ML20137W101

Forwards Yankee Atomic Electric Co Application of FIBWR2 Core Hydraulics Code to BWR Reload Analysis

ML20137W101
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	04/14/1997
From:	Duffy J VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20137W107	List: ML20137W101 ML20137W130
References
BVY-97-46, NUDOCS 9704180034
Download: ML20137W101 (2)

Text

w w.

r m

p rft ha [ 5 ' -

^

de

,1 s

1. m la VERMONT!YANKE'El x

{yNUCL,EARIPOWER CdRPORAilON'

~

~

.g

(

. Ferry Road, Brattleboro, VT oS301-7002

}

[

ENGINEERING OFFICE 580 MAIN STREET -

+

u*

BOLTON, MA 01740

'(506) 779-6711 April 14,.1997 -

BVY 97-46 i,

. United States Nuclesr Regulatory Commission JATTNi Document Control Desk i,

= Washington, DC: 20555 z l

1 References; (a)_ License No. DPR-28 (Docket No. 50-271)

. (b) YAEC.1299P, " Methods for the Analysis of Boiling Water Reactors Transient

'. Critical Power Ratio Analysis RETRAN - TCPYA01," Yankee Atomic Electric

. Company, March 30,1982..

' (c) EPRI NP-1923, FIBWR,"A Steady State Core Flow Distribution Code for.

Boiling Water Reactors, Code Verification and Qualification Report," Electric

- Power Research Institute, July 1981.

(d) EPRI NP-1580, RETRAN, "A Program for One-Dimensional Transient '

L Thermal Hydraulic Analysis of Complex Fluid Flow Systems," Electric Power -

Research Institute, December 1978.

p

Subject:

Submittal of YAEC-1339," Yankee Atomic Electric Company Application of FIBWR2 Core Hydraulics Code to BWR Reload Analysis"

~

Attached for NRC review is YAEC-1339, " Yankee Atomic Electric Company Application of FIBWR2 Core Hydraulics Code to BWR Reload Analysis."_ Vermont Yankee intends to use FIBWR2, a new version of FIBWR, to validate reload analyses which include new fuel types j

with part length fuel rods and varied water tube designs. The subject report describes the modifications to the transien.t Critical Power Ratio (CPR) methods [ Reference (b)], which determine the limiting fuel bundle or " hot channel" response to an Abnormal Operational

~

Transient (AOT). The most limiting AOT provides the largest transient CPR response from

-.which the plant's CPR operating limits are detsrmined. Since Vermont Yankee will use a fuel assembly with part length fuel rods in the next operating cycle, Cycle 20, it is our intention to

< applyLthis methodology in the Cycle 20 and subsequent reload analyses.

Current Transient CPR Methodoloov ;

!The present YAEC BWR reload mMhodology for determination of CPR operating limits is based 1

y on the FIBWR and RETRAN thermal h'ydraulics codes [ References (c) and (d)]. This.

- methodology empbys a.three_ step process for determining the plant response to an AOT. The i

initial step determines the steady. state thermal hydraulic parameters for the core design for

' input as initial conditions for RETRAN. The overall plant response to the initiating event of the

AOT is then simulated with RETRAN. The reactor core power and thermal hydraulic response -

of the system model are then applied as boundary conditions to the hot channel RETRAN g

i i model.1 The hot channel response determines the transient CPR via a post processor, TCPYA01, which contains the vendor critical power correlation.

il 9704190034 970414 N

MN PDR. ADOCK'05000271 @

?i s

i P:

PDR,Q.

1 km, w.. uc,

~

m

.a

^

.i

• 1 I

VERMONT YANKEE NUCLEAR POWER CORPORATION f'

United States Nudear Regulatory Commission -

' April 14,1997.

Page 2 of 2 l l

j Use of FIBWR2 for CPR Determination

' The FIBWR2 code " hot channel" methodology has been qualified to replace the L RETRAN/TCPYA01 method. The qualification, documented in the attached report, has been.

implemented by:

• ! comparison to analytic derivations of a flow decay and sinusoidal flow oscillation transients.

benchmarks to the General Electric ATLAS test facility critical heat flux experiments.

e 1 comparison to the approved YAEC CPR methodology u' sing RETRAN.

e Based on the results of this qualification effort, FIBWR2 is an equivalent replacement for the

.RETRAN/TCPYA01 method.'

.j Steady-State Anolication of FIBWR2.

i

Vermont Yankee will also use FIBWR2 as the replacement for FIBWR, the existing computer i

code for the BWR steady-state reload methodology and the foundation of FIBWR2. Vermont 1 Yankee found that FIBWR2 performs identically to the FIBWR code for calculation of steady-state thermal hydraulics. The steady-state qualification of FIBWR2 has been included by

' reference in the attached report.

1 Reauested Review Schedule Completion of your review is requested by November 30,1997. This will allow time to.

incorporate a reference to the NRC's evaluation of FIBWR2 into the Vermont Yankee Technical Specifications so that FIBWR2 can be used for validating Vermont Yankee's Cycle 20 reload l

analysis being performed by General Electric. Vermont Yankee will submit an administrative l

Technical Specification proposed change by May 30,1997 to incorporate this reference. This l

will allow a parallel review of this submittal and the subsequent Technical Specification l

proposed change, in this way reference to the NRC's safety evaluation can be promptly added l

1 to the Vermont Yankee Technical Specifications once the NRC's evaluation is complete.

We trust that this submittal provides sufficient information for your review. However, if additional information is required,' please contact this office.

1 Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION -

$fMA

.i 4

L James J. Duffy Licensing Engineer l

c:. USNRC Region 1 Administrator.

lUSNRC Resident inspector ~-VYNPS F

USNRC. Project Manager-VYNPS i

.l l

n w.

=

YANKEE ATOMIC ELECTRIC COMPANY

[

k e

c F

YAvues

~

i c

[

r

]m