ML20244A831

Forwards Davis-Besse Pressurizer Surge Line Thermal Stratification Phase I Program, Per Bulletin 88-011

ML20244A831
Person / Time
Site:	Davis Besse
Issue date:	06/02/1989
From:	Shelton D TOLEDO EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20244A834	List: ML20244A831
References
IEB-88-011, IEB-88-11, TAC-72128, NUDOCS 8906120165
Download: ML20244A831 (5)

Text

, .

- - - - - - - - - - - - - - - - - - - - - - - - - = - - - - - - - - - --

-y 4~' 0 y e" u , ,l ^

[

'l , ,

a TOLEDO EDISON

< r A Centerer Energy C:mpany Docket Number 50-346 DONALD C. SHELTON ,

Vme Prevders-Nacipe - l License Number NPF-3. ##

y, '

+ i.

Serial Number 1671 June 2,L1989 United States Nuclear Regulatory Commission Document Control Desk

, + Vashington, D. C. 20555

Subject:

. Toledo Edison's (TE) Response to Paragraph 1.b of Nuclear Regulatory Commission (NRC) Bulletin Number 88-11 and Justification for Continued Operation (TAC Number 72128)

Gentlemen':

Toledo Edison's initial response (Serial, Number 1633 dated March.3, 1989) to NRC Bulletin Number 88-11, " Pressurizer Surge Line Thermal Stratification,"'

I provided the results of.a visual inspection as requested in Paragraph 1.a. of l1 the Bulletin. In addition, the results of a' program that had been developed L and implemented-to assess whether (based on an evaluation of the condition of I

the surge line) Davis-Besse could be safely returned to power vere presented.

Based upon these efforts, TE concluded that,'in the short-term, the integrity of the surge line was not a concern.

Since the initial response, a number of preliminary analyses have been performed forL the purpose of demonstrating that Davis-Besse's st'rge line meets the applicable design' codes, and other Updated Safety Analyses Report (USAR) and' regulatory commitments for the licensed life of the plant. The results of these analyses, which included fatigue and stress evaluations, are documented I

in Attachment Number 1 and 2 (Davis-Besse Pressurizer burge Line Thermal Stratification, Phase I Program, dated May 3, 1989 and Babcock & Vilcox Owners Group Pressurizer ' surge Line Submittal for Nuclear Regulatory Commission L

Bulletin Fumber 88-11. " Pressurizer Surge Line Thermal Stratification", dated May 19P9, respectively).

L Uhile prelirirary analyses indicate that the surge line may not meet the

applicable design codes for the licensed life of the plent, the fatigue p calculations demonstrate tha t the Davf r,-Besse surge line is capable of R operating for 3.5 more yeats, even at a conservatively assumed rate of sin heatups end cooldowns per year, without exceeding ASME Code him2ts. It is noted that over the past 12 years Davis-Besse has averaged three heatups and cooldovns per year (see Attachment 2, page 5-6). Thermal stratification.

effects are calculated to result in a fatigue usage factor of 0.704 (of the l.

H possible 1.0) assuming a total of 40 heatup and cooldovn cycles through the sixth refueling outage, which is presently planned for February 1990.

THE TOLEDO EDISON COMPANY EDISON PLAZA 3DD MADISON AVENUE TOLEDO. OH!O 43652

' r

_0906120165 890602 (

PDR ADOCK 05000346

@- @SGC

- Docket Number 50-346 License Number NPF-3 Serial Number 1671 Page 2 Thermal striping is approximated to add 0.10 to the fatigue usage factor for the surge line over the design life of the plant. A more detailed evaluation is currently in progress to more accurately quantify the effect of thermal striping on fatigue usage. The results of this evaluation are scheduled to be submitted to the NRC by October 31, 1989.

Paragraph 1.b. of NRC Bulletin Number 88-11 requires that a justification for continued operation (JCO) be prepared snd submitted if analyses show that the surge line vill not meet the design code requirements or licensing commitments for the licensed life of the plant. To meet this requirement, TE has prepared a JC0 covering the period through January 2, 1991 (i.e., two years from receipt of the bulletin). By the end of this two year period, Toledo Edison vill have updated the surge lines stress and fatigue analyses to ensure compliance with applicable codes or vill submit a future JC0 and a description of proposed corrective actions to effect a long term resolution.  ;

The scope of the present JC0 includes not only the surge line and its terminal end nozzles, supports, and whip restraints, but also the surge line drain connection and its supports / restraints. A calculation (Calculation Number 99c, Revision C2, dated May 1, 1989) was performed to evaluate the effects of stratification induced movements on the integrity of the drain line and its supports / restraints. No concerns were identified as a result of this effort.  ;

Both the drain line and its supports / restraints continue to meet the original design basis limits.

The methodology used to prepare the following JC0 was to evaluate, and then l document, whether the continued operation (through January 2, 1991) of the surge and drain lines and their associated components vould involve any unreviewed safety questions as defined in 10CFR50.59(a)(2). Based upon the evaluation performed to date, Toledo Edison has concluded that there is adequate justification for continued operation of Davis-Besse through January 2, 1991 because:

- Use of the Surge Line through January 2, 1991 vill not increase the probability of an accident previously evaluated in the USAE because analyses have shown that j the pressure boundary and structural integrity of the l Surge Line and its associated compon2nts vill not exceed l code limits as a result of stratification or striping i j

during this period.

i

- Use of the Serge Line through January 2, 1991 vill not j increase the consequence of an accident previously t

f ,

l' evaluated in the USAR because no new failure modes are I I introduced, nor vill previously postulated accident; be af fected, during this periot'.

- Use of the Sutge Line through January 2, 1991 will not i j

increase the probability of a malfunction of equipment j

important to safety because fatigue usage of the nozzles at the equipment connections (Pressurizer, Hot Leg, and (

drain connection) vill remain below a limit of 1.0 and l l J no other equipment important to safety is affected.

_ _ _ _ _ __-_____-____-_- _ - _ - _ _ _ a

- Docket Number 50-346 License Number NPF-3 Serial Number 1671 u Page 3'

- .Use of the Surge Line through January 2, 1991 vill not increase the consequences of a malfunction of equipment important to safety because no new equipment malfunctions are postulated, nor are previously postulated equipment malfunctions adversely affected, during this period.

- Use of the Surge Line through. January 2, 1991 vill not create a possibility of an accident, of a different type than any previously evaluated in the USAR, because no new failure modes have been introduced. Further, operation of the plant vill be maintained within the limits analyzed in the USAR.

- Use of'the' Surge Line through January 2, 1991 vill not create a possibility of a malfunction of equipment.

different than any previously evaluated in the USAR because no different or additional equipment will be added nor is the configuration of applicable existing i equipment scheduled to be changed during this period.

- Use of the Surge.Line through January 2, 1991 will not reduce the margin of safety as defined in the basis for any Technical Specification because the structural and pressure. boundary integrity of the Surge Line, and its thermal end nozzles, supports / restraints, whip 1 restraints, and drain line and supports have been shown not to exceed any code limits during this time period.

l l Please contact Mr. R. V. Schrauder, Nuclear Licensing Manager, at (419) l 249-2366 if there are any questions.

i

, Very truly yours, f'

l.

~s s

/(/t/ (_,,

~~ ,

- 2h I

CFM/dlm i

Enclosures cc: P. M. Byron, DB-1 NRC Senior Resident Inspector

! A. B. Davis, Regional Administrator, NRC Region III ]

T. V. Vambach. DB-J NRC Senior Project Manager l l

)

i i

i l

l l l

j

_L-.----_...____---_-_---_.____ - _ - _ - - _ . - _ _ _ - - _ .- )

Dockst Number 50-346

+: License Number NPF-3 Serial Number 1671 Enclosure Page 1 RESPONSE TO PARAGRAPH 1.B 0F NRC BULLETIN 88-11,

" PRESSURIZER SURGE LINE THERMAL STRATIFICATION" AND JUSTIFICATION FOR CONTINUED OPERATION, FOR DAVIS-BESSE NUCLEAR POVER STATION UNIT NO. 1 This letter is submitted in conformance with Atomic Energy Act of 1954 Section 182a, in response to NRC Bulletin 88-11 " Pressurizer Surge Line Thermal Stratification".

By: L D. C. Shelfon, Vice Presidhnt, Nuclear Suorn and subscribeel before rae this 2nd day of June, 1989 l LJL k.,

Notary Public, State of Ohio {

k 4

lAUR!E A. HINKLE l Nobry Public. State of Ohio f,!y Commission Expires May 15,1931 l

1

( -__._________._._____._________________.________m

I 1

ATTACHMENT 1 DAVIS-BESSE PRESSURIZER SURGE LINE THERMAL STRATIFICATION PHASE I PROGRAM l

---

_ _ _ _- _ -