ML20237A868
| ML20237A868 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 02/14/1975 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Feldmann M BOSTON EDISON CO. |
| References | |
| CON-#487-4998 2.206, NUDOCS 8712150323 | |
| Download: ML20237A868 (5) | |
Text
,
(F7rNETNtfMim
- 2 % (2.20 L[ Cf g h o 0 D. & Im L FAC.-..,,,.
[,
. nw DISTRI
.' ION :
G I
KK NRC PDR LShao Local PDR Schan Docket DUdrisi ORB #2 Reading LSIkers l
KRGoll'er UDeBevec NB 14 370 l
Docket ro. 50-293
'8'l NOV -5 A10 :57 TJCartsr eec CE e D I
its- (3) ChE.
0",M,.
DLZiemann 00L nt.
~,a PW0'Connor gpg,,
Eoston t#ison Coripany RMDiggs ATTN:
Fr. Maurice J. Feldmano JRBuchanan, ORNL Vice President TBAbernathy, DTIE Engineering and Operations SVarga 800 Loylston Street ACRS (12)
Boston, Massachusetts 02199 j
Gentlemen Experiences at various BHis plants with bark I Contain: rents have shown that dat-age to the torus structure can occur f rotr. two different phenotaena associated with relief valve operations.
Darnage can result from the
)
force exerted on the structure when, on first opening, relief velves j
discharr,e air and steam into the torus water.
This phenomenon is referred to as steam vent clearing.
Demare also can result from torus vibrations 1
which acconpany extended rellet valve discharpe into the torus vmter or i
the flow from the. drywell during a LOCA if the pool water is at elevated t er ne ra t ure s.
This ef fect is known as the stca. cuenchine vicration ph enomenon.
These pheno:nena are discussed below.
Steam Vent Clearin,r Ehenomenen I
The Fark I torus structure of sone boiline s eter reactor plents was t our.d to be defective following cycles of stece vent clearing into the torus vhen eriecry systen relief valves cpened.
Invertiratien indicated thet rene of these olants ray not have been designed to withstand this phenomecon throurbout the lite of the niant when the torus wcs subjected to o predicteu nunber of relief valve openings.
The Oued Cities ilnit 2 and the trewns terry L' nit 1 torus structures vera eubjected to tests wbcn defects or excessive noise anc vibrations were discovered followine the above phenonenor..
As a rest.lt et these tests, sore modifications to the torus structures were made for these freilities and sone similar facilities.
Because cf tne appcrent trecressive nature of the material f atigue type of failure pheno-senon, we do not believe that there is any irmediate potential hazarJ; aowever, we presently do not
{1) laDO l'Ob$9 "5EaTVent Clearinp Phenomena and Structural hosponse of the BWR Torus (Mark I Containment), General Electric Comp (2)
"1973 Erowns' Ferry Unit 1 Torus Experienec" submitted by the b,j' Ternerne, Vm11mv Anchmeteu en n._
n_ r r_ t _ _
.r n
t y
..r im omen __ t0AB.
3kt0RB._f2
_.__RL
- 0_
- _2, _
sunsau m s.._____..P_g '_Cgnngy,/ tc,.,RLZ,1e,m.a,n_ n,,,,
_______.=
o^r* __..175 -___ _21.6 /_U.........-_2]_/j,M_____.
Form AEC-H8 (Rev. 9 53) AECM 024c B712150323 750214
'*-~'s PDR ADOCK 05000293 P
l Loston tdison Company...
c.c 14,e7a-have the necessary assurance that the entire life it the facilities. (3)the torus structu integrity throurhout 1
)
i!
l' Steam Ouenching Vibration Phenomeren 1
Elevated torus pool temperatures durex extended relief valve operation have beccee of concern in light of oct.2. rences at
,,i as reported to us by the General Electric Company.(4)(5)two European reactors pool temperatures in excess of about hith local torus operation, it was observed that 170F, due to prolonged relief valve ii with moderate to high relief valve flow rates. severe torus structural vibrations occurred vibrations were caused by a steam condensing mode characterized by p CE reported tnat these i
pulsation of the steam jet the relief valve discharge point.
o c l
to continue, at the torus due to material fatigue.the vibrations could have resulted in struc If allowed 1
The probability for this vibration phenomenon from extended relief operation is considered to be valve technical specifications. low in view of operating limits imposed by
[;
- i current l
on torus pool te1,peratures gecerally limit'Ihe existing-technical specifications
'l
(90-95F with a maximum short nornal power operations to term limit of 120-13CF.
have arisen when a relief valve remained open for extendedhowever, occasions in elevated pool temperatures and creating the potenti periods resulting i.
ouenching vibration pheno:nenon.
al for the steam Recues ted Act.i..on.
ji In view of the be initiated.
foregoing considerations, we request that the followinn action 1.
For the Stear. Vent i
Clearing Phenomenon, a program should be developed
!i
(
for our review that is directed toward establishing
}.
interrity of the torus of your riant.
the continuinn in developint your program:You shculd consicer et least i
the followinr.
1
'Ibe need for verification tests.
]
(a)
(b) The need of the torus st ructure,for physiccl codifications to improve capability i' i
U T~' Letter, I. Stuart, CE Company froa W. Lutler, AEC, dated September 121974.
(4) letter, E. C. Case, llSAEC, fror I. F. Stuart, GL Company dated November 7, 1974 (5)
Let t er, E. C. Case, 1)SAEC, from 1. F.
1974.
Stuart, CE Company dated December 20.
OFFICE >
O V
SURNAME)
DATED l
....._........ _...... _......m.................,
Fon 8 Ufev3 53) AECMM40 ft EsToommeren indreo ohics? ins--mi ei f
a t
~ ~
1 I
i O
Boston Edison Company,.
FEB 14 E75 (c) The torus fatigue characteristics when subjected to forces i
resulting from opening of relief valves.
(
(d) The predicted maximum number of relief valve openings,
'I singly and collectively, during plant life.
(e) Surveillance requirement s, including frequency of i
inspections, for verification of torus structural I
integrity.
2.
For the steam quenching vibration phenomenon, operating procedures should be developed, and changes to the Technical Specifications j
i should be proposed to preclude the development of elevated temperatures of the torus pool water and provide for inspection of the torus as appropriate to identify any damage in the event of an extended relief valve operation.
In this effort, consider the results of your review i
required by Regulatory OperationsBulletin 74-14, " EWE Eelief Valve i
Discharge to Suppression Pool", dated November 11, 1974, and the interim recommendations of the General Electric Company to EWh owners (references 4'and 3).
3.
Submit t
a description of your program and your proposed changes to the t
Technical Specifications.
A suggested review schedule with major j
milestones and dates is enclosed for your consideration; if these dates satisfactory, adjustments may be possible af ter discussion are not with us.
If you do not intend to initiate a program for verification of the torus and/or proposed surveillance requirements, we require that you submit appropriate justification.
}
Your submittals are requested in accordance with the proposed s c h ed u le.
Three signed and notarized orisirals and thirty-seven (37) copies ci your subaittals are needed for our review.
Sincerely, Of f I
DenRis L. Ziemann, Chief Operating Reactors Eranch v2 Division of Peactor Licensing l
Enclosure:
Proposed Schedule of Major Activities This request for generic information was approved by GAO under a blanke clearance number B-180225 (R0072); this cc**
See next page clearance expires July 31, 1977.
orricc>
.................l.-_..............
SURNAME)
{ - Form AEC.318 (Rev. 9 53) AECM 0240 DATE>.......--....-_...
ft u 3 novsneunt nmemo omes e,ve-.4se.se-
.-.m le.
N
n FEb 1 cc w/ enclosures:
!!r. Dale G. Stoodley, Counsel Boston Edison Coc:pany 800'Boylston Street Boston, Massachusetts 02199 Mr. J. Edward Howard, Superintendent Nuclear Engineering Department Boston Edison Company 800 Boylston Street Boston, Massachusetts 02199
{
Mr. Grant Baston, Pilgrim Division Head 4
Boston Edison Company RFD #1 Rocky Hill Road 4
Plymouth, Massachusetts 02360 Mr. Winfield M. Sides, Jr.
Quality Assurance Manager 800 Boylston Street Boston, Massachusetts 02199 Anthony Z. Roisman, Esquire Berlin, Roisman and Kessler 1712 N Street, N. W.
Washington, D. C.
20036 Plymouth Public Library North Street i
Plymouth, Massachusetts 02360 Mr. J. E. Larson 1
I Senior Licensing Engineer and Co-ordinator
)
Boston Edison Company RFD #1 Rocky Hill Road Plymouth, Massachusetts 02360
'~2 1
r-
. e
- gem ows w-
_ _ _ _ _ _ _ _ _ _ _ _ _ _.. ~. - - - - - - - - - - - - ' - - - - " ' ' - ' - - - - - - -
i i
r r
a, S J
y ENCLOSURE
. I-
}
SCHEDULE OF MAJOR ACTIVITIES 3
l TORUS STRUCTURE INTEGRITY I
' Activity Date Letter to Licensees February 15, 1975 j
Responses of Licensecs
)
t w/ Proposed Technical Specifications Revising Temperature j
Limits March 31, 1975 l
w/ Proposed Program for Maintaining Integrity of the Torus May 30, 1975 i
Review of Responses and Issuance of Technical Specification Changes on Temperature Limits August 29, 1975 Qucation: to Licen cca Rep,arding Program for Maintaining Integrity of Torus September 26, 1975 Licensee's Response with Proposed Technical Specifications on Surveillance Requirements November 21, 1975 i
i Review of Licensee's Response and Proposed Technical Specifications Surveillance Requirements January 2, 1976
-l Technical Specification Change on Surveillance Requirements Issued February.2, 1976 Expected Completion of Modifications February 2, 1976 i
l i
s.
=
-