ML20090M532

Provides Supplemental Info to 740123 Rept, Permanent Plant Changes to Accommodate Equilibrium Core Scram Reactivity Insertion Characteristics

ML20090M532
Person / Time
Site:	Monticello
Issue date:	04/10/1974
From:	Mayer L NORTHERN STATES POWER CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9105060219
Download: ML20090M532 (6)

Text

AEC DI tItD~ ION TOR PART 50 DOCVET Pr AL (TDiPORAftY FO!04)

CONTROL NOi, 3254 FILE:

FROM:

DATE OF DOC DATE REC'D LTR MEMO RPT OTlER Northern States Power Co.

Minneapolis, Minnesota L. O. Mwcr 4-10-74 4-15-74 X

TO:

ORIG CC OTlGR SENT AEC PDR XXX SENT LOCAL PDR XXX J. F. O' Leary 1 signed 39 CLASS UNCLASS PROP IhTO INPUT l10 CY S REC' D DOCITT NO:

XXXX 40 50-263 DESCRIPTION:

ENCLOSURES:

Ltr furn suppl info re rpt 1-23-74 entitled,

' Permanent: Plant Changes to Accommodate Equilibrium Core Scram Reactivity Insertion D.O.NOT EEM0YE_

Characteristics i

ACKNOWLEDGED PLANT NAME: MONTICELLO FOR ACTION /INFORMATION 4-16-Y4 GMC BUTLER (L)

SCIMENCER(L)

!ZIDiANN(L)

REGAN(E)

W/ Copies W/ Copies W/9 Copies W/ Copies CLARK (L)

STOLZ(L)

DICKER (E)

W/ Copics W/ Copies W/ Copies W/ Copies PA'.ti;(L)

VASSALLO(L)

KNIGHICN(E)

W/

Cvph.

W!

,vplum W/ Cuple.

W/ Copies KNIEL(L)

PURPLE (L)

YOUNGBLOOD(E)

W/ Copies W/ Copics W/ Copies W/ Copics INTERNAL DISTRIBUTION r enG THI' TEC11 REVIEW DENTON A/T IND

/ AEC PDR HENDRIE GRIMES LIC ASST BRAI7 MAN YOGC,ROOMP-506A

/DIGGS(L)

ScitROEDER GA1241LL SAL'12 MAN B. WRT MUNI21NG/ STAFF MACCARY KASTNER GEARIN (L)

CASE KNIGHT BALLARD COULBOURNE (L)

PLANS GIAMBUSSO PAWLICKI SPAUGLER LEE (L)

MCDONALD t 00RE (L)(BWR)

TELLO ENVIRO EED

)

DEYOUNG(L)(WR)

HOUSTON MULLER SERVICE (L)

INFO C. MILES SKOVHOLT (L)

NOVAK DICKER SHEPPARD (L)

/GOLLER(L)

ROSS KNIGHTON SLATEPs (E)

B. KING (E/W-358)

EEMR P. COLLINS IPIOLITO YOUNGBLOOD SMITil (L)

EISENL'UT DENISE TEDESCO REGAN TEETS (L)

REC OPR LONG PROJECT LDR WADE (E)

PILE & REGION (3)

LAINAS WILLIAMS (E)

MORRIS BENAROYA 11ARLESS WILSON (L)

STFFLE VOLI}iER 9105060219 740410 ZXTERNAL DISTRIBUTION PDR ADOCK 05000263

/1 - LOCAL PDR MINNEAPOLIS MINN_

P PDR

/1 - TIC (ABER$1 THY)

(1)(2X10)-IIATIONAL LAU'S 1-PDR-SAN /LA/NY

/1 - NSIC(BUCllANAN) 1-ASLEP(E/W Bldg,Rm 529) 1-GERALD LELLOUCHE 1 - ASLB 1-W. PENNINGTON, Rm E-201 GT BROOKHAVEN liAT. LAB 1 - P. R. DAVIS (AEROJET NUCLEAR) 1-CONSULTANT' S 1-AGMED(Ruth Cussenn)

/16 - CYS ACRS "^! S2 NEk't! ARK / BLUME/AGBIBI AN IM-B-12 7. GT.

l Sent to Lic Asst Diggs 4-16-74 1-GERALD ULRIKSON...ORUL 1-RD..l!ULLER..F-309 q 1-B & M SWINEBROAD, Rm E-201 GT gg gg,

o e

e NSED NORTHERN STATES POWER COMPANY M I N N E A Pol.l S. M I N N E S OT A 95406

{,-

April 10, 1974 N

N 9

p i

Mr. J F O' Leary 6[ APR b

^

b

1. .C

, h ' '// p,~8

@k I

Directorate of Licensing 2

tip tflMg

/

['un [cttti Office of Regulation j

C h*p 5f U S Atomic Energy Commission

\\

Washington, DC 20545 As A4

/.

\\\\

4, t/f>/.71110\\ /

/

'tr

.s'

Dear Mr. O' Leary:

t

}DNTICELIh NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Supplemental Information to January 23, 1974 Report Entitled,

" Permanent Plant Changes to Accommodate Equilibrium Core Scram Reactivity Insertion Characteristics" On January 23, 1974, we submitted the aMve referenced report ditch praposed the following changes:

1) Removal of the spring-loaded safety valves and the addition of safety / relief valves with discharge lines piped to the suppression chamber.

2)

Insta11rtion of the prompt relief trip (PRT) system designed to open relief valves in anticipation of certain reactor vessel pressurization transients.

3) Adoption of riodified scram insertion tinies.

4) Acceptance of more appropriate conservatism factors to be used in analytical calculations.

A March 14, 1974 letter from Mr. D J Skovholt indicated that completion of the review of analytical methods and the PRT concept was scheduled to be completed in approximately six months.

The letter proceeds to ask that we provide an alternate interim analysis to allow Cycle-3 operation concurrent with your review without dependance on the PRT system or a reduction in conservatism factors. The M1owing calculations show limitations within which cycle-3 operation can proceed within these constraints.

The March 14, 1974 letter states that we may proceed with the plant modifications as planned and in the manner described in our January 23, 1974 submittal. Work is presently underway removing the four safety valves and installing the two required safety / relief valves plus at least one installed spare safety / relief valves. Portions of the PRT system on which there are no unresolved Staff concerns are also being installed during the current outage.

REGULATORY DOCKET FILE COPY 3E54

NOR. HERN OTATEO POWER CCen4PANY Mr. J F O' leary Page 2 April 10, 1974 l

Analyses of abnormal operational transients have shown that the turbine trip with failure to bypass is the most limiting transient.

The results of that transient have been analyzed for both the Generic B and the EOC-3 scram reactivity curves.

Table 1 shows the assumptions used in the analysis.

The analyses were done assuming six safety / relief valves, a direct scram on turbine stop valve closure, proper tripping of the reactor recirculation pumps, design conservatism factors and no PRT system. Since the heat flux -as close to limit conditions for a turbine trip without bypass at the end 2f Cycle-3, the transient was calculated for reduced power levels. The results of the analyses are as follows:

Parameter Generic "B" EOC3 Power Level (%)

100 90 95 100 Peak Steam 11ne Pressure (psig) 1167 1168 1190 1213 Peak Vessel Pressure (psig) 1192 1193 1214 1237-Peah Avg. Surface '.iest Flux (%)

105.5 105.1 113.0 120.4 HCHFR 1.68 1.60 1.31 1.08 An overpreseure analysis to show compliance to the ASME Code was summarized in 1

the January 23, 1974 submittal. The analysis was based on six safety / relief valves, no safety valves, design conservatism factors and no PRT system.

That analysis therefore, meets the conditions requested by the March 14, 1974 AEC staff letter. The results of that analysis show that for the MSIV closure event j

from rated power and with failure of direct scram with the Generic D scram

^

reactivity curve, a peak pressure of 1285 psig occurs at the bottom of the vessel.

This pressure is well below the vessel overpressure limit of 1375 psig.

1 The analyses show that rated power can be maintained ur.til the B scram reactivity curve is exceeded.

This occurs at 4200 MJD/T at which time the control rod i

pattern must remain fixed until reactor power ramps down to 95% of rated as discussed in our August 21, 1973 letter.

The 95% power restriction is required j

for the remaining 750 NWD/T of Cycle-3, without further analysis,because the heat flux reaches a threshold above which the minimum critical power ratio a

may become limiting.

Technical Specification changes were requested on March 1,1974 to accommodate l

the changes discussed in our January 23, 1974 submittal.

Since the later submittal has not been reviewed and approved to date, not all of those Technical Specification changes requested are appropriate at this time.

However, because some plant changes have been authorized and impicmented, certain of the requested changes are required at this time.

Proposed changes i

4, 5, 16, 18, 19a and 24 should be made directly and items 3, 6, 7, 8. 17, i

19b, 20a and 20b can be issued with appropriate alternate wordf og me le necessary by this interim situation.

(Note that items 19 and 20 were re.ateu in the Fkrch 1, 1974 submittal and are identified as 19a, 19b, 20a anu 2Cs abeio.,

NOR. r4ERN OTATEO POWER Co..iPANY 1

I f

Mr. J F O' Leary l

Page 3 April 10, 1974 a

i The Menticello reactor is presently scheduled to resume power operation on May 5, 1974. We request that the above changes be incorporated in a timely

]

na ner to allow the return to power operation without delay.

In addition, our Technical Specification change request dealing with the insertion of j

8x8 fuel dated February 27, 1974 and the change request involving fuel j

densification considerations dated February 28, 1974 are requested on the j

same schedule. We further request that you give continued priority to the j

evaluation of analytical methods and the PRT system such that through a 3

j timely review of either or both of these items, we might avert an unnecessary

}

power reduction at the end of Cycle-3.

i j

Yours very truly, 0

-Qg

}

l L 0 Mayer, PE 1

Directo-of Nuclear Support Services 4

IDMhnw/1h i

cc: J G Keppler j

G Charnoff j

Minnesota Pollution Control Agency Attn. E A Pryzina l

{

attachments e

a l

4 I

i 5

)

i i

d l

..,.,....g y,.,

,.,n.,,,---,

ngm v

l 1

TABLI I, Inputs Used for Transient Analyses Generic "B" EOC3 Power Level (%)

100 90-100 l

Core Flow (%)

100 100 Steam Flow (1) 100 90-100 Dome Pressure (psig) 1025 1013-1025 f

Relief Valve (RV) 6 6

RV Setpoint (psig) 1080+1%

1080+1%

Safety Valves (SV) 0 0

4 Scram Curve (See Figure 1)

Generic "B" EOC3 Scram Fbitiplier 0.8 0.8 Scram Rod Dri'te 67B 67B Void Coefficient (@ 100% Power-c/% rat ?d voids)

Calculated

-6.57

-6.57 i

Analysis

-8.22

-8.22 i

Doppler Coefficient (@ 100% Power-c/ F) f Calculated

.205

.205

}

Analysis

.185

.185

n.

~.. -.. ~ -

1.0

. +

64.

._ f.

j DU

..gs esa

.i..

.4 ra

. ~ _.

g.i.

.j.,

4:a pp

. 2 4 _.

-~

.g.

.t,1.4 6

i 3; r i.,

g,.

_.1

-e

.1.,

.4, m.

..a.

4_

,4

.: 6

..j.._

r

...,4._.

t _ _. I __... -. -

.~-.4..

.,..,4.,

_ __ l. _.

, t., - m-.

t.,- t _-.-.8-E. _

A 1'-

d.

L 4

.a '-

.-F+-,-

. - - -. - -.r_

r-u. ~ t--_.

--i-___-_,.__

- ^-

...u.

f_--

9

_-. 71 T1.4 -._'

_ _ l _ _ f._;

j __. _ _ _ _

,__af.-_4}_.

5 m.

1. _;

i!

22,

.; a,

,t 1

.-_ m u_.4, 1T'T._.u

_f a_

,+ +

,a.

, g

....a

.__ +

_m &

4-j

=

.-_++,.

.,+

.y a

^

p.

.,44 m, _ t h..

y 4..

.. +l.o.1.,M'._,.y m,

9441

.8 4-.-.

.4

.p

.i 40 g

u.

y,,,.,-

2 a

_g p__ _

g.g2..

2

.7

{

x,.

.t.

4

.;,1,

4.pa. g

_., t

+

a a-u

"-it

ij 3-e -.

->4 A 64.4

+b 4}i,'.p 7

i

w-

.;.i

,r, TA+,+ g

g 4

-H i

.1

, Jit

.-i, ii: ttn 1,,

u_

4___

i a___J 3

4 5

1 -

+

4+m,e, u.,

gc

i;-

4.A,,._, L.a., _ 4.%.-

1

,4

_+a~

g_ m _-

,1

_ uaa._. u-i.

.i.

i u; - -

/.,

.~

a+ e,

. 3i1 i_

1 r

6

.4.,

-. __.. _._I, ~f.__f._ '..

.x,,.

yya

.u.r:

~

~ u. i..L E _ __

'i. *"+,+ ' ",_.t s

r

_._ t __ _.

~30

.a.

as r

1

+, m, - a y u,.. u i, I -

_1.___

_4 c5, y-y 2 y

c 1

.. ~., _...-

i I'..4u.

4 424:

-i,.

,,,4 4 4,

4

.f.

le> >

.,4

..a#

g

- i. q.s uu 32

. _.24_.~

o p. _p 7u....4._

t 6

..+-

s

.a u.

r u.

,., y_

.-,. H _:.+-.

. 44 rh;...

3 1

IiI a

M i i 1

i

.. tw H4

,m-,.

1. 4, ". c -*. -

i :

r.

g

.5 S g..,tt..-1.~.

..W, i 2._4.

_a m

8

_.__ L ;

. m.

e,-.

+..

-a.-

1,. _. Calculated Generic,,B" Curve a__ _ =

___.,__{_.2 m,~.h.

y,_, g-

., c m+

.._i__

+

+.

o_7

~ _ _

w

-w.

S 4... 71 ~-

4l.m. g, w

a

..m_ _2 Analysis Generic.B. Curve m

,. L..

g:,.

c) g.

.. j.

1 _r.

v

_1

.g

_a s

..a o

_..t Calculated E0C3 Curve 20 r

p. p, f. _ p_m_ _

y,_4,.

y

_t:f.. $. _p.. _I,, t,T.1 q.

y

4.. g 4, Analysis E0C3 Curve g

r

~-tu:

u.. -.,u, Iy, u

+..

.a.

r.

n._p y,,..,..

g

,_ r.

2 4,

v

-+..,..j wa.

g M_

__4

-7

_~

_..-i_..

.. - j. _

. V -==

.../...

_,a t..}

,.a_,-

6-pr _.

... ~,

• .J

_1a

.44.l.

,6e 46.

4 f,_.

%[e_.$ 4

+-.1. 4a.

.a gL.-

.II.~.. 4-.

_A -4 4 44 a

,_...m

.a. _a

-, p

,_t_*-

- /

- ^ - * -

A

7.,.a _

44s.

'4 t.-&. --_

' aa

... - _=A

.f.___

,A p

~ ~ ~

' ~ ~ '

' ' - ~ '

' ~

+

- ~ ~ ~ ',j"_~~~~,.~m

.--t

, I n.

.laa p. __

. ~ _..:..

e

'- - - ~ ' _ '

.,4 4.

..,i

-~ ~ - - '

~ ~ ~.. ~ ~ _ ~ _,

_ - _ ~ ~ _

._ g ~_.

10

• 2

-...F..

1 -' --*--

I. - _1

-- L ***-

a, A

4_____

_.... 4

.. 6 t

.16 t '3.A

.- 4.e

~~.--

-i-

,_Q:.... /-

w

.__L____..

_7

.,.14,

.y -

+_

..__p__._.

u.

.a T,,_

t i

... u.

.,.4 4. /

5' e,.1

!L

_y.

.-.h,.-

L.-_-

.A--_.4-

. + - - _.

_. _ i._ __.

j--

4 g

__.-..,4 w pa_-.

A+-.-

-._,A.-

p-4 o

a --

i p

r.4 4.__-

p..

A

... s f_.

4-

~_

.y

..f _,+

4.4.

..u-L..

.a 1

L_.

r,.,+_

m.

_. g gg i!,

' FIGURE 1.

MONTICELLO SCRAM REACTIVITY CURVES j[_._.

. s__ _ :1 p / /r.

_. s_..

tr

-f

,,s e

.r,.

.T -.

dir.-.-._ _Tr"-;-F"- r' '-*

+4. a I

__,3. y i:.

t ; *-

2.

. _ _.._ g.

'.a.

-H_

=e. -. p._.,44 :

l+--,,-

--.-4-e

i l

4 1

2 3

4 5

6 TIME (SECONDS)

Figure 1.

Scram Reactivity Curves used for Transient Analyses