ML19345D511
| ML19345D511 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/26/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-800-313-000 NCR-2397, NUDOCS 8012150257 | |
| Download: ML19345D511 (3) | |
Text
-
~~.
' PART 21 IDENTIFICATION NO. T5D-313-N CUPAW RVE.NI 4 Chr4 DATE 0: LETIER. uht,h*o D00(ET NO. N-329 9
w!
aa DATE DISTRIBUTED nhtro p.m.
ORIGIIML REPORT1 StPPLB7ARY l
.,l
}
DISTRIBUTION:
%p:
n REACTOR (R) 1 REL CYCE &
SAEC4RRDS9S)}
IEE O IE FILES IEFILES IEFILES AD/SG fn'r t.1.5 4 7;I AD/ FREI AD/RDI REGIGG I,II.,III,kV,V REGIONSI.,II,III,IV,V REGIGG I,II,III,IV,V VSO3R BR. R-IV V$ DOR BR. R-IV VSO3R BR. R-IV LO B / IPA FIG 5715 ff'SS/F06 SS-396
.NRR/03L AEDD FIG 7602 LDEB / FPA FIG 5715 ftBS / SG SS-881 IRR/ DOE AEDD FIG 7602 LDEB/FPA FIG 5715 NRR/DSI AStBP E/R I450 AEOD FIG 7602 tR W T SAo/SP ITE-7210A ASLBP E/W 450 IRR/D3L CEhTRALFILES 016 CENTRALFILES 016 ASLBP E/W 450 CBHPAL FIES ( GRON)
CB1 TRAL FILES (GR30 CBiTRAL FILES 016 PDR CBHPAL FILES SS-396 l
CERRAL FILES (GRON)
LPDR PDR PDR TEPA iPDR l
LPDa a
i ACTION:
l PRELIMINARY EVALUATION OF THE' ATTACHED REPORT ItOICATES LEAD RESPONSIBILITY FdR FOLLCWJP AS SFOhN BELOW:
l IE f NRR[
IfSS2 OEER I
l
?
tt.S L
Pa', 8/1/83 257 we 8012150
- : - 4... +.
.c
'z
~TENNESSE VALLEY AUTHORITY g
CH ATTANOOC-A. TENN ESSEE s74ot
=
t,,
1400 Chestnut Streat Towar II Neve=ber 26, 1980
/
%-set, Mr. James P. O'Reilly,Jitector Office of InspecticVand Enforce =ent U.S. Nuclear Ragtilatory Co==ission Recien II d uite 3100 101 Mar)etta St eet Atlap(a, Geors'.s 30303
Dear Mr. O'Reilly:
SE000YAH ' NUCLEAR PLANT UNIT 2 - BROEEN SPRING IN PRESSURIIER SAFETY VALVE -
NCR 2397 - FIHAL REPORT The subject deficiency ms initially reported to NRC-CIE Inspector R. W. Wright on October 29, 1980, in accordance with 10 CFR 50.55(e1.
Enclosed is our fincl report. We consider 10 CFR Part 21 to be applic-
~
able to this deficiency.
If you have any questions, please get in to'ach with D. L. Lambert at r7S 857-2581.
Very truly yours, TE!.5ESSEE VALLEY AUTHORITY L
M. Mills, Manager Nuclear Regulation and Safety Enclosure cc:
Mr. Victor Stello, Director (Enclosure) /
Office of Inspection and Enforcement U.S. Nuclear Regulatory Coc=ission Washington, DC 20555 4
O An Ecual O :crtunit Eme.' oyer
5 ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 -
BROKEN SPRING IN PRESSURIZER SAFETY VALVE NCR 2397 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency A test was performed on unit 2 pressurizer safety valve (2-RV-68-565) before installation.
During the test, relief pressure appeared very erratic. The valve was disassemblad and a broken spring was dis-covered. The valve (and its spring) was supplied by Crosby Valve and Gage Co=pany, Safety I=plications Had the broken spring escaped detection, the pressurizer safety valve could not have functioned properly. The valve was designed to fail in the cicsed position.
The valve spring's failure could have resulted in a blowdown of the RCS.
Although this occurrence is within the design basis event para-meters, the integrity of the pressurizer =ust be maintained in order for the plant to operate safely.
Corrective Action The broken spring was taken out of the valve and replaced with one supplied by Crosby Valvc and Gage Cc=pany. The broken spring was inspected; the failure was apparently caused by quench cracks in the spring =aterial.
There is every indication that the broken spring was an occurrence of low probability.
Crosby asserts that 300 nuclear and hundreds of thousands of nonnuclear valve springs (in noncorrosive environ =ents) have no other reported history of failure. A TVA-sponsored Licensing Infor=ation Service search revealed only one failure in a 3/4-inch Crosby relief valve. There were no known spring failures. Six domestic FYR's have a total of 33 Crosby relief valves which were bought in the same lot as Sequoyah; none of these has experienced spring failure or displayed quench cracking. Unit 2 valve springs are being inspected and preliminary results indicate no aberrations.
The =ishandling of the cetallurgical process which formed the faulty spring could recur; however, exatination and testing procedures have proven suf-ficient to reveal a deficiency of this nature.
TVA will continue to monitor and test valves in the preoperational phase of construction at Sequoyah Nuclear Plant (SNP) unit 2.
As in this case, any defective or unsatisfactory vaives or components will be documented and dealt with as such.
TVA expects to complete inspection and preoperational testing of all similar valve springs at Sequoyah unit 2 by March 1, 1981.
e