ML20045G688

Proposed Tech Specs Changes to Reduce Minimum Number of SGs Required to Be Opened for Insp During First Insp Following SG Replacement

ML20045G688
Person / Time
Site:	North Anna
Issue date:	07/02/1993
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20045G684	List: ML20045G683 ML20045G688
References
NUDOCS 9307150048
Download: ML20045G688 (6)

Text

.. . .--_ _ _ _ . ~ . . . .. .._ - --

I i

ATTACHMENT 2 4

h PROPOSED TECHNICAL SPECIFICATIONS CHANGES NORTH ANNA UNITS 1 AND 2 }

i VIRGINIA ELECTRIC AND POWE9 COMPANY t

i

~9307250048 DR 930702 V ADOCK 05000338 $

PDR l ,

s m f n a o

o it e t

%ehrces e dsen e e 2 N pt r t o s e e s ,e e ci t e r n n 3nshv t ec Y h O O gscie o re pu T srt nunns ns isoai es t i n sitvs a

premom so ei be l ht mpuh r ct e la o

c oinh r hw nt cat so erseht c l

t nl o efimep e of itl e or cl lu dt hs r v es e pha E ef hod e es o int ss ns B c s ne in N st urd eo O

T O gut oie l

ci t I

T e 1 ieh t

nsamf d i icv r e S C o e l art eo ep R E N

r l A e t o eebm ss O P h n rht o inn T s T O t ot e t t i

A af N d b sn R IN i

n) nll ie r

E ot nr ua f equ N

E C E r a eoh I

t ol nf s pne e he t

s 1

G V a e abc gb R r 4M 4 E ehmyn nt is nu r

E A s E N i

en e gi k a me uq u d dn T I i L

B S G mr slar ato nt oe s e s da eh A F N eaial t

ct r T O R I t

segremr p e pou R U e nin n sf E D B

n e r g as ogme ien h

MD t

o e oT U ET tomf a rea mh t n .

N C s depes ss n et e r n

o to o t

M EP it s esc r

U it s c imfoaer na ait r c e

npe M N e l I

p rsot s N

I eer I

M i s

n bbom ymt a ro c mu es gn i it n e aure eir md U ic v

mn n n c eeoh air eh r r nhg t t e

p e

s iot smiu nc sd n n - t o n e.

s o i cias e

pN e n r s wavo r

oe t

n o it c

t n sesid t

rd enb o

t a e e inrl t

in ho a i

r p u el d t c1 e eh a nU t

c e n s n

q e

c oesn p

G e I s - iwt ao c.s .s e i s e b v(h r

gon r hed n c u  :

n e st t f t he i

m i S o s e e iai nt o o gi br e

a e

v r it i nbt uaari t t c t e & a t e ienn cr ed hnc iv S s t hedpeo cis r r f i n d N

o Ttihn ogc aue Edd e o n s t o e

r o

. s r c e le . .

P N i

b 1 2 F S a T

ZOUf$f CZ5 " gE p%

Z O

d

'c

• y TABLE 4.4-1 k

> MINIMUM NUMBER OF STEAM GENERATORS TO BE INSPECTED DURING INSERVICE INSPECTION C

Z R

ro Preservice inspection No Yes No. of Steam Generstors per Unit Three Three First inservice inspection All One a Second & Subsequent inservice Inspections One 1 One2 R

t Table Notation:

1. The inservice inspection may be limited to one steam generator on a rotating schedule encompassing 3 N % of the tubes (where N is the number of steam generators in the plant)if the results of the first or previous inspections indicate that all steam generators are performing in a like manner. Note that under some circumstances, the operating conditions in one or more steam generators may be found to be more severe than those in other steam generators. Under such circumstances the sample sequence shall be modified to inspect the most servere conditions.

2. Each of the other two steam generators not inspected during the first inservice inspection shall be inspected during the second and third inspections. The fourth and subsequent inspections shall follow the instructions described in 1 above.

• e f ' e e

ATTACHMENT 3 SIGNIFICANT HAZARDS CONSIDERATION l

l VIRGINIA ELECTRIC AND POWER COMPANY l

I

Significant Hazards Consideration Steam Generator Inspection Scope Reduction North Anna Power Station Units 1 and 2 This proposed change to the North Anna Power Station Units 1 and 2 Technical Specifications has been evaluated against the criteria described in 10 CFR 50.92 and it has been determined that this proposed amendment to the operating license involves no significant hazards consideration.

The proposed change is to reduce from two to one the minimum number of steam generators required to be opened for inspection during the first refueling outage following a steam generator replacement. Technical Specifications surveillance requirements 4.4.5.0 through 4.4.5.5 for inspection of the steam generator tubes ensure that the structural integrity of this portion of the Reactor Coolant System will be maintained. Accordingly, the purpose of Technical Specification 4.4.5.1 is to require periodic sample inspections of steam generator tubes. The initial inspection after steam generator replacement combined with the subsequent inservice inspections serve to provide reasonable assurance of detection of structural degradation of the tubes. The proposed Technical Specifications change does not affect or change this basis. However, the requirement that two steam generators be opened and inspected during the first refueling outage after steam generator replacement is considered unnecessary.

The North Anna Unit 1 steam generators were replaced during the first quarter of 1993. Likewise, preparations are being made for replacement of the North Anna Unit 2 steam generators. The general purpose of steam generator replacement is to restore the integrity of the steam generator tubes to a level equivalent to new steam generators. In reality, replacement steam generator components incorporate a large number of design improvements which reflect the " state-of-the-art" technology that currently exists for steam generator design. These design improvements are intended to improve the maintainability and reliability of the repaired steam generators.

The replacement steam generator components for North Anna have been or are being manufactured using current codes and manufacturing techniques without compromising the requirements of the original code thus reflecting current technology in the areas of design, fabrication, and materials. Design changes and enhancements made to replacement steam generator components address the operating experience of the original steam generators and enhance the overall reliability and maintainability of the repaired steam generators. These enhancements are incorporated as not to adversely affect the mechanical or thermal-hydraulic performance of the repaired steam generators. Thus, the replacement steam generators are considered superior to the original steam generators in terms of design and materials.

The proposed change to the Technical Specifications does not involve modifications to any of the existing equipment or affect the operation of any existing systems. The

~

n Page 2 of 2 reactor coolant system reliability and operation are unchanged and, therefore, remain in accordance with the descriptions found in the UFSAR.

The proposed Technical Specifications change does not affect or change any limiting conditions for operation (LCO) or any other surveillance requirements in the Technical Specifications and the Basis for the surveillance requirement remains unchanged. An inspection of the minimum required number.of tubes will still be performed prior to returning the steam generators into service. Although the proposed change reduces the number of steam generators required to be opened for inspection, the minimum number of tubes required to be examined during the inspection is not being changed.

Thus, the inspected tube population size has not changed.

Approval of this change request will also reduce radiation exposure of those personnel involved in opening and closing the steam generator manways and setting up the tube inspection equipment.

Conclusions We have evaluated the proposed change against the critsda described in 10 CFR 50.92 and concluded that the proposed Technical Specifications change does not.

pose a significant hazards consideration.

The proposed Technical Specifications change does not affect the assumptions, design parameters, or results of any UFSAR accident analysis and the proposed amendment does not add or modify any existing equipment. Therefore, the proposed Technical Specifications change would not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed change to the Technical Specifications does not involve modifications to any of the existing equipment or affect the operation of any existing systems. The absence of any hardware or software changes means that the accident initiators remain unaffected, so no unique accident possibility is created.

Therefore, the proposed Technical Specifications change would not create the possibility of a new or different kind of accident from any accident previously evaluated.

Although the change allows the rescheduling of-the steam generator tube inspections, the proposed amendment continues to ensure that the tube inspection sampling will be performed. Therefore, the operability of the steam generators will continue to be verified by the periodic inservice inspections. Since equipment reliability will be maintained, the proposed Technical Specifications change will not involve a significant reduction in a margin of safety.