the modified system will be required using the current'JCPSL ECCS evaluation model.
We stated that it is our position'that the 0.9 multiplier should l
be applied to the' core spray heat transfer coefficients for the 8x8 1
fuel assemblies in this forthcoming evaluation. GPUSC stated, subsequent j
to the meeting, that they will use the 0.9 multiplier for this evaluation.
In conclusion, GPUSC representatives stated that they need revisions to
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both-the ECCS and MCPR limits in order to gain significant power level, i
GPUSC further stated that they will shut down in the near future to retube their condensers and that they would like to have the MCPR and
.ECCS related limits revised by mid-January 1976.
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Ne stated that we plan to do a mini-review of the proposed Exxon integrated i
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model.
Based on the mini review, we would identify any major staff concerns regarding the model and provide an estimate of the time needed to complete a ; full review of the proposed model..
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' Walter A. Paulson j
Operating Reactors Branch #3 Division of Reactor Licensing 1
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s ENCLOSURE.
P ATTENDANCE LIST MEETING ON OCTOBER 15,-1975 4
EXXON NUCLEAR' f
G. Sofer 4
G. Owsley W. Nechodon T. Krysinski L. II. Steves I
~. A. Bjornard' T
GENERAL PUBLIC UTILITIES SERVICE CORPORATION j'
R. B. Lee K.'A. Greene
.T.
M.' Crimmins, Jr.
-N. G. Trikouros i
G. R. Bond
'PICKARD'LOWE 6 ASSOCIATES T. Robbins NRC'- STAFF W. Paulson R. Woods
- 11. Vander Molen N. Lauben I
F. Orr f
P. Norian i
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