ML20134K895
| ML20134K895 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 08/26/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20134K888 | List: |
| References | |
| NUDOCS 8508300496 | |
| Download: ML20134K895 (3) | |
Text
_
8 UNITED STATES 8
k NUCLEAR REGULATORY COMMISSION g
j WASHINGTON, D. C. 20555
%*****j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 44 TO FACILITY OPERATING LICENSE NPF-12 SOUTH CAROLINA ELECTRIC & GAS COMPANY SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUMMER NUCLEAR STATION, UNIT 1 4
I.
INTRODUCTION By letter dated April 9, 1985, South Carolina Electric & Gas Company requested an amendment to the V. C. Summer Nuclear Station Technical Specifications. The amendment would delete Technical Specification 3/4.5.4,
" Boron Injection System," modify bases section B 3/4.5.5, " Refueling Water Storage Tank," and incorporate the necessary administrative changes to the index and page numbering that result from the Technical Specification dele-tion. These changes will allow for the removal of the baron injection tank (BIT) and other piping and components related to BIT operation. Additional information related to this request was submitted by letters dated May 20 and June 20, 1985.
II.
EVALUATION The BIT was originally incorporated into the plant design to meet the criteria of the Standard Review Plan, NUREG-0800, Chapter 15.1.5, " Steam System Piping Failures Inside and Outside Containment." The BIT was installed to provide a reservoir of highly concentrated borated water that would be swept into the reactor coolant system by the safety injection system. The injection of this concentrated boric acid was relied on in the analyses of the steam line break to limit the peak power during the post cooldown return to power.
Historically, the BIT, which contains a relatively small volume of highly borated water, has been a source of operation and maintenance problems at the V. C. Summer Nuclear Station. The heat tracing elements have been difficult to maintain operable and frequent crystallization of the boron in the sampling lines requires additional effort be expended to obtain required samples. Because of those problems, and because improved analysis methods now show that BITS are. rot needed to provide acceptable mitigation of steam line break events, the licensee submitted a request for approval to hydraulically remove the BIT, the heat tracing elements, and other piping and components related to BIT operation.
The licensee proposed to hydraulically remove the BIT from the safety injection system by cutting and capping the BIT inlet and outlet piping, then installing new piping around the BIT. A pipe break and whip analysis was performed for this piping which demonstrates that the surrounding o
8508300496 850826 DR ADOCM 05000395 i
p PH
2-equipment required to safely shutdown the plant is not compromised. Also, the modifications to the system were taken into account in the piping and support load calculations.
With regard to the proposed removal of the heat tracing elements and their corresponding Technical Specification (TS) sections, reduction of boron concentration to zero ppm would eliminate the need for TS sections con-cerning the BIT and associated surveillance including heat tracing.
The proposed hydraulic removal of the BIT and installation of bypass piping was accompanied by a reanalysis of the rupture of the Main Steam line. All analyses were performed utilizing end of life core conditions, minimum safety injection flow, and the highest worth control rod fully withdrawn from the core.
In addition, the BIT was assumed to be installed in the flow path and filled with water containing zero ppm boric acid.
In the evaluation of the " Major Rupture of a Main Steam line," two analyses were done, one with offsite power available and one without offsite power.
The analysis assuming offsite power availability was the bounding event because of the greater heat transfer available with the reactor coolant pumps in operation. The hot, zero power condition, and a 1.4 ft2 double ended rupture (which is the limiting steam line break as a result of the steam generator integral flow restrictor) were assumed. The analyses showed return to criticality with power levels remaining below 15%.
Removal of the BIT was determined not to decrease the departure from nucleate boiling ratio (DNBR) below the minimum DNBR of 1.3.
The analytical methodologies i.e., use of LOFTRAN (WCAP 7907, April 1984), for evaluating the accident have been reviewed and approved by the staff.
With the hydraulic removal of the Baron Injection Tank, heat tracing elements and other piping and components related to BIT operation, core analysis evaluation demonstrated that the departure from nucleate boiling ratto (DNBR) remained above the minimum DNBR of 1.3 for the steam line break accident and therefore the acceptance criteria are still satisfied.
The analyses showed a return to power with power levels remaining below 15%. The analyses demonstrated that the refueling water storage tank is capable of supplying negative reactivity to the core to counteract any positive increase in reactivity resulting from a reactor coolant system cooldown following a main steam line break.
These results demonstrate compliance with the criteria of Section 15.1.5 of the Standard Review Plan " Steam System Piping Failure Inside and Outside of Containment (PWR)."
Based on our review of the applicant's analyses, we find the proposed systems modifications and Technical Specification changes acceptable.
A g^
m
3-III.
ENVIRONMENTAL CONSIDERATION This amendment involves a change in the installation of a facility component located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public coment on such finding. Accord-ingly, this amendment meets the eli set forth in 10 CFR Sec 51.22(c)(9)gibility criteria for categorical exclusion Pursuant to 10 CFR 51.22(b) no environ-mental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
IV.
CONCLUSION The Commission made a proposed determination that the amendment involves no significant hazards consideration which was published in the Federal Register (50 FR 29015) on July 17, 1985, and consulted with the state of South Carolina.
No public comments were received, and the state of South Carolina did not have any comments.
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Comission's regula-tions, and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
Jon B. Hopkins, licensing Branch No. 4, DL Concepecion Balatbat, Reactor Systems Branch, DSI Dated: August 26, 1985
+
9 7
g
August 26, 1985 AMENDMENT NO. 44 TO FACILITY DISTRIBUTI OPERATING LICENSE N0. NPF I2 h ON'.
- yfrgf1 C'
' Docket No. 50-395 I
NRC PDR local POR NSIC PRC System LB #4 r/f J. Mcpkins M. Duncan E. Adensam Attorney OELD R. Ofggs,, ADM T. Barnhart E. l. Jordan,(4)
DEQA:I&E L. Harmon J. Partlow. I&E B. Grimes M. Virgfifo C. Balatbat, RSB i
i
\\
\\
i
\\
i
\\
\\
i
\\
l t
1 1
k
\\
wa:a cap.t g ; ifiel E7
'%w,%.,w
August 26, 1985 AMENDMENT NO. 44 TO FACILITY OPERATING LICENSE NO. NPF Virgil C. Suniner Unit 1 DISTRIBUTION:
/
" Docket No. 50-395 NRC POR local PDR NSIC PRC System LB #4 r/f J. Hopkins M. Duncan E. Adensam Attorney, OELD R. Diggs, ADM T. Barnhart (4)
E. L. Jordan, DEQA:I&E
- l. Hannon, I&E J. Partlow B. Grimes M. Virgilio C. Balatbat, RSB I
OWsD1
- . FIG"i:D " fft~ :s l
/
/bgsned u u..
t M mm ma - w M.
w.-.
w.
e
--