ML19319C974
| ML19319C974 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear, Crystal River, Midland, Crane  |
| Issue date: | 12/21/1976 |
| From: | Rodgers J FLORIDA POWER CORP. |
| To: | |
| Shared Package | |
| ML19319C975 | List: |
| References | |
| NUDOCS 8003040908 | |
| Download: ML19319C974 (3) | |
Text
__ - - - _ _ _ _ _ - _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
E F1IE,00PI
.P..o..w..e..r.
December 21, 1976 Mr. Norman C. Moseley, Director U. S. Nuclear' Regulatory C6 mission Directorate of Regulatory Operations Region II, Suite 818 230 Peachtree Street, N. W.
Atlanta, Georgia 30303
Subject:
50-302
Dear Mr. Moseley:
Ws have been advised by Babcock 5 Wilcox Coc:pany that a deficiency has been noted within their Nuclear Power Generaticrt Group that, in their opinion, ccustitutes a significant deficiency as defined by 10CFR50.05(e).
The following is a report that cescribes the picblem, the corrective action taken and the basis for the determination that the deficiency meets the 50.55(e) criteria.
REPmT ON INSTALI.ATIm 0F SNUBBERS OF REACIm C001AVT PRESSURE 1TANSMITIERS This report has been prepared pursuant to 10CFR50.55(e) on Significant Deficiencies and documents the investigation of the installation of snubbers on the Reactor Coolant (RC) pressure transmitters at Florida Power Corpora-tion's Crystal River 3 thit.
IDENTIFICATION OF PROBIBf During the course of a review of transmitter snubbing techniques and response times, it was discovered that snubbers had been installed on the Reactor Coolant pressure transmitters. (Snubbers are devices used to dampen out small, undesirable pulsations in transmitter sensing lines.) The problem was simultaneously and independently discovered during an unrelated check of the Non Nuclear Instrurentaticn scope of supply for the Crystal River 3 thit. The RC pressure signal from the pressure transmitter is an input to the Reactor Protection System (RPS) and acts to trip the reactor on either high or lw pressure signals. The RC pressure signal is also conpared to reactor outlet temperature and a reactor tnp signal is produced when the pressure-temperature cornbination is outside the specified operating envelope.
General Office saoi rhdyenin suosi soum. P o som toz. st Pewsowa. monoa 33733. ais-ess-sisi 8003040 9 N
i l
-i Mr. Norman C. Mosel..
Page December 21, 1976 Upper and icwer limits m RC pressure signals are also used to initiate opera-ticn of the high and low pressure injecticn subsystems of the Engineered Safeguartis Actuaticn System (ESFAS).
Inclusion of the snubbers, which are essentially flow restricticms installed upstream of the pressure transmitter in the line connecting the transmitter to the reactor coolant system, was not assumed in the response time used in the analysis for actuation of the RPS and the ESAS. The increase in respcmse time due to the p msence of the snubbers is considered to result in an unaccept-able delay in the pressure signal to the RPS and ESAS and to invalidate much of the safety analysis cceprising Chapter 14 of the Crystal River 3 FSAR.
It appears that these snubbers were inadvertently provided by the vendor. The applicable procurement specificaticn, Spec. No. 1048/0569, Non Nuclear Instrumentaticn, incorporates the following wording relative to snubbers.
" Snubbers shall be supplied where deemed necessary by the vendor." However, in the course of supplying instrunentation for other B5W nuclear plants prior to Crystal River 3, the vendor gave evidence that he understood that snubbers were not permissible for the pressure transmitters, and he did not, in fact, provide them on the other jobs.
The fact that snubbers were being provided for installation with the pressure transmitters on the Crystal River 3 plant was indicated by the listing of these snubbers in the Instruction Book for the Integrated Control and Non Nuclear Instrunentation Systems, Volume 1A, which was supplied by the vendor. This Instruction Book had been reviewed by B5W, but the listing of the snubbers had apparently been overlooked.
CCRRECTIVE ACTIN It has been determined that Crystal River 3 is the only B5W plant (operating or under constructicn) where snubbers were installed in the RC pressure sense line.
A field change order has been issued to remove these snubbers.
To prevent re-occurrence of this problem on transmitters for other plants that have not yet been shipped, the pressure transmitter supplier had been advised that sndbers or other devices that degrade the specified time constant are not to be provided, and B5W engineering perscrmel responsible for the review of instrumentation documentatic-t have been directed to assure that time ccustant requirements in the procurement specification are not deviated from on current and future ccntracts.
CWCLUSION Inclusica of these snubbers is considered to be a Significant Deficiency as de-fined by 10CFR50.55(e) because "the safety of the plant could have been adversely affected" had the snubbers not been removed; (for example, failure to trip the reactor on a low pressure signal could result in fuel rod claMMg damage, and failure to trip the reacter on a high pressure signal could result in reactor coolant pressure boundary damage.) In additicn, the problem " represents a break-dcwn in a porticn of the quality assurance progra::t' in that review of the Instruction Manuals did not result in detection of the presence of the snsbers.
Mr. Norman C. Mose16, Page December 21, 1976 The problem also " represents a significant deficiency in final design approved and released for cmstructicut" in that the design of the RC pressure sensing and transmitting elements of the RPS and ESAS "do not conform to the criteria and bases stated in the safety analysis report" (i.e., the response times used in the FSAR safety analyses).
The necessary corrective acticn in accordance with a B6W Field Qiange Request has been ccmpleted. From the standpoint of Florida Power Corporation, its only participation in the entire activity was the removal of the subject snubbers.
Qt the basis of the BSW doctment and FPC's removal of the snubbers, we censider this stbject to be closed.
If you have any further questions, please advise us.
Very truly > curs, J. T. Rodgers A=sistant Vice President JTR/pb cc: Director, Inspecticn and Enforcement U.S. Ntriear Regulatory Comissicn Washington, D.C.
J. Alberdi i
l i
i l
l
_