ML20077Q744

Forwards Comments on NRC Position Discussed During Steam Generator Owners Group 830706 Meeting Re Steam Generator Generic Requirements

ML20077Q744
Person / Time
Site:	Comanche Peak
Issue date:	09/12/1983
From:	Clements B TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
NUDOCS 8309160195
Download: ML20077Q744 (4)

Text

_

TEXAS UTILITIES GENERATING COMIMNY 2001 DRYAN TOWER . DAh% TEXAS 76201 4

"'Tj,,'l;,",,7"'" September 12, 1983 Mr. D. Eisenhut, Director Division of Licensing Office of Nuclear Reactor Regulations Washington, DC 20555

Subject:

Comments on NRC Positions on Steam Generator Generic Requirements

Dear Mr. Eisenhut:

On July 6, 1983 the Utilities Steam Generator Owners Group attended a t

public meeting to discuss the latest position of the NRC staff on Steam Generator Generic Requirements. During that meeting, the NRC Staff presented their current position.

Although we are not a member of the Owners Group, we are attaching for your information our comments on the NRC position presented at the meeting.

Very truly yours, f +

if l

BRC/GSK:cp Attachment

\

8309160195 830912 l PDR ADOCK 05000445 A PM I

COMMENTS ON NRC POSITIONS ON STEAM GENERATOR GENERIC REQUIREMENTS (Items not in numbered sequence have either been dropped as an NRC requirement or staff action is forthcoming.)

1. Prevention and Detection of Loose Parts We concur that both secondary side visual inspections and QA procedures for steam generator (S/G) entry will improve S/G reliability by preventing / removing loose parts prior to system operation.

2. Tube Inservice Inspection 2.1 We are opposed to increasing tube inspection quantity to 100%

following the detection of one (1) defective tube or if 5% of tubes inspected are degraded. This added inspection requirement would increase worker exposure, and extend outage periods while potentially reducing the S/G tube rupture frequency by only 5 to l

20% with a corresponding reduction in the probability of core melt and significant non-core melt releases (estimated not to exceed 4x10-6 per reactor year). Such a small reduction does not merit the added inspection requirements. We belive that the current requirements in the Comanche Peak Steam Electric Station (CPSES) Technical Specifications are stated in terms that are easier to implement and provide adequate protection. The current requirements for CPSES are attached.

2.2 We believe that the inspection of the cold leg side of the S/G tubes, so that the full length of the tubes are addressed, will increase reliability by locating tube degredation in an area previously not required to be inspected. Therefore S/G

reliability will be increased.

2.4 We agree that the maximum interval between inspections of a steam

! generator should be limited to 72 months, and we believe that the

! value-impact conclusions support this requirement.

! 5. Secondary Water Chemistry Program CPSES currently utilizes the EPRI secondary side water chemistry recommendations. This requirement probably has the greatest potential

! positive impact on S/G reliability by reducing corrosion mechanisms.

Since the secondary water chemistry program will be definet in procedures ,

I we see no need that it specifically be listed as a license condition.

I i

---m_w-- .--w -,r------- . .-

3- - - - . , . - . - ..---,,-,,,--m, , - . . . - - - - - - - - , - -

9

-9 Paga 2 4

6. Condenser Inservice Inspection condenser leakage would be quickly determined by Item 5 and eubsequent corrective actions taken. Therefore, we believe that this item is not necessary to be listed as a license condition.

8. Primary to Secondary Leakage Limit As indicated in your value impact conclusions, " steam generator tube rupture during severe transients or accidents have never occurred",

thus the potential benefits of imposing more restrictive Technical Specifications to reduce the probability of S/G tube rupture are questionable. The existing approved Technical Specifications should be considered sufficient.

9. Coolant Iodine Activity Limit We believe that the existing inservice and secondary water chemistry programs in place at the Comanche Peak Steam Electric Station will have the greatest impact on S/G reliability, and in turn will decrease the possibility of a steam generator tube rupture. It is our opinion that prevention of a design basis steam generator tube rupture is significantly more important than placing more restrictive limits on iodine activity in the primary coolant.

11. Safety Injection Signal Reset The Comanche Peak plant has a Safety Injection reset that will allow continued operation of the engineered safety features equipment. It is our opinion that this requirement does provide a benefit.

In summary, we believe that the only requirements that would have a beneficial impact on S/G reliability are requirements 1, 2 (exclusive of 2.1 on the supplemental tube inspections), 5, and 11. However, for these four requirements, the Value/ Impact (cost /benetit) Analysis failed to prove that both the occupational radiation exposure and the hazards to the general public were major factors. Therefore, based on the above comments, we are opposed to any of the items shown (1, 2, 5, 6, 8, 9,11) j becoming licensing requirements.

~ '

i, C-1 <5% of tubes inspected are degraded and none are defective. ,

i. C-2 }.1 but not more than 1% of total tubes inspected are defective or between 5 & 10% of tubes inspected are degraded.

>10% of tubes inspected are degraded or more than 1% of tubes inspected are defective.

C-3 -

TABLE 4.4-2 -

g .

h STEAM GENERATOR TUBE INSPECTION ,

9 en IST SAMPLE INSPECTION 2ND SAMPLE INSPECTION 3RD SAMPLE INSPECTION u

9 x .

Sample Size 1

Result Acjion Required Result Action Required Result Action Required I

c A minimum of C-1 . None N. A. N. A. N. A. N. A.

! 5 S Tubes per i

S. G. .

j, C-2 Plug defective tubes C-1 None N. A. N. A.

and inspect additional Plug defective tubes C-1 None 2S tubes in this S. G. C-2 . and inspect additional Plug defectiva tubes C-2 M 4S tubes in this S. G.

4 Perform act. ion for C-3 C-3 result of first sample Perform action for m C-3 C-3 result of first N. A. N. A.

g sample

• Inspect all tubes in All other O C-3

" this S. G., plug de. S. G.s are None N. A. . .

fective tubes and C-1 inspect 2S tubes in Some S. G.s Perform action for N. A. N. A.

• each other S. G. C-2 but no C-2 result of second -

additional sample m

Prompt notification S. G. are to NRC pursuant C-3  :::o i to specification Additional Inspect all tubes in Q m

6.9.1 S. G. is C-3 each S. G. and plug

' defective tubes.

y Prompt notification N. A. N. A.  :::D to NRC pursuant to specification h

r v3 6.9.1  %

c2 S=3N% Where N is the number of steam generators in the unit, and n is the number or steam generators inspected n during an inspection Q

g l

.