ML20125D691

Safety Evaluation Supporting Change 13 to License DPR-11, Authorizing Deletion of Separate Requirements on Max Boiler Power Fraction & Min Recirculation Flow for Given Total Reactor Power

ML20125D691
Person / Time
Site:	05000130
Issue date:	05/26/1967
From:	Skovholt D US ATOMIC ENERGY COMMISSION (AEC)
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References
FOIA-85-54 NUDOCS 8506120441
Download: ML20125D691 (3)

Text

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sArm EVAURTION BY 'DE DMSION OF RFACML 1.ICDEDG  !

IN 'DE_MAM3t OF  ;

NORD53W STATES POWDt CQMPNW ,

PA3HTDEKR A10 HIC POWDL PLANT D00CT NQil0-130

> PROPOSED QiNgE NO 13

, i EDEMEE - t i By Asundment No. 41 dated March 17, 1967, Northam States Power Ocupany m- I  !

quested a change in the Technical Spoolfications of Liesnee Ilrn-11. The l change would authories deletion of the separute equimeents on maximse '

boiler power faction and minisman.mciruulation flow for a given total remotor L power, and would incoryerute a requimeent for a minisase alicumble hummut ,

j ratio. We have designated this request as Proposed Change No.13. -

DIEWBRIQ8 .

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'1he inent, instians wars intended to protect the bollar meetian of ,

the inder by a limit on the fruction of total that I  ;

een be generuted in the be emotion and specifying a minimam isn flow for a given total power. 'these limite unzu selected on the basis of l design omiculations befoss the reactor was opasuted. Oposuting emperianne ,

with the remotor during startup, and initial operation ln the power range has i shown that spesuting pamesters an different frem design ampostations.

Evalustian of operut conditiene on the beeis of experimental results shoue that although full two ion flow is less than design exportations, the actual bum out ratio (30R) the specified oortulation is greater than

• empeated. The control red posit noosemary in operution results in a sure favorable power distribution. Radial peaking is reduoed, the minissan i nom ooours in the lower part of the core desu average heat flum is louer due l to larger fuel red dianatore, and at a point uhere steam quality is louer. .

The proposed spoeifications would change a soma condition fama a limit on the 1

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retiese power /rucirculation flow, to a limit on the ration boiler power / I suoiseulation flow. The latter safety limit is more meaningful to reester safety in this rusetor. '!he safety system est point would be selected to insure i that the boiler umuld never be apesuted in such a manner as to violate the- l minisaan specified bum out ratio. '!he licenses has agreed that the specifiestian  !

would be applied by establishing a limiting power-flow ourve for 1.5 30R, based on actual power and including factore for changes in power distribution, and the ,

instrsament settings would be adjusted to ocupeneste for variations between in-dianted and actual power that aries frem the control rod and reaisuulation flaw I

pungrume utillmad. '!he change would also remove the operuting limit on boiler power fraction, but does not affect the operuting limite on titeady state bum out rutto (1.9) or transient bu m out rutio (1.5).

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. l 6e .' 7 The gv g: d specification is added under section 6.1.l(b) so that the function may M ':ypassed during flooded mode startup whom channels 5 and 6 limit power to 4%, Which is below the useful range of the power to flow protection. Since boiler protection would be fumished by a signal which combines the effect of boiler power and meirculation flow on bumout ratio, a limit on boiler power fm etion is not needed.

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We have mylewed the evaluation submitted with this aquest and have detemined that the methods used am conservative and that the mactor can be safely opemted with the specified limit based on bumout ratio. In order to clarify that the power-flow safety system setting is based on instrunent indications and the 1.5 burnout mtio limit is based on actual operating conditions, we find it necessary to add the indicated footnote to the new specifications. ,

TECHNICAL SPECIFICATIONS We therefom conclude that the technical specifications may be changed as follows:

(1) In Section 5.6.1 (b), delete:

" Boiler Power Hav!==

Steady State Power Tmetion of 190 Hwt 0.86" (2) In Section 6.1.4 (a), delete:

"(4) High mtio Beactor-power /rweirculation flow 30 Hw above 1 Hw(th) per 348 spm" (3) In Section 6.1.4 (b), add:

"High ratio 84 Hw above 1 Hw(th) per 443 spn Boiler power /recitrulation flow with minimum pemissible recirculation flow of 15000 gym.*

• This set point to be selected with appropriate conservative allowance for safety circuit instwment errors, uncertainties in heat balance measuruments and un-certainties in detector calibration due to control tod and zweirculation flow i progmme utilized.

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CONCWSIONS l i

Based on the forweoing considerution, we have concluded that the Fr-;- ::1 Change No.13 does not prwsont significant hazards considerutions not i 6 desetibed or implicit in the hazards sunnary 1+i-i., and that there is reasonable assurance that the health and safety of the public will not be endansered.

. FOR 'nE: A1tHIC DOGY COMSSION j

Donald J. t i Assistant Director for peactor Operutiens  !

Division of Reactor Licensing l-l Date: May 26, 1967 t

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