ML20101E456

Proposed Tech Specs Re Internal Corrosion of Diesel Generator Fuel Oil Storage Tanks

ML20101E456
Person / Time
Site:	Catawba
Issue date:	12/21/1984
From:	DUKE POWER CO.
To:
Shared Package
ML20101E436	List: ML20101E432 ML20101E456
References
NUDOCS 8412260259
Download: ML20101E456 (5)

Text

A ,

0 ELECTRICAL p0WER SYSTEMS SURVEILLANCE REOUIREMENTS (Continued) during this test. Within 5 minutes after completing this 24-hour test, perform Specification 4.8.1.'1.2g.6)b);*

8) Verifying that the auto-connected loads to each diesel generator do not exceed ^" ; " _

_ i --  : kW; 6760

9) Verifying the diesel generator's capability to:

a) Synchronize with the offsite power source while the generator is loaded with its emergency loads upon a simulated restoration of offsite power, b) Transfer its loads to the offsite power source, and c) Se restored to its standby status.

10) Verifying that with the diesel generator operating in a test mode, connected to its bus, a simulated Safety Injection signal overrides the test mode by: (1) returning the diesel generator

• to standby operation, and (2) automatically energizing the emergency loads with offsite power;

11) Verifying that the fuel transfer valve transfers fuel from each fuel storage tank to the day tank of each diesel via the in-stalled cross-connection lines;

12) Verifying that the automatic load sequence timer is OPERABLE with the interval between each load block within the tolerances given in Table 4.8-2;

13) Verifying that the voltage and diesel speed tolerances for the accelerated sequencer permissives'are 92'.5 1% and 98 + 1%,

respectively, with a minimum time delay of 2 0.2 s; and

14) Verifying that the following diesel generator lockout features prevent diesel generator starting only when required:

a) Turning gear engaged, or b) Maintenance mode. j l

• If Specification 4.8.1.1.2g.6)b) is not satisfactorily completed, it is not necessary to repeat the preceding 24-hour test. Instead, the diesel generator may be operated at greater than or equal to 5600 kW but less than or equal to 5750 kW for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or until operating temperature has stabilized. l

~

8412260259 841221 PDR ADOCK 05000413 P PDR CATAWBA - UNIT 1 3/4 8-6

4

1. - c 1.c

.3 ' ELECTRICAL POWER SYSTEMS SURVEILLANCE REQUIREMENTS (Continue )

0 7

dEJd o o

yG c h. At least once per 10 ' years or after any modifications which could

-affect diesel generator interdependence by starting both diesel g 1j 2-

. generators simultaneously, during shutdown, and verifying that both w 706 1.r. yo g yf g diesel generators accelerate to at least 441 rpm in less than or equal to 11 seconds; and , 4

l$ { { g gi. At least once per 10 years by:

W j q t0 EJ 1) Draining each fuel oil storage tank, removing the accumulated 3ry3 o9t j, c L

, sediment and cleaning the tank using a sodium hypochlorite solution or its equivalent, and

• Y/ jda'- R U

1 2) Performing a pressure test of those portions of the diesel fuel

1. 1 oil system designed to Section III, subsection ND of the ASME

@E )J, [S } .f Code at a test pressure equal to 110% of the system design f ressure.

Y N4.8.1.1.3 Reports - All diesel generator failures, valid or non-valid, shall be dE9 3 reported in a Special Report to the Commission pursuant to Specification 6.9.2 g within 30 days. Reports of diesel generator failures shall include the informa-a tion recommended in Regulatory Position C.3.b of Regulatory Guide 1.108, Revi-sion 1, August 1977. If the number of failures in the last 100 valid tests (on a per nuclear unit basis) is greater than or equal to 7, the report shall be C supplemented to include the additional information recommended in Regulatory-Position C.3.b of Regulatory Guide 1.108, Revision 1, August 1977.

4.8.1.1.4 Diesel Generator Batteries - Each diesel generator 125-volt battery bank and charger shall be demonstrated OPERABLE:

a. At least once per 7 days by verifying that:

1) The electrolyte level of each battery is at or above the low mark and at or below the high mark,

2) The overall battery voltage is greater than or equal to 125 volts on float charge, and

3) The individual cell voltage is greater than or equ.a1 to 1.36 volts on float charge.*

b. At least once per 92 days and within 7 days after a battery discharge with battery terminal voltage below 110 volts, or battery

overcharge with battery terminal voltage above 150 volts, by L verifying that

1) There is no visible corrosion at either terminals or

{ connectors, and lC l *Two different cells shall be tested each month, i

l l CATAWBA - UNIT 1 3/4 8-7 l

,,.,e- -- , - , , <

$',q ~

Y,~ '

, l 3s

w ' '

'l

.~ '

~w

- DUKE POWER CoxPAmy '

r y , .

p.o. mox asses :

y~ c 7 :m ~

cuAararra, w.c. ses4e r . K l EAL B.TUGEER 1 tutzenown Y d # ""

November 21.-1984 i"

,Mr.LHarold R. Denton 1 Director

{ Office ~of~ Nuclear Reactor Regulation

'U. S. Nuclear Regulatory Commission

- . . . ' Washington, D._C. 20555: .

iAttention: Ms. E. G. Adensam,' Chief _

r

' Licensing Branch No.-4 Re:' Catawba Nuclear Station 1 Docket Nos. 50-413 and 50-414 J

Dear-Mr. Denton:

" 1 License Condition 20,-Internal Corrosion Protection for Fuel Oil Storage Tanks,s

~

'which islincluded in the preliminary draft of. Facility Operating License NPF-31

'for Catawba Unit 1, would require the' application of an internal corrosion 1 protection'to theLfuel oil storage tanks prior to startup following the first refueling outage or the submittal of justification for not coating = the tanks.

D

Thelfollowing discussion summarizes Duke Power Company's position that an-internal-tank coating is not necessary. Also included

is a response to

- Ms. Elinor G. Adensam's letter of November 7,1984.

D- System Description

~

_ cThe dieshi fuel oil system at Catawba includes four 45,000 gal, storage tanks 4;y;Eper unit or.:2= tanks per diesel. The tanks are fabricated from 3/8 inch nominal thickness carbon steel which includes a 1/32 inch corrosion allowance. Each

~

.. tank is approximately 12 feet in diameter and-buried under approximately 5 1='

feet of backfill:and a concrete pad. The Unit I fuel oil' tanks-were coated with motor oil following sand blasting and were filled with fuel oil in March 1980. _

A recirculation.and purification system takes suction from the flush mounted

sample connection on-the bottom of the tank and discharges the fuel oil at a rate'of 25 gpm through a simplex filter (25 micron particle removal

rating)'. The' supply lines to the day tank are connected by an outlet raised 6 inches above the bottom of the tank.

No' Regulatory' Basis for Internal Tank Coating As' discussed in Section 9.5.4.2 of the Catawba SER, the Staff concluded that

" Internal corrosion. protection for the fuel oil storage tanks, as required

- by_ Section 7.5 of ANSI Std N195, is not being provided". Section 7.5 of ANSI N195' states, " Protection against internal and external corrosion shall be provided.". On March 24, 1982 Washington Public Power Supply System requested an interpretation of this section by Mr. F. A. Dougherty, Chairman

~

y l

e; 2;['; - , 1 y i#k S 3 MrhHar51d R. Dentin, Dir,tetor

.

P  : November 21; 1984 '

,[

1. Page'Two- . . . .

f g, 8: -

m

'ANS 59.51. , f By an' unanimous vote of[ the connaittee, an internal corrosion tallowance was deemed to meet the requirements of Section.7.5. Therefore.

-ANSI N195:was not'an appropriate basis for requiring an. internal tank <

cpating.-lIt'is our opinion that, contrary to Mr. Denton's April 28.-.1982 .

^ Office. Letter No. 2.-Revision ~2 that stated that'" Staff reviewers should not decrease nor:go beyond 'the scope and requirements of any specific SRP l section,: the Staff's requirement ' for an internal tank coating went beyond Kthe requirements'of the Standard Review Plan (NUREC-0800).

No Identified' Problem with Uncoated Tanks' The position'taken-by the Staff in the Catawba SER was based on an unsupported'

. . interpretation of. ANSI N195, not on plant. operating experience. 'At no time '

during the review. process has the-Staff identified any occurance of a problem-

with. uncoated, buried fuel oil storage tanks.- On the contrary, internally icoated fuel oil tanks at the Hanford N-Reactor and'at Limerick (See-INPO SER

'2-84) have experienced problems with flaking and peeling of the coating.

~

.Therefore License. Condition 20 would not enhance plant safety but may instead

= degrade plant' safety.

LDuke has had over 40 years experience with uncoated, buried fuel oil tanks at (the Company'sLfossil and nuclear-stations. Our experience with these tanks is

~ testimony to the~ reliability of uncoated tanks. Inspections of buried tanks at the~ Lee,'Cliffside, Allen and Marshall Steam Stations have shown that-sinternal corrosion is,not a problem.with buried fuel oil tanks. The survey of

~

.m  : local industries which was documented in'my letter of October 2,1984 further supports this conclusion.

Ju'stification for not Internally Coating' Catawba Tanks As a result of-the continuing controversy over License Condition 20,.a special inspection was performed on a 27,000 gallon underground fuel oil tank at Duke's

-Lee Steam Station. Details of this inspection were transmitted by my letter of 10ctober 2, 1984. After 34 years of service, minimal deterioration of the tank was noted. An ultrasonic inspection was made of the tank walls. Reductions in the mean tank wall thickness were noted at the top, bottom and sides of the tank Lof 0.0017, 0.0072, and 0.0002 inches, respectively. Based on the greater

reduction noted in the bottom of.the tank, a 1/32 inch corrosion allowance would 4

be exceeded.infan additional 113 years of service at the present. corrosion rate.

.It should be noted that the Lee fuel oil tank did not have the benefit of design and operating features to minimize corrosion such as:

1) Cathodic protection

-2)- Fuel oil sampling to limit amount of water in new fuel -

3) : Tank maintained nearly full

_ 4) Periodic (10 year) tank cleaning

'The results of the Lee tank inspection provides reasonable assurance that the

< Catawba fuel oil tanks will perform their intended function without the application

.~of an internal coating. As noted in previous submittals, the Catawba fuel oil tanks

have' additional design and operating features to further minimize tank corrosion:

7

~~ . 4 2.!'I

^ - Mr. Harold R4 Dentin, Dir:ctsr November. 21,41984'

, .Page Three f1) Cathodic protection (fully operable 6/85 for Unit 1)

-2) .'Use of high quality fuel

3) ; Tanks maintained nearly fulliin accordance with'the Technical Specifications.

4) Periodic'(Quarterly) drainage of accumulated water from the bottom of the tank

15) : Periodic (10 year) tank cleaning

-In order to provide further assurance that corrosion'of the buried fuel oil storage tanks at Catawba is not progressing at a faster. rate than expected, measurements of the tank wall thickness will be performed in conjunction with

-each 10 year cleaning. The measurement of the tank wall by ultrasonic ~or other means will include sufficient points to determine a statistical mean

~ thickness. . The resulting data will be evaluated and abnormal degradation (corrosion allowance exceeded) would be reported to the NRC pursuant to 10 CFR 50.73. LIn addition to the inspections during the 10 year cleaning. -

the Catawba Unit 2 tanks will be inspected prior to fuel load. . .

Conclusion Based on the above discussions, it is concluded that. License Condition 20 has been satisfied in that an internal tank coating-is not necessary and

.there'is reasonable assurance that the uncoated tanks will provide an adequatedieselgeneratorfueloilsupply.

Very-truly yours, fb.f.AA'- ll(/

Hal B. Tucker ROS: sib cc: .Mr. James P. O'Reilly, Regional Administrator

^

Mr. Jesse L. Riley U.LS. Nuclear Regulatory Commission Region II Carolina Enviromental Study Group 854 Henley Place 101 Marietta Street, NW, Suite 2900 Charlotte, North Carolina 28207

, Atlanta, Georgia 30323 Robert Guild, Esq. NRC Resident Inspector P. O. Box 12097 Charleston, South Carolina 29412 Catawba Nuclear Station '

Palmetto Alliance 2135 Devine' Street Columbia, South Carolina 29205

._,-,~,,c.__.-----. - - - - - * =" ' * * ' ' - - -