2CAN108705, Application for Amend to License NPF-6,changing Tech Specs to Increase Refueling Water Boron Concentration & Corresponding Concentrations in Refueling Water Tank & Safety Injection Tank.Fee Paid

Application for Amend to License NPF-6,changing Tech Specs to Increase Refueling Water Boron Concentration & Corresponding Concentrations in Refueling Water Tank & Safety Injection Tank.Fee Paid

ML20236H122
Person / Time
Site:	Arkansas Nuclear
Issue date:	10/28/1987
From:	Tison Campbell ARKANSAS POWER & LIGHT CO.
To:	Calvo J Office of Nuclear Reactor Regulation
Shared Package
ML20236H125	List: 2CAN108705, Application for Amend to License NPF-6,changing Tech Specs to Increase Refueling Water Boron Concentration & Corresponding Concentrations in Refueling Water Tank & Safety Injection Tank.Fee Paid ML20236H142
References
2CAN108705, NUDOCS 8711030452
Download: ML20236H122 (11)

Text

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

ARKANSAS POWER & LIGHT COMPANY -  :

CAPIT0L TOWER BUILDING /P. O. B0X 551/LITTLE ROCK, ARKANSAS 72203/(501) 377 3525 l T. GENE CAMPBELL October 28, 1987-Vice President Nuclear Operations

+

l 2CAN198705 l

U. S. Nuclear Regulatory Commission '

7920 Norfolk Avenue i Bethesda, Maryland 20814 l l

ATTN: Mr. Jose Calvo, Director i Project Directorate IV

SUBJECT:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Technical Specifications Change Request Refueling Water Tank and Safety Injection Tank Boron Concentration Increase I

Dear Mr. Calvo:

l The Arkansas Power & Light Company (AP&L) hereby requests an amendment to i l its Operating License No. NPF-6 for Arkansas Nuclear One --Unit 2 with the j enclosed submittal of proposed changes to the Technical Specifications.

l These Technical Specification changes provide safety and operational l l

enhancements specifically suited to-future extended cycle cores at l ANO-Unit 2. We wish to implement these improvements in conjunction with  !

Cycle 7. Therefore, we would appreciate your review and approval of the i enclosed material so that the Operating License Amendment can-be issued prior to the start of our next. refueling outage which is scheduled to begin i- on February 12, 1988. The circumstances of this proposed. amendment,

~

1 i

however, are not of an exigent or_ emergency nature. ]

1 The proposed Technical Specification changes involve increasing the j refueling water boron concentration and the corresponding concentrations in i the refueling water tank'and-the safety injection. tanks. A~related change -j l proposed in a concurrently submitted amendment . request .will decrease the- j l boric acid concentration of the boric acid makeup tanks. These changes l offset more reactive cores which have been utilized to extend cycle length- ]

4 for the plant. The proposed changes therefore assure that adequate safety j margins are maintained. q 8711030452 871028 i- g l 1 PDR ADOCK 05000368L j P PDR; a

'l ueusea uccx.a sours urnmes sysreu ker.V WM @O* 80

= __

-j a

LMr. Jose Calvo - October 28, 1987-AP&L has evaluated the proposed changes'in acc'rdance o with 10CFR50.91(a)(3) l using the criteria in 10CFR50.92(c) and has determined that these changes

' involve'no significant hazards consideration. The bases for these ,

determinations are included in the enclosed submittal.  ;

A copy of this amendment request and enclosure has been sent to.

Ms. Greta Dicus, Acting Director, Division of Environmental Health Protection, State Department of Health in accordance with 10CFR50.91(b)(1).

A check in the amount of $150.00 is included herewith as an appl _ication fee in'accordance with 10CFR170.12(c).

Very truly yours, AWm h 9

-U T. Gene Campbell f

TGC/sd f

Attachments / Enclosures cc: Ms. Greta Dicus, Acting Director Division of Environmental Health Protection State-Department of Health j 4815 West Markham Street 9

Little Rock, AR 72201 , .

1 i

i

\.

i i

L___A.. ._ - .m

.x .

.n ,

, s.;

?

;Q '

l; , ' T: ,

r

,q 1

yj y a J _

,v < .. 4 '

1

, o: ,

r .x -

,u iSTATE 0'F"ARKANSASL N 'ifj

. .):. SS '

COUNTY: 0F PULASKI' ) , , ,

,. -I, T.' Gene' Campbell. being duly sworns subscribe;to;and say,that-.I,am' :g-

p.  !

q Vice. President, NuclearL0perations, for. Arkansas. Power & LightLCompany;.that? <

l I have full authority to executeL.this oa'th'; that-I have~ fea'd' the document'.-

.numbereo:2CAN198705'and know the contents'thereofi aiid'that't'o thelbsst ofH s my1 knowledge, i_nformation and' belief the statements;in it are'true. .

l i

AAn f }

.T. Gene'Campbe

-i i

' fi l

SUBSCRIBED AND SWORN T0 before' me, a Notary Public in and for the 1 CountyandStateabovenamed,this2h' day.of.Oc-Koen .

1987, I

f.

( '

h/)& {.

N NotaryUublic 1

4

, 'M -Commission Expires:

~

W aqq3, p'  :

l-

.s '

1

_ . _ _ . _ . . _ _ _ _ . . _ _ _ _ .__.___._._._____.m. _ _ _ _ _ . _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ ._ m - . J

',. m ;

,& a'h',v .n;

< - au nf '

4 s

, g,'

w. 13'

. . _,___ _, - a a_r

..)

' ~ I 0!j -;

'({u,- 1 g. j, 'l j,g';i' - :P'.{ .

j.. f,,/. ' ' s .

..~)[{

- g ., , >

. s s ,

%c-. . .

., w, a

r s

e <

n '

n :- ' f ",. '

W ji uf';i. -

o i- +

L.a . .;^ <

.1 $IS t 4

/; f,si.'-. s t

., 3 _ ..t. , , ,

0 4 I i , - 'i- .

1. , , 1 - a i

i- 1 )

, , ,, , , [..

A f {.

, \- ,.'} .

1 3..- , .,

'f JL g'

.m ,

m. -

g> <

m1 3 3 e

i; 1'

m 4

.  : r. -

i , , -- i. .3:1, -.j ;

~

(l ~~

L ENCLOSUREL ,

l c-

~ PROPOSEDTECHNICAL SPECIFICATION ( ..

.+  ;^'

ANDS

.- g l.

RESPECTIVE SAFETY L _ ANALYSES:

' IN -THE MATTER OF ; AMENDING - 'i

.e ' LICENSE NO. NPF.6' ARKANSA'S POWER &LLIGHT: COMPANY ARKANSAS'NUCLEARLONE, UNIT 2 DOCKET N0,.50-368- ,

'l r-r 1' .j

'3-s i !A L

i 5 , , i s t- -; I J -

• 4 > . . . . . . , , . . .. . . * )

. . . . .I#  ; _ ,,. , ,  ; i r. .- . .,

i PROPOSED' CHANGES The proposed amendments would change ANO-2 Technical Specifications'3.1.2.7,.

3.1.2.8,.3.5.1, 3.5.4, and 3.9.1 to. increase required boron concentrations in the . refueling water tank and thel safety' injection tank and the minimum refueling water boron concentration. Corresponding changes are also <

proposed for Technical. Specifications' 3.1.1.1,.3'.1.1.2 and 3.10.1 to conform; with the proposed boron concentration changes. Bases sections 3/4.1.2, . 1 3/4.5.1, 3/4.5.4, and 3/4.6.2.2 are also revised'by;the proposed amendments-to discuss the bases.for the modified TechnicalJSpecifications. : Copies'of-the proposed revisions are included in Attachment 1. -RevisedITechnical Specifications 3.1.2.7 and 3.1.2.8 and. Bases : 3/4.1'.2 also ;contain changes from the concurrently submitted amendment request on the reduction of. boric acid makeup tank boron concentration. Attachment 2 provides further; '

description of the' prop' osed changes and. clarifies the source of each changeq ,

L DISCUSSION .I The increase in Cycle. 7 fuel reactivity and the corresponding increase in.

critical boron concentrations prompted a re evaluation 'of the boron' dilution -

event. The analysis was performed in accordance.with, and the results.of! J the re-evaluation were compared to, the. reference, analysis of' Cycle 2. ;The j reference analysis was: developed by Arkansas Power.& Light-(AP&L) and reviewed by the NRC as a part of the Cycle'2 Reload Report. .The reference analysis established conservative margins for.the-time.available to the-  ;

operator to detect and terminate a boron dilution event.

To maintain the conservative margin established in'the reference' analysis

~

'I for the limiting case of a boron dilution event during refueling, the refueling boron concentration is being' increased. Corresponding increases in H the concentration of the refueling water tank (RWT) and the safety injection :i tank (SIT) assure that the refueling boron concentration is maintained' '

l The conservative margin for the other limiting case.of a boron dilution )

event during Mode 5 with the RCS partially drained..is also, maintained by-i using more realistic input assumptions. . The beginning of life-(BOL) inverse q boron worth was assumed which corresponds to the most. limiting. time of life: ~;

conditions for the event. The analysis for Modes 3, 4 and 6 used the'very  ;

conservative end of life (EOL) worths. The volume of water which must be- a diluted was also increased to include the volume of one train'of shutdown-cooling which is required to be. operating-by Technica.1 Specifications in i this condition. Both of these realistic input assumptionsLare in conformance with Standard Review Plan Section 15.4.6. l i

The analysis of the boron dilution event for the less limiting cases of . .;

Modes 2-4 demonstrates that the operator will still have adequate. time to -!

detect and terminate the event.

All physics calculations for Cycle 7 at ANO-2 were performed using the increased boron concentrations for the refueling water tank and-the safety injection tank.

l

,i

-____a .

)-

'I

-1 DETERMIN'ATION OF SIGNIFICANT HAZARDS' g Arkansas. Power & Light Company has' performed an analysis of th'e proposed change in accordance with 10 CFR 50.91(a)(1) regarding no significant i hazards consideration using the standards in.10 CFR 50.92(c). A discussion of those standards as they relate to this' amendment' request follows: 1

'/

Criterion'1 - Does.Not Involva.a Significant Increase in the Probability or ,

Consequences of an Accident Previously Evaluated l The possible impact of. increasing the minimum refueling water boron. ~l concentration and the boron concentration in the refueling waten tank and 1 the safety injection tanks was considered"fer all SAR Chapter 15 events. J Additional evaluations were performed with Mpect to:a) effect sipSAR Chapter 15 boron dilution event analysis, b) offect o'n SAR Chapter 15 steam line break analysis, c) effect on SAR Chapter 15 steam generator tube rupture analysis, d) effect on long' term boric pcid buildup calculation reported in SAR Chapter 6,'and e) effect on pos 6 LOCA containment pH value i reported in SAR Chapter 6.

The re-analysis of the boron dilution event used design. data'for ANO-2' Cycle 7 and the higher boron concentrations jn the refueling water tank as i inputs for the analysis. The assumptions lfor critical boron concentration,  !

inverse boron worth and shutdown margin used in the re-analysis are compared i to the assumptions used in the Cyc h W analysis in Table 1. . The Cycle 2-analysis has been used as the refsente analysis for Cycles 3-7. Except for-the inverse boron worth and dilution volume used 'in the analysis for Mode 5, all other assumptions in completing the boron dilution event analysis are consistent with the conservative assumptions made in'the reference analysis.

s As discussed in Chapter 15 of the ANO-2 SAR, several conservative assumptions have been incorporated into the boron dilution event analysis.

The dilution flow assened in the analysis is 132 gpa which corresponds to the operation of all three charging pumps. Simultaneous injection from'all three pumps is highly unlikely. In addition, for the analysis during refueling operations (Mode 6),.it is assumed that all control element assemblies (CEAs) are withdrawn from the core. This is highly unlikely 7 since typically only those CEAs associated with fuel assemblies which are ,

being replaced or repositioned in the core would be removed.

}.j, Very conservative. values have been used for critical boron concentrad on and the inverse boron worths as shown in Table 1. These choices produce the most adverse effects by reducing the calculated time to criticality for initially subcritical.' modes. The more realistic beginning of cycle inverse boron worth was assumed for the cold shutdown1 (Mode 5) boron dilution-event analysis. >

The cold shutdown analysis conservatively assEnesthe. water volume:in the reactor vessel only up to the. lower lip of.the outlet nozzle. This .,

assumption considers the possible effects of a dilution. event during .  !

maintenance activities with the RCS drained,, The Cyde 7 ecalysistincludes'-  !

the volume of water of one shutdown cooling loop whit 6 sould be in service n in this condition as required by Technical Specifick(f E i

(l '

f' J r'

.lI T

Q' u

. o. b, 1'

yp g --

,i~ .* [

qj i

J The results of the revised boron dilution event analyses'.are shown in Table-2. The amount of time available forithe operator to diagnose boron- 1 dilution events and initiate corrective action'.for the most limiting modes of< operation i.e., cold shutdown and refueling; is slightly greater for the Cycle 7 analysis. The decrease in timelto loss of shutdown margin for ,

Modes 2-4 is not significant since the operator.will.still have a .

substantial amount of time to diagnose the event and initiate corrective.' ,

action as is' apparent when compared to the acceptance criteria. i The results for Mode'l are not presented since the reactor is. critical- when deboration starts. Power operation will be quickly terminated by the'  ;

Reactor Protection System. The results.of the Mode 2 analysis conservatively % und the event initiated in Mode 1.with respect to thel time to loss of shutdown-margin.  ;

The potential effects on the steam line break analysis due to the increase. I

" .in RWT and SIT boron concentration have been evaluated. The~ steam line-break results in temperature and pressure decreases in the primary system- ,

dt.a to rapid loss of energy to the secondary system through the affected.  !

, steam generator. The rapid temperature reduction results in a reactivity transient due to the moderator temperature coefficient. This transient is. I partially mitigated by the addition to:the reactor coolant system of borated water from the high pressure safety injection (HPSI) pumps and the safety injection tanks as reactor coolant system pressure drops below the HPSI injection pressure and the pressure in the safety injection tanks. The

~ increased boron concentration in the refueling water tank and'the safety 1 injection tanks will enhance the' mitigation of'this reactivity transient. a For the steam line break analyses, the proposed Technical Specification  ;

changes will in fact increase the margin of safety. These conclusions l include consideration of the separately proposed decrease in HPSI i

' ' differential pressure Technical Specification requirements. 1 The potential effects on the steam generator tube rupture analysis of.the L increase in RWT and SIT boron concentration have been evaluated. The steam l

generator tube rupture results in a decrease in reactor coolant system pressure. This results in actuation of the high' pressure safety injection l pumpt to maintain reactor coolant system pressure. The high pressure i injection pumps inject borated water from the refueling water tank into the a reactor coolant system. Since the reactor will be scrammed, the borated water actually provides a slight addition in shutdown margin. The proposed

Technical Specification changes therefore~have very little effect on this l transient other than to provide a slight increase in the margin of safety due to the minimal increases in reactor coolant system boron concentration.

- 3 The potential effects on the long term boric acid buildup calculations reported in Chapter 6 of the SAR have been evaluated. The calculation assumes the maximum inventories and concentrations of all borated water sources are available in the containment for concentration in the reactor vessel. Tr/2 proposed increase in RWT and SIT concentration would increase the total i wentory of available boron. AP&L is submitting a separate-

, request for a Technical Specification amendment to decrease.the boron concentration required in the boric acid makeup tanks (BAMT). This l

I

{-

l L .

. a C

1 -

s' N3 3.;,

1 i n, h.

4 ;j. 'q g ]

l O Technical Specification change request woulu 1cwar the BAMT regtfked boric s

(

acid concentration to 3.5% or.less. .This change will almost egacT1y offset LOCA theincreasedlhTandSITboronconcentrationinregardstocpos(echnical reactor coolan systemhoronconcentiathn. Thus the proadseG m c f

Specification d* ange for baron concentration in the. refueling yder tank ano* #

s

< the safety injedion t2rA will have no significant effrdt on the long term reactor coolant systerd boron concentration since boron concentration in the ,

boric acid m ke up, tank will be decreased, i The potd$ it effects on the, post LOCA containment pH vejue calculations

'}

) reportef p (itapder 6 of the 9R have been evaluated. Li.ke the long term 1

boric acid buildup calc %ations bisevased above, the post LOCA containment

x. pkwould by affected by an increas,e ja RWT . nd SIT boron concentration. The.

/ ' I'e reduction M BAMT boron concen kation also a 1 The resMt is d slight gduction in the plc,ulat spranand sump pH values.on pH.

o;se%the effect

• The maximum spray pH of 11.0 referul' erin TechMcahTprtrifications ~ basesg is-stiV1 bounding while the qinimum equil ium sump value of. 8.9 has decreased .

to 8.8. -The griginal decontaminatic, f @ actors for Jodine are jtill valid with,the reduced pH valv?s,so 4he ch sge has no signif'. b t,ispact on iodine:

/  ! rcaoval capabilities. Similarly, since the solut un is stTYL basi <, there is k no ,significant impact on containment corrosion characteristics. ,

, ) A ,a

\, Criterwh' 2 - V.'abes Not Create the Possibility of a Nor(or Different Kfnd of f ,. / R Accidentsfrom any Accident Previously Eu luated L i

IncreMdg.the rvfuelink watUr boron coricantration and the boron conadt' ration in the refdipg water tank and the safety injection tank does

/. not deate the possibility cf a new or different kind of accident. The increas8in boron concentration in the refueling water and the corresponding '

incretises ip tank concentrations 'r epresent a belatively minor change in plai.6 parah.eters 'which ar. laiwady coNrolled by Technical Specification f requirements ST,he base.(for these regiJirsM4ts do not ide'htify any limits

[, on maximum p g issible values of boron concentyetion. These changes have no effectonplantdesignjequipmentperformance'oroperatorresponseto i

j transients oi'accidenti. Therefore, these ch!qgea do not create the 7 -

potential for any unanalyzed accidents. b ,'

/< ' i )< z ,, s

\ i \

\

Criterion 3 - DoesNotInvolveaSignificantReductioninauMakinof Safety j CA T:

Increasing the refueijng water boron concentration and the cotAentrat4n of tt.Nrefueling water Vank and safety injectiostank will pr,t create. a '

significant reduction in a margin of safety. The retult',%f the Nnalyses supporting the inciensed boron concentrations indicate these changel msult in no significant impact on selety margin. \,

, '.\

For the boron dilution event, tN: timr available for the operator to diagnose the event and initia,te ' correct &ve act.on is slightly improved for i the limiting cases. The operator still has suhtartial time available in 3

the non-limiting cases so the decrease in time to loss of shutdown margin fnr Modes 2-4 is not significant.

i $ d 1

\

,i s s 4

?T 1,

- 4 di n

b A .. ',

't 1 J

s ) JN a ' f!

~

a) o

+

iu , 3 \,

lT

'T ( ')

A

<d  ; . . _ _ _ . _ _ .

l 9

i 1

The effect'of the boron concentration. increase on both the steam line. break analysis:and on the steam generator tube rupture analysis was positive. The- .;

injection of additional. boron for both events improves the analytical l results.

l 1

The decreased boric acid concentration of the boric acid makeup tank l proposed in the concurrently submitted amendment request offset the RWT and l SIT concentration increase'for the post LOCA. boron precipitation  !

calculations. There is essentially no change in calculated containment inventory and consequently no impact on the time requirements for. initiation .

of the core flush flow. .;

The minor reduction in post LOCA containment minimum calculated pH has j insignificant impact on both iodine' removal capabilities and corrosion characteristics.

Based on these results, the prop'osed' changes do not involve any significant reduction in a margin of safety. 1 CONCLUSIONS l

The Commission has provided guidance concerning the application of the L standards for determining whether a significant hazards consideration i exists. This guidance includes examples (51 FR 7750) of types of amendments-that are considered not likely to involve significant hazards s considerations. The changes proposed in this amendment are directly 1 comparable to examples provided by the Commission.

Example (iii) relates to a change resulting from core reloading. The proposed change in the refueling water boron concentration and the corresponding concentration changes in_the refueling water and safety injection tanks are analogous to this example. These changes are being implemented partially to offset higher core reactivities used to extend cycle duration and increase fuel burnup. These changes help to assure that acceptable margins established in analyses for previous cycle are not significantly decreased.

l l The Baltimore Gas and Electric Company submitted a similar amendment request I

for Calvert Cliffs dated September 22, 1980. This Technical Specification-

. request was subsequently approved.

Based on these evaluations, AP&L has determined that these proposed changes do not involve a significant hazards consideration.

f 1

_ _-____ - - _ _--__-__ Q

i TABLE 1 KEY PARAMETERS ASSUMED IN THE B0RON DILUTION ANALYSIS ~j REFERENCE' i PARAMETER; CYCLE CYCLE 7 (Cycle 2)

Critical Boron Concentration, PPM

(All Rods Out, Zero Xenon)

Power Operation (Mode 1). 1000 '1800' Startup (Mode 2) 1300 2000 Hot Standby.'(Mode 3) :1300 1900 Hot Shutdown (Mode 4) 1300 1900 Cold Shutdown (Mode 5) 1300 1610 Refueling (Mode 6)- 1250 1650' Inverse Boron Worth, PPM /%

Power Operation 82 82 Startup 82 82 l Hot Standby 62 62 L Hot Shutdown 62 62 .

l Cold Shutdown 62 80.7#** )

Refueling 62 62 Shutdown Margin Assumed, %

Power Operation 5.4 5. 0 Startup 5.0 5.0 Hot Standby 5.0 5.0 l

Hot Shutdown 5.0 5.0 ,

Cold Shutdown 5.0 ' 5. 0 l Refueling * **

i Technical Specification minimum refueling boron concentration of 1731.

i ppm minus a 50 ppm uncertainty is assumed.

• • Technical Specification minimum refueling boron concentration of 2500 ppm minus a 50 ppm uncertainty is assumed.

I *** For Mode 5, BOC physics data were used.

'T

?

,y > ,

4 i

W y

,. y ,

y q ;

7:~

?'

s < ,

+.;f - , ..

7 c. ) : +

. ,, . y ,

- ,n . s

'(Z ,

,g,

..:., , (.4

t . a ' (

,g:'1 TABLE 21 -

• +

l,. . ,, . .., ._ . . . . . .. .,

,I

','4 j,.

w

'{,

1

RESU, LTS 0F.,THE' BORON. DILUTION EV.ENT,

.. . W M<-'.

h '! 1 .7 7, i F: '

LAcceptsnce*i .

r ' TimeL ~ to: Lose Re' q uired ';. Criterial Mode" Shutdown Margin-(Minutes)7 2

-(MinutesF

n"

Reference 'C '

Cycle. Cycle7 -

7

"~

Startup (' Mode 2) ... 5202. 934 151 ,"

' Hot' Standby'(Mode 13) 1136~ 175?

15j E+

Hot Shutdown;(Mode 4)-. '135L 75: . 15:

Cnid Shut'down (Mode 5). 35 '

36 -15;

. Refueling,(ModeL6); ~40 ;55: 30 l

, y.

h I

• Acceptance criteria.from' Standard. Review Plan Section"15.4.6.

c

) ,

1]

=.

.)

i d

0 a u

.Jj ll

.h ll fl;

, .h 8

s 5

4 L,

, 4 1

9' z ', 7 [ ' .- f. -l: 'j r

2

-::p-