ML20024D296
| ML20024D296 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Arkansas Nuclear, Crystal River, Rancho Seco, 05000000, Crane |
| Issue date: | 07/29/1983 |
| From: | Taylor J BABCOCK & WILCOX CO. |
| To: | Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-83-939-000 PT21-83-939, PT21-83-939-000, NUDOCS 8308040473 | |
| Download: ML20024D296 (4) | |
Text
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Utility Power Generation Division Babcock & Wilcox a McDermott company 3315 Old Forest Road P.O. Box 1260 Lynchburg, Virginia 24505-1260 (804) 385-2000 July 29,1983 Mr. Richard C. DeYoung, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
10 CFR 21 Notification
Dear Mr. DeYoung:
In accordance with the reporting requirements of Section 21.21(b)(s) of 10 CFR 21, the following information is submitted:
(1)
Name and address of the individual infoming the Commission:
Mr. J. H. Taylor Manager, Licensing Services The Babcock & Wilcox Company P. O. Box 1260 Lynchburg, VA. 24505 l
(ii)
Identification of the facility or the basic component with the
)
potential safety concern:
(
" Guidelines for Small Breaks for Oconee 1, 2& 3, Three Mile Island 1 &
2, Rancho Seco and Arkansas 1"
B&W Document No.
74-1122501-02 and " Guidelines for Small Breaks for Crystal River Ill" B&W Document No. 74-1123094-02.
(iii)
Identification of the fim supplying the basic component:
The two documents -- B&W Doc. No. 74-1122501-02 and B&W Doc. No.
74-1123094-02 were prepared and issued to the above identified plants by The Babcock & Wilcox Company, Utility Power Generation Division, Old Forest Road, Lynchburg, Virginia.
(iv)
Nature of the safety concern which is created or could be created:
The small break operating guidelines (SB0G) provided to the identi-fied operating plants in the 1980 to early 1981 time frame con-tained guidance on themal shock that could be interpreted to per-mit repressurization under forced flow conditions in the reactor coolant system as long as the technical specification RTNDT limits are not exceeded.
$h 8308040473 830729 fh PDR ADOCK 05000269 s
1 Babcock &Wilcox Mr. Richard D. DeYoung July 29, 1983 Additional knowledge gained since the issue of the SB0G indicates that overcooling events, where the RCS is cooled below 500*F at a rate greater than 100*F/hr, can create significant temperature difference across the reactor vessel wall.
This vessel wall AT could increase the themal stress on the reactor vessel increasing the possibility of gradual flaw propagation eventually resulting in brittle fracture cracking of the vessel.
These original guidelines were aimed primarily at getting the plant into a safe shutdown condition after a small break LOCA event.
While the SB0Gs did touch upon overcooling transients, they did not deal to any great extent with repressurization scenarios.
However, interpretation could be made of a figure and a statement in the guidelines that repressurization and restart was pemissible from either a natural recirculation or forced flow RCS condition regardless of the extent or rate of RCS cooldown.
B&W operator training personnel reported that some plant operators indicated that the figure in the SB0Gs that could be misinterpreted had been included in utility plant emergency operating procedures pennitting the assumption that repressurization without regard to extent or rate of cooldown was permissible from anywhere between the 50*F subcooling margin limit and the Technical Specification NDT limit ignoring the Interim Brittle Fracture Limit.
While use as guidance for repressurization and restart, as described above, may have been beyond the original scope of the small break operating guidelines, the lack of limitations in usage might be interpreted to represent a defect in a delivered product that could have presented a significant safety hazard as defined in 10 CFR 21, i.e.,
propagation of a reactor vessel fl aw.
This could be considered to be the case even though the defect was brought 1
into focus by knowledge gained after the issue of the guidelines.
While it is not clear whether this concern represents an l
actual defect in a safety related basic component delivered l
to a facility subject to regulation under Part 21, it has l
been decided to judge it as such and report it under the requirements of Section 21.23 of 10 CFR 21.
i This concern is limited to the SB0Gs supplied to the B&W i
plants listed in vi below.
. =
Babcock &Wilcox - Mr. Richard C. DeYoung July 29, 1983 (v)
The date on which infomation of such safety concern was obtained:
Mr.
D.
E.
Guilbert, Vice President, Utility Power Generation Division, was infomed of this reportable concern at11:30 A.M.
i on July 28.
, 1983.
(vi)
The number and location of all subject components in use at, sup-plied for, or being supplied for facilities subject to the regula-1 tion:
One small break operating guideline
- document, Doc.
No.
74-1122501-02 was supplied to each of the following plants; Oconee 1, 2 & 3, TMI-1 & 2, Rancho Seco and ANO-1.
One Small Break Operating Guideline Doc. No. 74-1123094-02 document was supplied to Crystal River III.
(vii)
The corrective action which has been, is being or will be taken, name of the individual or organization responsible for the L
action, and the length of time that has been or will be taken to complete the action:
1 B&W has sant site instructions to each of the affected plants ex-plaining the potential misuse of the figure and misinterpretation of the statement in the SBLOCA operating guidelines in question, providing instructions concerning limitations on repressurization i
and restart after a rapid cooldown below 500* and providing a revised SB0G figure that eliminates any possible misinterpretation of pemissible repressurization and restart conditions.
Recently issued Abnomal Transient Operating Guidelines (ATOG) are being reviewed by B&W to determine if the ambiguous figure from the SB0G has been included.
If such is the case, the AT0G
]
documents will be corrected.
a (viii)
Any advice related to the potential safety concern that will be given to purchasers or licensees:
None beyond the recommended site instructions and ATOG review de-scribed above.
A telephone report of this concern was made to J. G. Partlow of the Office of Inspection and Enforcement on July 29. 1983 0 9:30 A.M.
4 1
5
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Babcock &Wilcox Mr. Richard C. DeYoung July 29, 1983 If you have any questions, you may contact T. L. Baldwin of my staff at 804-385-3142.
Yours very truly,
/
&[
ob s
James H. Taylor Manager, Licensing Services l
JHT/11 cc: Mr. R. B. Borsum B&W Bethesda Office Mr. K. S. Canady Duke Power Company Mr. J. M. Griffin Arkansas Power & Light Mr. D. G. Slear GPU Nuclear Corporation Mr. D. G. Raasch Sacramento Municipal Utilities District Mr. F. R. Miller Toledo Edison Company Messrs.
E. M. Good /B. A. Taylor Florida Power Corporation W
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