ML20195J044

Refers to Discussions with Licensee on Future Suppl to Application on Replacement Steam Generator Reactor Coolant Flow Differences

ML20195J044
Person / Time
Site:	South Texas
Issue date:	06/14/1999
From:	Alexion T NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
TAC-MA1911, TAC-MA1912, NUDOCS 9906180068
Download: ML20195J044 (6)

Text

,._.. .- _ _ _ _ _ - _

b n 1

June 14, 1999 MEMORANDUM TO: File FROM: Thomas W. Alexion, Project Manager, Section 1 ORIG. SIGNED BY Project Directorate IV & Decommissioning Division of Licensing Project Management

SUBJECT:

DISCUSSIONS WITH LICENSEE ON ITS FUTURE SUPPLEMENT TO APPLICATION ON REPLACEMENT STEAM GENERATOR REACTOR COOLANT FLOW DIFFERENCES (TAC NOS. MA1911 AND MA1912)

The U. S. Nuclear Regulatory Commission (NRC) staff has had discussions with the licensee on its May 7,1999, application, as supplemented by letter dated May 20,1999, for a license amendment to reflect replacement steam generator reactor coolant flow differences. The licensee is planning another supplement to the application and has requested further discussions with the NRC staff.

In order to facilitate future discussions between the licensee and the staff, the licensee provided the information in the attachment. The licensee has informed me that this information is preliminary and it plans to follow-up this information with a formal submittal. The purpose of this memorandum is to place the attachment in the Public Document Room Docket Nos. 50-498 and 50-499

Attachment:

As stated h

DISTRIBUTION:

rDochet Slesj60-408 and.50-499)

PUBLIC PD4-1 r/f /.O To receive a copy of inis document, indicate "C" in the box OFFICE PDIV-1/P3 ; C PDIV-D/LA C NAME TAlehh CJamerson h DATE h /h h99 (s / lY /99 b DOCUMENT NAME: G:\PDIV-1\SouthTexas\MEMA1911.WPD OFFICIAL RECORD COPY l

h61so0689hd6f4 p

e DOCK 03000498 PDR -

z.

. ___- ~

. s o nra

+

3e UNITED STATES

!* j 2

NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205W0001

\...../ June 14, 1999 MEMORANDUM TO: File FROM: Thomas W. Alexion, Project Manager, Section 1 Project Directorate IV & Decommissioning Division of Licensing Project Management

SUBJECT:

DISCUSSIONS WITH LICENSEE ON ITS FUTURE SUPPLEMENT TO APPLICATION ON REPLACEMENT STEAM GENERATOR REACTOR COOLANT FLOW DIFFERENCES (TAC NOS. MA1911 AND MA1912)

The U. S. Nuclear Regulatory Commission (NRC) staff has had discussions with the licensee on its May 7,1999, application, as supplemented by letter dated May 20,1999, for a license amendment to reflect replacement steam generator reactor coolant flow differences. The licensee is planning another supplement to the application and has requested further discussions with the NRC staff.

In order to facilitate future discussions between the licensee and the staff, the licensee provided the information in the attachment. The licensee has informed me that this information is preliminary and it plans to follow-up this information with a formal submittal. The purpose of this memorandum is to place the attachment in the Public Document Room.

Docket Nos. 50-498 and 50-499

Attachment:

As stated 1

l l

l

AN-80-1999 M:24J tG MTl@Df Utds9 4 RE M t4 7<&J South Texas Project STP Elecinc Genercung Station Nuclear Operating Company Box 289 N5014 Wadsworth, TX 77483 Date: June 10,1999 Number of pages including mwr sheet: 4 4 I

To: Toen Alexion, NRC/NRR From: Mark Van Noy, Nuclear Licensing South Texas Project Nuclear Operattar C-eny 1

CC:

REMARKS: O ursent O Foryourreview 0 ReplyASAP O Pleasemmment FOR: TOM ALEXION Note that in Table I the mathematical signs for the first and fifth values have been changed to neg This is because Westinghouse uses another step for creating the inputs to RETRAN that inverts th for these functions, thus, it is not necessary for them to do this manually. In the original submittal, these values were provided in their raw data format instead of a form appropriate for direct entry into RETRAN.

The values are now appropriate for direct entry into the RETRAN deck.

Please review and give us Mr. Jensen's comments. We will then submit on the docket.

ATTACHMENT

, , , ,,.f ...,,--.w%.=v-e .w. espe , ygPe4 N ed"" " " ' ' ~

• aW%FRWs iWPa NtKUSLi LICENSING P. 0244 DRAFI' OF EXPANDED RESPONSE IOR RCS FLOW RAI OUESTION 4.b Pm t ets Figure I shows two sets of core thermal limit lines in terms of core inlet temperature as a funcl the South Texas Project (STP). The limit lines identified as " Actual" were developed based o shape, using the methodology described in WCAP-11397-P-A (" Revised 1hermal Design Proced used to generate Technical Specification Figure 2.1-2 and to revise Updated Final Safety Analys (UFSAR) Figure 15.0-1. These " Actual" limit lines are part of the reactor core safety limits which, a the response to question 2 of this request for additional information (RAI), were shown to be pr existing OPAT and OTAT setpoint equations. Note that the limit lines of Figure 1 are present ranging from 80% of nominal up to 120% of nominal, although departure from nucleate boiling (DN limiting condition throughout this range. Depending on the pressure, there is a power leve saturation bcevus the limiting condition, and at some point, the main steam safety valves will actui additional primary-side heatup. The OTAT reactor protection function is designed to prevent the occurren saturated conditions within the hot legs, and to preclude DNB conditions within the core for power levels not protected by the OPAT trip. The OPAT reactor protection function prevents operation above 118% of rated thermal power (RTP).

l The " Adjusted" core thermal limits of Figure I were developed from the " Actual" limits and account for v in the core axial power shape. Durmg the development of the OTAT setpoint equation for South Tens,

{ for the K1 gam (see WCAP-8745-P-A) was reduced to allow widening the fadeadband. The deadband wa widened to permit normal plant operation without operating in the fm penalty region. The DNB core thermal limits were reduced to address the effects of the wider range of power shapes that can occu dead-band. These reduced limits still represent the limiting DNBR of 1.38. The partial derivatives used i RETRAN DNB ratio (DNBR) model are based on the " Adjusted" core limits and it has been verified that the OTAT setpoint equation protects these " Adjusted" core limits.

Figure 2 shows a comparison of the " Adjusted" core limits presented in Figure 1 and the condition to the DNBR limit (1.38) as predicted by the RETRAN DNBR model. This model used the partial derivative coefficients presented in Table 1. Note that the plots of Figure 2 are presented in terms of reactor c TAvo as a function of core power rather than core inlet temperature as a function of core power. The RETR DNBR model is applicable at or above full power conditions for all pressures between the low pressur reactor trip setpoint (1845 psia) and the high pressurizer pressure reactor trip setpoint (2435 psla) assumed in safety analysis. This comparison shows that the RETRAN DNBR model closely predicts the limiting DNBR pressures equal to or greater than the nominal (2250 psia) pressure. At pressures below nominal pressure, the RETRAN DNBR model conservatively predicts the limiting DNBR to occur at temperatures that are less than core limit values. With this, it is concluded that the partial derivative coefficients used in the RETRAN DNBR model are conservative for DNBR evaluations of applicable transients postulated for STP.

Table 1 RETRAN DNBR Calculation Inputs Q 703849 1 Word 5 (CGAIN) j - 0.0524 l l 703851 f Word 5 (CGAIN) 1 0.005631 l l 703852 ,,,,

Word 6 (CPI) l ,,,,,,_,,,, 0.074 28 l l 703853 ,_l Word 5 (CGAIN) 122.0 l l 703854,, Word 6 (cpl,)

.,, l - 619.27 l l 703858 Word 5 (CGAIN) l -0.027674 l

{ _703897 ,,,,,,,,,

Word 6 (CP1)_ l 1.38

,,,,,_, l

~'

JUN-10-1999 86224 NUCLEAR LICENSING P.03/04 DRAFT OF RYPANDED RREPONSE FOR RCS PLOW RAI OUESTION 4.b raptors Figure 1 Senftfl Testat DM Umit Liftte (Actuel tre. Adjutted) e4o

. . 3450pela

.30'

....-gg

- .. .- q s , q,q. -

.,.. s -

s k.

..-- es, -

s

==-

N, 's g:gls s =-

..smp [N, N,

• g N*

N N

's s.h, a

3 .- s -

s.

s,g:s 570 -

g \g g N- N* A

-aw g \

s geo . " WW \  %,

m. \*

y sao

... .. u .. .. a i

u

~ ..  ;

l 1

l l

1 i

i i

e.g'.?

ew$

• 9 u* gmM hm m- ?c3 2 f

' a 2 _

1

, =

Nd '

s e

A e

• s e

mtu

j s

t d e

m e R A *

- , 5  %

t a

" 1 r

, - 1 ua s

" - 0

• 18

' to

' h

, b

, = B N

1 D

) m  % m 1 o k

h. N ,

s e .

4 A = ?g:  : I:t :'

r e as S. ta N R n c O T '

, a a t

E n o ev s

I T

S R

, . 5 eV f

a _

E s - . 0 n

o t y U v  ;*

1

) g af c e l

O d ' 4: :I I :t :' l a n S a n

I t e n e immm A s - - mA te n a a R j u - otoS o f 2 d - N h _

W O ru e

(

A - f e oNw e M00% _

j j i b. n 1

L g F H i t

s j.1 .! * !I - !! 1 oowh na t e ch hr il S m - c b, N e C a wt a _

mwe i i Iji- r

.I* .

R L .:.!I*!1*!' F

( o rg R e r rer:.- le b r o

O o ' g*{ j ,.i. we wc n

o G a m F C -

i:;:I : i:I :' oo l E s - . 5 Pp a u r q S a 9 wf r e x . - 0 s e s N e .

. y wl nn po ev e f

O T -

P h

- - de e i h e l

r S - s ty ow E t u - - n o

t f

n e tp R o -

a a D S - - _

ids lb e .

E *

• 9 _ e ac _

D ia a i 'a

• a

• 0 _ hu p s ps o is a .

t N is p .

p

-.e i

s . a A 0 0 0 o p P 5 0 5 0 ra 4 4 0 0 X 2 2 2 2 0 8 3

m, . sne t E = = =

2 1 s ic F P P P

=

=

i o i f

O P P p ef e 5 0 5 d, o T 8 a lce F 0 2 te d 2

d p o A na, 0 5 m R

o 24 BR D o c d N

a. a nD o

s 0 N s

i 04 A R 2 T 5 B. o = E 5 M 5 5 5 O Pr P R 6 6 1

9 t 5 r e 6 5 7 5

5 5 Fo Fo

• Th

(;>*> "

- 4P D

? cb

.