ML20137V312

Responds to 970409 Request That NRC Exercise Discretion Not to Enforce Compliance W/Actions Required in TS 4.18.5.b. NRC Has Concluded That NOED Warranted

ML20137V312
Person / Time
Site:	Arkansas Nuclear
Issue date:	04/11/1997
From:	Beckner W NRC (Affiliation Not Assigned)
To:	Hutchinson C ENTERGY OPERATIONS, INC.
Shared Package
ML20137V318	List: ML20137V312 ML20137V330
References
TAC-M98336, NUDOCS 9704170262
Download: ML20137V312 (5)

Text

. _ . _ . _ _ . _ .

e

p % ,1 6B/3  !

UNITED STATES j j j NUCLEAR REGULATORY COMMISSION  !

o WASHINGTON, D.C. 30eelH1001 '

l

+9

. . + ,o April 11, 1997 l

N0ED No. 97-6-009 I l

Mr. C. Randy Hutchinson i

Vice President, Operations ANO i Entergy Operations, Inc.

i 1448 S. R. 333 i Russellville, AR 72801 1

SUBJECT:

NOTICE OF. ENFORCEMENT DISCRETION (NOED)'FOR ENTERGY OPERATIONS, INC.

REGARDING ARKANSAS NUCLEAR ONE, UNIT 1 (TAC NO. M98336)

Dear Mr. Hutchinson:

By letter dated April 9 1997, (Attachment 1) you requested that the Nuclear  !

Regulatory Commission MRC) exercise discretion not to enforce compliance with j the actions required in Arkansas Nuclear One, Unit 1 (ANO-1) Technical Specification (TS) 4.18.5.b. That letter documented information previously discussed with the NRC in telephone conversations on April 8 and 9, 1997, and in an earlier draft of the request (Attachment 2). You stated that on April 8, 1997, at 8:12 pm CDT, you determined that the plant was not in compliance with TS Section 4.18.5.b and a reactor shutdown would be required in accordance with TSs 4.0.3 and 3.0.3. You requested that a Notice of Enforcement Discretion (NOED) be issued pursuant to NRC's policy regarding exercise of discretion for an operating facility, as described in Section VII.C, of the General Statement of Policy and Procedures for NRC Enforcement Actions" (Enforcement Policy), NUREG-1600.

For several years the progression of intergranular corrosion that had been detected in the steam generator tube sections located inside the upper tube sheet had been tracked at ANO-1. Eddy current test techniques were used to measure the extent of tube degradation caused by the intergranular corrosion.

Metallographic measurements of actual tube degradation were made on three tubes that had been removed from the B steam generator during refueli.ng outage IR13. These measurements indicated a systematic non-conservative bias of up to 50% through-wall in the eddy-current measurements of eleven patches of intergranular corrosion. Based on this data you concluded that it is possible th'at tubes were returned to service with degradation greater than 40%

through-wall, thereby exceeding the TS limit. Once this conclusion was reached, TSs 4.0.3 and 3.0.3 required reactor shut down to begin within 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />.

The NOED was' requested to authorize continued reactor operation until a TS i amendment is processed. The proposed TS amendment would give a one-time authorization to operate with tubes having intergranular corrosion indications  ;

exceeding the TS limit until the next refueling outage. In your evaluation of '

t;.e safety rationale for this request, you noted that all the degradation was j inside the tube sheet. You assessed the inspection results in the selection 9704170262 970411 PDR ADOCK 05000313 G PDR c  !

j

.1.

Mr. C. Randy Hutchinson i of the three tubes that you removed from the steam generator. The three tubes 1 1

removed were selected because the extent of intergranular corrosion was i determined to bound the degradation in the remaining tubes. In accordance with NRC Regulatory Guide 1.121, " Bases for Plugging Degraded PWR Steam Generator Tubes," tube structural integrity may be demonstrated by subjecting the tube to the larger of three times the normal operating differential pressure or 1.4 times the main steam line break differential pressure (3765 l psid for ANO-1). Tube leakage integrity may be demonstrated by subjecting the tube to the differential pressure the tube would experience under a postulated main steam line break (2500 psid for ANO-1). The three tubes that had been

removed from the steam generator in IR13 were subjected to pressure tests and 1 withstood pressures in excess of 10,000 psig without leaking or. bursting. You stated that rev'tew of eddy-current data over past cycles confirms that the

, patches of intergranular corrosion is exhibiting little or no growth. In

addition, based on eddy-curr ant testing, the tubes with the most severe

, intergranular corrosion were removed from service during the last refueling outage. Therefore, the results of the pressure tests are expected.to be representative of the performance of the tubes through the current operating i cycle and structural and leakage integrity over this time period is assured.

i The staff has concluded that the structural support provided by the tubesheet would preclude catastrophic tube failures resulting from flaws in this region i and, based on your pressure testing, tube leakage would not be expected even in the unlikely event of a main steam line break.

At.the start of the current operating cycle, you established conservative administrative criteria that require the plant to be shut down if primary-to-secondary leakage into the steam generator reaches 100 gallons per day. The TS limit is 500 gallons per day. Sensitive N-16 gamma monitors were installed for use during this operating cycle to measure radioactivity in the secondary

system and alarm in the control room if activity (leakage) is detected. These are effective compensatory measures to monitor steam generator tube leakage  !

! and support the authorization of continued power operation for the remainder  ;

of the operating cycle. l

, The anticipated worse case scenario resulting from the continued operation I with the existing tube flaws would be the development of a small primary-to-secondary leak. Any leakage would be detected in its incipient stage and the reactor would be shut down. Absent the N0ED, you would be required to shut ,

down the reactor and repair the steam generator tubes. Continued operation l with the existing tube flaw indications represents an insignificant risk and I does not warrant the transient resulting from an unnecessary plant shutdown. l Authorization of the NOED on this basis is consistent with criterion B.I.(a) of the NRC N0ED policy.

On the basis of the staff's evaluation of your request, the staff concluded ,

that an N0ED is warranted because we are satisfied that this action involves minimal o.' no impact to safety and has no adverse radiological impact on public health and safety. Therefore, it is our intention to exercise discretion not to enforce compliance with TS 4.18.5.b until May 7,1997, at 1

i

o 4 ,

April llo 1997 k ,

Mr. C. Randy Hutchinson 3:35 pm CDT, or until an amendment to TS 4.18.5.b is issued, whichever is '

sooner. This letter documents our telephone conversation on April 9, 1997, at 3:35 pm CDT, when we orally issued this notice of. enforcement discretion.

However, as stated in' the Enforcement Policy, action will normally be taken, to the extent that violations were involved, for the root cause that led to the noncompliance for which this N0ED was necessary. ,

Sincerely, ORIGINAL SIGNED BY:

William D. Beckner, Director Project Directorate IV-1 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-313 Attachments: As stated cc: See next page I

4 DISTRIBUTION: Docket File PDIV-1 r/f SCollins/FMiraglia i i PUBLIC RZimmerman MGamberoni EAdensam (EGAl) l JLieberman PGwynn, RIV GKalman

~

CHawes JRoe CGrimes ACRS OGC. 1 N0ED (E-mail) TGD (E-mail) i Document Name: AR198336198336LTR Yqg[ J OFC PMlh LA/PD4-1 D/PD4-1m h)[//kEI D/RIV/DRP l NAME/g GKalika)/ Chawed 7d WBecYn'h e ISheko/ PGwynnYM

~

DATY /[/ /97 [/ll/97 k/ l\/97 N(([/97 i /l /9k COPY YES/NO YES/N0 YES/NO YES/N0 YES/N0 ,f 0FFICIAL RECORD COPY '

Ol / l

170028 '

. . . = - - . -- .- - - . . . - - .- - .

Mr. C. Randy Hutchinson +

3:35 pm CDT, or until an amendment to TS 4.18.5.b is issued, whichever is sooner. This letter documents our telephone conversation on April 9, 1997, at 3:35 pm CDT, when we orally issued this notice of enforcement discretior.

.i However, as stated in the Enforcement Policy, action will normally be taken,

' to the extent that violations were involved, for the root cause that led to ,

the noncompliance for which this N0ED was necessary.

Sincerely, g er d, b

William D. Beckner, Director Project Directorate IV-1 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-313 Attachments

As stated cc: See next page I

i 1

s s

h j Mr. C. Randy Hutchinson  ;

Entergy Operations, Inc. Arkansas Nuclear One, Unit 1 '

I i

j cc: l 4

4

Executive Vice President Vice President, Operations Support l & Chief Operating Officer Entergy Operations, Inc.

i Entergy Operations, Inc. P. O. Box 31995 i P. O. Box 31995 Jackson, MS 39286-1995 Jackson, MS 39286-199

] Wise, Carter, Child & Caraway 1

. Director, Division of Radiation P. O. Box 651 l Control and Emergency Management Jackson, MS 39205

Arkansas Department of Health  !

! 4815 West Markham Street, Slot 30 J

Little Rock, AR 72205-3867 )

! l 4

Winston & Strawn i a ing C kb05-3502

.1 Manager, Rockville Nuclear Licensing Framatone Technologies

! 1700 Rockville Pike, Suite 525 l

Rockville, MD 20852 Senior Resident Inspector U.S. Nuclear Regulatory Commission P. O. Box 310 London, AR 72847 i Regional Administrator, Region IV U.S. Nuclear Regulatory Commission j 611 Ryan Plaza Drive, Suite 400 l Arlington, TX 76011-8064 County Judge of Pope County Pope County Courthouse Russellville, AR 72801

)

l l

4