ML20072S281

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Responds to RAI Made During 940803 Conference Call Re TS Change Request 218 .APRM Surveillance Data & Regression Analysis Computations Encl.Revised TS Pages in Sections 3.1 & 4.1 Affected by License Amend 169 Also Encl
ML20072S281
Person / Time
Site: Oyster Creek
Issue date: 09/02/1994
From: Keaten R
GENERAL PUBLIC UTILITIES CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20072S284 List:
References
5000-94-0037, 5000-94-37, C321-94-2022, NUDOCS 9409140024
Download: ML20072S281 (9)
v • d • e


Text

'

I GPU Nuclear Corporadon 4

Nuclear

=e;tr888 o

Forked River, New Jersey 08731-0388 609 971-4000 Writer's Direct Dial Number:

)

September 2,1994 5000 94-0037-C321-94-2022 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Gentlemen:

Subject:

Oyster Creek Nuclear Generating Station Docket No. 50-219 Facility Operating License.No. DPR-16 Response to Request for Additional Information Re: Technical Specification Change Request No. 218 dated May 12,1994 This letter is in response to the conference call with members of my staff conducted with Mr. Alex Dromerick and Mr. Sang Rhow of the NRC staff on August 3,1994. At that time, the APRM (Average Power Range Monitor) scram setpoint drift analysis supporting our request to revise the Channel Calibration interval from weekly to quarterly was requested. The approach taken in the analysis was to determine if high confidence exists that the Technical Specification limit would not be exceeded for the increased surveillance interval based on actual surveillance data. Attached to this letter are the APRM surveillance data (Attachment 1) and regression analysis computations (Attachment 2).

In the regression analysis, the slope (b) and intercept (a) of the regression line were computed based on the surveillance data (Y-axis) and the time interval between the surveillances (X-axis). The analysis follows:

o Using the 'a' and 'b' (i.e., intercept and slope) values, the surveillance results are predicted at 3 months plus 25% margin (90 + 22.5 = 112.5 days) as follows:

ig=a+b*xg, where xg = 112.5 days Variance, s (i ), and standard deviation, s(t ), of the predicted value, 2

o g

g im, are calculated from the regression estimate, t, at 112.5 days.

g8l/

94o9140024 94o902 PDR ADOCK 05000219 f

PDR l

'GPU t/dckalCorporation is a subsidiary of General Pubhc Utihties Corporation i

I l

1 l

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]-

C321-94-2022 Page 2 1

l The 95% confidence range of the predicted value,t ), is calculated using o

g student-t distribution and standard deviation of the predicted value as follows-I

  • s(i )), for one-sided t and N-2 degrees of freedom i) t o

gm) g This methodology is based on " Applied Statistics for Engineers" by William Volk (Second Edition), published by Robert E. Krieger Publishing Company, Huntington. New York, 1

1980. Also, this methodology was used for revisions to Three Mile Island Unit 1 Technical Specifications extending the interval for performance of selected surveillances to coincide with a 24-month operating cycle. The NRC staff has approved this methodology in " Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Amendment No.175 to Facility Operating License No. DPR-50" transmitted by NRC letter dated June 23,1993. See paragraph 2.2 of the Safety Evaluation.

EVALUATION OF DATA & RESULTS

' contains surveillance test and calibration data for the scram function pertaining to all eight APRM channels.

I For APRM scram channels 1,3,4,5,6 & 8, AS-FOUND data for 25 weeks was within the specified tolerance and the AS-LEFT setpoint was adjusted only two times. These i

instances were for channel 4 (4/5/93) and channel 1 (9/26/93) where the AS-LEFT setpoint was adjusted although the AS-FOUND value was within the acceptance criteria in the surveillance procedure. Again,25 weeks of AS-FOUND data for these channels was within the acceptance criteria. Hence, these channels are considered acceptable for a quarterly Channel Calibration surveillance interval versus the current frequency of once every week.

l The setpoint for APRM scram channels 2 and 7 drifted outside the AS-FOUND acceptance criteria on three occasions (the Technical Specification limit was exceeded twice) over 25 surveillances for each channel, i.e.,3 times exceeding AS-FOUND acceptance criteria out of a total of 50 surveillances for these channels. The setpoints were adjusted to bring them within AS-LEFT criteria. Channels 2 and 7 are in different trip systems. Since all eight channels are identical in terms of hardware and function and as they share a common environment, four channels per trip system can be combined to determine a 95% Confidence Interval. As a simplified approach which provides conservative results, only the two channels whose setpoints were found outside

i 4

C326-94-2022 Page 3 AS-FOUND acceptance criteria were analyzed using the regression model by combining the two sets of data in a single analysis (see Attachment 2). Accordingly, for the combined channels 2 and 7, the 95% Confidence Interval is as follows:

112.92 to 115.22% - This range exceeds the AS-FOUND criteria in the surveillance procedure but is well within the Technical Specification limit.

l NOTE:

AS FOUND Requirement -

113 to 115% Reactor Power TECHNICAL SPECIFICATION Limit -

s115.7% Reactor Power l

Thus, there exists a 95% confidence that the Technical Specification limit will not be i

exceeded.

l Also enclosed as Attachment 3 are revised Technical Specification pages in Sections 3.1 and 4.1 which were affected by License Amendment No.169. That amendment deleted the scram and isolation functions of the main steam line radiation monitor (MSLRM).

The affected pages are 3.1-5, 3.1-6, 3.1-9, 3.1-10, 3.1-13 and 4.1-4. Page 3.1-6 is revised only as a result of pagination. These changes have been reviewed and approved by the NRC staff and do not alter Technical Specification Change Request No. 218 conclusions.

A reliability assessment was performed and documented in General Electric Report NEDO-31400A, " Safety Evaluation for Eliminating The Boiling Water Reactor Main Steam Line Isolation Valve Closure Function and Scram Function of the Main Steam Line Radiation Monitor", October 1992 which addresses the effect on scram and isolation reliability of eliminating MSLRM scram and isolation functions. The assessment is documented on page 25/26 of NEDO-31400A.

Sincerely, l

l R. W. Keaten Vice President and Director Technical Functions l

l cc: Administrator, NRC Region I l

NRC Senior Resident Inspector, Oyster Creek Oyster Creek NRC Project Manager l

l l

d 4

1

FUNC110N:

APRhl NITACHMENT1 INSTRUh1ENI': APRh11-8 PROCEDURE: 620.3.003 SECilON:

TEST DATA StIEET(E2-2 UE2-5) -

DATA SCRAh! SETFOINT AS FOUND AS 1.ElT I14 +/- 1%

(113 to 115)

APRh1 APRhi DATE 1

4 2

3 5

8 6

7 1

4 2

3 5

8 6

7 4/5S3 113.5 115 112.5 113 113 113 113.5 112.5 113.5 114 113 113 113 113 113.5 113 4/12B3 114 114.5 113.5 113.5 113 113 113.5 113 114 114.5 113.5 113.5 113 113 113.5 I13 4/1963 114 114 114 114 113.5 113.5 114 113 114 114 114 114 113.5 113.5 114 113 4/26S 3 114 114 113.5 114 113.5 113.5 113.5 113 114 114 113.5 114 113.5 113.5 113.5 113 5/2/93 114 114 113.5 113 113.5 113 113 113 114 114 113.5 113 113.5 113 113 113 5/1Q93 113 114.5 113.5 113 114 113 114 114 113 114.5 113.5 113 114 113 114 114 5/1733 113 114.5 113.5 113.5 114 113.5 114 114 113 114.5 113.5 113.5 114 113.5 114 114 5/24S3 113.5 114.5 113 113.5 114 113 114 114 113.5 114.5 113 113.5 114 113 114 114 5/3163 114 114.5 114 113.5 114.5 113.5 114 114 114 114.5 114 113.5 114.5 113.5 114 114 6/7/93 114 114.5 113 113 114 113 114 113.5 114 114.5 113 113 114 113 114 113.5 6/14/93 114 114.5 113.5 113.5 114 113 114 114 114 114.5 113.5 113.5 114 113 114 114 6/2163 114 114.5 116 114 115 114.5 115 116 114 114.5 115 114 115 114.5 115 115 6/28/93 114 113.5 114 114 113.5 113.5 114 113.5 114 113.5 114 114 113.5 113.5 114 114 7/563 114 114 114 114 114 113.5 114 114 114 114 114 114 114 113.5 114 114 7/12/93 113.5 114 114 114 114 113 113 113 113.5 114 114 114 114 113 113 113 7/19/93 114 113.5 113.5 114 114 113 113.5 113.5 114 113.5 113.5 114 114 113 113.5 113.5 7/26/93 114 114 113.5 114 114

-113 113.5 113.5 114 114 113.5 114 114 113 113.5 113.5 8/1/93 114 113 114 114 114 113.5 114 114 114 114 114 114 114 113.5 114 114 8/8/93 114 113.5 114 114 114 113 113.5 114 114 113.5 114 114 114 113 113.5 114 8/12/93 113 113 8/15S3 114 114 114 113.5 114 113 114 114 114 114 114 113.5 114 113 114 114 8/22/93 114 114 113.5 113.5 113.5 113.5 114 114 114 114 113.5 113.5 113.5 113 5 114 114 OC Surveillance

i FUNC110N:

APitM ATTACIIMENT 1 INSTilUMENT: Al'ItM l-8 t

PitOCEDURE: 620.3.003 SECllON:

TESTDATA SIIEET(E2-2 E2-5)

~

L DATA SCRAM SEFIDINT AS IOUND AS LEFT I14 +/- 17c (113 to,115)

APRM APRM

+

DATE 1

4 2

3 5

8 6

7 1

4 2

3 5

8 6

7 i

8/29/93 114 114 114 114 113.5 113 114 113.5 114 114 114 114 113.5 113 114 113.5 9/5/93 114 113.5 113 113 114 113 113.5 113.5 114 113.5 113 113 114 113 113.5 113.5 9/12/93 114 113.5 113.5 114 113.5 113.5 114 114 114 113.5 113.5 114 113.5 113.5 114 114 9/26/93 115 113.5 113.5 113.5 114 113 113.5 114 114 113.5 113.5 113.5 114 113 113.5 114 I

1

. OC Surveillance eie

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ATTACHMENT 2 APRM CilANNEl. 2 & 7 COMBINID l't.OW INDUCfD SCRAM SURVEll.1ANCE DATA Ell.2&Ull 01 1 Of[

gy

=} g=='9gg-g, g

~ ' ' ~ ~ ~

- ' = = = = =

ELAPSED DATA x

y v^ = v liSTIMATED Channel 217 y ^ = a + bX x-AVOx (x-AVGx) ^ 2 y-AYGy (y-AVGy)^ 2 (s-AVGs)*

y-y^

(y-y")^2 E* "'.

5 9

S 12-Apr -95 7

113.5 in629eS79:5 - 32.679245 1067.93307 - 0.2641509 0.00977572 8.63225347 - 0.1290579 0.oi6cdwm 19-Apr-95 14 114 113.657995 - 25.679245 659.423638 0.23584905 0.05562477 - 6.0564257 0.34200471 0.11696722 26-Apr-95 21 113.5 113.686932 - 18.679245 348.914204 - 0.2641509 0.06977572 4.93414026 - 0.1869326 0.03494381 02-May-95 27 113.5 113.711736 - 12.679245 160.763260 - 0.2641509 0.06977572 3.34923460 - 0.2117361 0.M483217 10- May-95 35 113.5 113.744807 - 4.6792452 21.8953364 - 0.2641509 0.06977572 1.2 % 02705 - 0.2448073 0.05993064 17-May-95 42 113.5 113.773744 2.32075471 5.38590245 - 0.2641509 0.06977572 - 0.6130295 - 0.2737447 0.07493617 24-May-95 49 113 113.802682 9.32075471 86.8764684 - 0.7644509 0.58392666 - 7.1224635 - 0.8026820 0.64429854 31-May-95 56 114 113.831619 16.3207547 266.367034 0.23584905 0.05562477 3.84923460 0.16838054 0.02835200 07-Jun-95 63 113 113.860556 23.3207547 543.857600 - 0.7641509 0.58392666 - 17.820576 - 0.8605568 0.74055803 14-J un-95 70 113.5 113.889494 30 3207347 919.348166 - 0.2641509 0.06977572 - 8.0092559 - 0.3894941 0.15170571 21 -J un-95 77 Ito 113.91M31 37.3207547 1392.83873 2.23584905 4.99902100 83.4435742 2.08156846 4.33292726 21-Jun-95 0

115 113.600120 - 39.679245 1574.44250 1.23584905 1.52732289 - 49.037557 1.39987943 1.95 % 6243 28-J un-95 7

114 113.629057 - 32.679245 1067.93307 0.23584905 0.05562477 - 7.7073691 0.37094207 0.13759802 05-Jul-95 14 114 113.657995 - 25.6'9245 659.423638 0.23584905 0.05562477 - 6.0564257 0.34200471 0.11696722 12-Jul-95 21 114 113.686932 - 18.679245 348.914204 0.23584905 0.05562477 - 4.4054823 0.31306735 0.09801116 19-J ul-95 28 113.5 113.715870 - 11.679245 136.404770 - 0.2641509 0.06977572 3.08508M5 - 0.2158700 0.04659986 26-Jul-95 35 113.5 113.744807 - 4.6792452 21.8953364 - 0.2641509 0.06977572 1.23602705 - 0.2448073 0.05993064 l

01 - Aug-95 41 114 113.76 % 10 1.32073471 1.74439302 0.23584905 0.05562477 0.31149875 0.23038917 0.05307917 l

Ok-Aug-95 48 114 113.798548 8.32075471 69.2349590 0.23584905 0.05562477 1 96244215 0.20145181 0.04058283 15-Aug -95 55 114 113.827485 15.3207547 234.725525 0.23584905 0.05562477 3.61338554

0. t"$ 1445 0.02976123 22-Aug-95 62 113.5 113.856422 22.3207547 498.216091

- 0.2641509 0.06977572 - 5.8960484 - 0.3564229 0.12703728 29-Aug -95 60 114 113.885360 29.3207547 859.706657 0.23584905 0.05562477 6.91527233 0.11463973 0.01314226 05-Sep-95 76 113 113.914297 36.3207547 1319.19722 - 0.7641509 0.58392666 - 27.754538 - 0.9142976 0.83594015 12-Sep-95 83 113.5 113.943234 43.3207547 1876.68778 - 0.2641509 0.06977572 - 11.443218 - 0.4432349 0.19645725 26-Sep-95 97 113.5 114.001 09 57.3207547 3285.(M92

- 0.2641509 0.06977572 - 15.141331

- 0.5011097 0.25111094

(

4/5/93 0

113 113.600120 - 39 679245 1574.44250 - 0.7641509 0.58392666 30.3209327 - 0.6001205 0.%014469 l

4/12h3 7

!!3 113.629057 - 32.679245 1067.93307 - 0.7641509 0.58392666 24.9718761

- 0.6290579 0.39571387 4fl9/93 14 113 113.65 7995 - 25.679245 659.423638 - 0.7641500 0.58392666 19.6228195 - 0.6579952 0.43295779 I

4,26S3 21 113 113M6932 - 18.679245 348.914204

- 0.7641509 0.58392666 14.2737629 - 0.6869326 0.47187646 l

5,2/93 27 113 113.7117 % - 12.679245 160.763260 - 0.7641509 0.58392666 9.68885724 - 0.7117361 0.50656827 5/1093 35 114 113.744807 - 4.6792452 21.8953M4 0.23584905 0.05562477

-1.1035955 0.25519262 0.06512327 5/17/93 42 114 113.773744 2.32073471 5.38590245 0.23584905 0.05562477 0.5A734781 0.22625526 0.05119144 5/2493 49 114 113.802682 9.32075471 86.8764684 0.23584905 0.05562477 2.19829120 0.19731790 0.0389M 35 5/31/93 56 114 113.831619 16.3207547 266.367034 0.23584905 0.05562477 3.84923460 0.16838054 0.02835200 67/93 63 113.5 113.860556 23.3207547 543.857600 - 0.2641509 0.06977572 - 6.1601993 - 0.3605568 0.13000121 6/14 93 70 114 113.889494 30.3207547 919.348166 0.23584905 0.05362477 7.15112139 0.11050582 0.01221153 621S3 77 116 113.918431 37.3207547 1392.83873 2.23584905 4.99902100 83.4435742 2.08156846 4.33292726 6,21/93 0

!!5 113.600120 - 39.679245 1574.44250 1.23584905 1.52732289

-49.037557 1.39987943 1.95 % 6243 6,2893 7

113.5 113.629057 - 32.679245 1067.93307 - 0.2641509 0.06977572 8.63225347 - 0.1290579 0.01665594 6/28N3 0

114 113.600120 - 39.679245 1574.44250 0.23584905 0,05562477 - 9.3583125 0.39987943 0.15990356 7/5/93 7

114 113.629057 - 32.679245 1067.93307 0.23584905 0.05562477 - 7.7073691 0.37094207 0.13759802 7/12/93 14 113 113.657995 - 25.679245 659.423638 - 0.7641509 0.58392666 19.6228195 - 0.6579952 0.43295779 7/1943 21 113.5 ll3 M 6932 - 18.679245 348 914204 - 0.2641500 0.06077572 4,93414026 - 0.1869326 0.03494381 7126 9 3 28 113.5 113.715870 - 11.679245 1% 404770

-0.2M1509 0.06077572 3.08508365

- 0.2158700 0.04659986 8/1/93 34 114 113.740673 - 5.6792452 32.2538269 0.23584905 0 05562477

-1.3394446 0.25932653 0.06725025 8/8/93 41 114 113.76 % 10 1.32075471 1.74439.302 0.23584905 0.05562477 0.31149875 0.23038917 0.05307917 8/15N3 48 114 113.79M548 8.32075471 69.2349590 0.23584905 0.05562477 1.96244215 0.20145181 0.04058283 8/22 S 3 55 114 113.827485 15.3207547 234.725525 0.23584905 0.05562477 3.61338554 0.17251445 0.02976123 l

8.2983 62 113.5 113.856422 22.3207547 49&216091 - 0.2641509 0.06977572

~5.8960484

- 0.3564229 0.12703728 9/5/93 69 113.5 113.885 % 0 29.3207547 859.706657 - 0.2641509 OM977572 - 7.7451050 - 0.3853602 0.14850253 9/12N3 76 114 113 914297 36.3207547 1319.19722 0.23584905 0.05562477 8.56621573 0.08570237 0.00734489

=P3

.J3._. _ II4dl.3 94 3234 43.3207547 1876 M778 0.23584905 0.05562477 10.2171591 0.05676500 0.00322226 mym AVLRAGli L39 6792452J _113.764150j omemana, b__y122d STD. DEVI:

SUM (x-AVGx) ^ 2.

l[_37371.5471]

..,9.somm3gy s

  • 2(y" ) = h40516150 SUM (y-AVGy)^ 2:

21.3018867 SUM (x-AVGx)*(y-AVGy):

154.490566 SUM (y-y ^ ) ^2:

[ [ 20.6632 % ]8 SFRAPRM2 I

4 ATTACHMENT 2

~

APR,M. CllA..N. NE1 2. & 7 COMBINI.D. l'l O. W INDl:CED SCRAM SURVIJLIANCE DATA l Ell.2&f[PAGII2 OI 2 '

=

FLOW BIASED APRM SCRAM DATA 1

- CHANNEL 2 & 7 COMBINED l

Regression Output:

i h_l3.600120]

l Constant. a =

Std firrof Y Est

,_, 0 63652291 6

R Squared. r

  • 2 =

l 0.0299m m jj6

]

No.of Otmervations. N =

53 De,rees or Freedom. N-2 =

Si 5

115 i

X coerricienito b =

P~~sstE601 6

//

Std Err of Coef.

02653 5 I C

l14F hCU. IMMM 113~ W M W.- -

jbd.

wx D-E H.3-a

/'

"1--f) j D

D C

D U

112 I

I I

I 60 80 I 1bo 20 40 0

10 30 50 70 DAYS O SURVL. DATA + REGRESSION UNE avo..

39.6792452 avu.-avo.ca.

37371.5471 o VARIANCE OF ANY PREDICITD VALUE. Y(i)^.

s ^ 2(YO)* ) = s " 2(y")*{ l + (1/N) + { (AVGu -x(i))* 2 / SUM (s - AVGx)^ 2 } [

%11ERE x(i) = 3 MONT}{S + 25% = 90 dan + 22.5 days = 112.5 days 0.40516150 * [ 1 + (153) + { (33.4525301 - 112.5)^ 2 / 31035.1320 } l,

=

0.47029674

=

o Y ^ (La x(i) + 112.5 dap) = a + b

  • x(i)

Y^=

113.600120

+

02413390

  • 112.5 days 114.065185

=

CONI 1DEWCE RANGE OF Y ^ Fi 112.5 days

_N-2 =QJ.-VAllyNE-SIDEg o

=Ya pt x(i) + 112.5 dap) +/- t( ALPilA. DEGREES OFIREEDOM)* a(Y(i))

4n 1.684 114M5185

+/-

(.05.N-2)

  • a(Y(i)). FOR TWO-SIDED t. or

($ _

1671

=

t(.1 N-2)

  • s(Y(i)). FOR ONE-SIDED t. %11ERE N-2(_ $1[

L677 - BY INTERPOLATION Il4M5185

+/-

=

114M5155

+/-

1.677

  • SORT (

0.47029674 )

=

114.065185

+/-

1.15005616

=

]

f CCE_l'! ANCE CRITERI A:

112.915129 to 115.215241 A

=

I AS-FOUND: 114 +/- 1%

TECil SPEC LIMIT: < OR = 115.7%

REI ERENCES:

o STANDING ORDER #1(R.64) lo TECil SPEC PARA. 2.3 lo PROCEDURE 620 3 001 l

CONCid'S10N TIIE COMBINED CilANNELS DO NOT SA11SFY lilE 'AS-FOUND* ACCEI'IANCE CRITERIA BUT ARE NOT IN VIOLA 110N OF TLCil SPEC LIMil.

NOTES:

o SilADED NUMBERS SilM.L BECilECKED FOR ACCURACY o BOXED VAIXES ARE USED IN Till5 CALCULAT10N e.g X " 2 REPRESEN13 X-squared o

SFRAPRM2

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