ML19290A270
| ML19290A270 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/18/1978 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| GQL-0581, GQL-581, NUDOCS 7910310576 | |
| Download: ML19290A270 (6) | |
Text
M M
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
DISTRIBUTION FOR INCOMING MATERIAL 50-289 REC: REID R W ORG: HERBEIN J G DOCDATE: 04/18/78 NRC METROPOL EDISON DATE RCVD: 04/24/78 COPIES RECEIVED DOCTYPE: LETTER NOTARIZED: NO LTR 1 ENCL 1
SUBJECT:
FORWARDING SUPPORTING INFO TO APPLICANT"S O2/14/78 TECH SPEC PROPOSED CHANGE I
I INFO.
PLANT NAME: THREE MILE ISLAND - UNIT 1 REVIEWER INITIAL:
XJM DISTRIBUTOR INITIAL: (
- DISTRIBUTION OF THIS MATERIAL IS AS FOLLOWS ******************
GENERAL DISTRIBUTION FOR AFTER ISSUANCE OF OPERATING LICENSE.
(DISTRIBUTION CODE AOO1)
FOR ACTION:
BR CHIEF REID**W/7 ENCL INTERNAL:
REG FILE **W/ ENCL )
NRC PDR**W/ ENCL OELD**LTR ONLY i u
--o,_
caut HANAUER**W/ ENCL CHECK **W/ ENCL EISENHUT**W/ ENCL SHAO**W/ ENCL BAER**W/ ENCL BUTLER **W/ ENCL EEB**W/ ENCL J COLLINS **W/ ENCL J.
MCGOUGH**W/ ENCL EXTERNAL:
LPDR'S HARRISBURG, PA**W/ ENCL TIC **W/ ENCL NSIC**W/ ENCL ACRS CAT B**W/16 ENCL 1563 298 DISTRIBUTION:
LTR 40 ENCL 39 CONTROL NBR:
781160157 SIZE: 1P+2P+2P THE END
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791081067$ g
maa son rooansss METROPOLil AN EDISON COMPANY POST OFFICE BOX 542 READING, PENNSYLVANI A 196C3 TELEPHONE 215 - 929-0601 April 13,1978 gal 0581 Director of Nuclear Reactor Regulation 4K Attn:
R. W. Reid, Chief y
Operating Reacters Branch No. k j/ o/
((gu6 'k]/ g r[g g\\
U. S. Nuclear Regulatory Conmissicn 4p Washington, D. C.
20555 U u4 g49,jg7g
Dear Sir:
T Three Mile Island Nuclear Station, Unit 1 (TMI-1) h' / g ijiG'\\
Operating License :To. DPR-50 Docket No. 50-289 Technical Specificatien Change Request No. 71 Ycur letter of February 2h,1978 requested additienal informaticn in order for you to review the subject request. Upcn review of Met-Ed's submittal, it was determined that certain technical justification had been cnitted, be-cause this issue appeared to be generic and had been addressed by several other licensees. Furthermore, Met-Ed incorrectly stated that the reason fcr requesting the change was to meet NEC concerns and requirements.
In view of the above, the attached pages are forwarded in support of Technical Specification Change Request No. 71.
Sincerely, f
,/
=
/
/
J. G. Herbein JGH:RJS:cjg
'/, Vice President-Generation
/
1563 299 ittechme"*
D IOTlJDCET M CDPY r
y lf001)S ll1
c 0531 "hree Mile Island Nuclear Station, Unit 1 (04I-1)
Operating license No. OPE-50 Docket No. 50-289 Technical Specification Change Request No. 71
( Additional Information)
Peasons for Chance Eequest The present TMI-1 Technical Specification 4.16.1.c states, " verifying thrcugh manual actuatien that the valve begins to cpen frc= the full closed position with a force equivalent to 1 (0.15) psid, and is fully open with a force equiv-alent to 1 (0.30) psid." 3&W reviewed the assu=ptions used in the ECCS analysis and determined, "De=cnstration that the vent valves vill be fully cpen when a pressure differential is applied across them that is lever than that cbtained during the LOCA analysis is sufficient to verify that the vent valves are oper-at ional. " 3&W further determined that the required pressure differential necessary to hold the vent valves full open must be shcun to be nc core than 1.0 psid, and that the Tech Spec should read, " verifying through manual actuatien that the valve is full open with a force equivalent to 1 (1.00) psid."
Since these valves are ncrmally exercised by applying a force vertically upward with 5
an exercising tool, B&W calculated a vertical force of 1 00 lbs. to be equiv-alent to a differential pressure of 1 {1.00) psid.
This change deletes the start-to-open criterien, assumes chan~ing the full-open criterion frcn < (0.30) e psid to h
(applied vertically upward) 1 (1.00) psid, and specifies a force of 1 00 lbs.
to verify that the valve is fully open.
Safety Evaluation Justifyinz Chance NRC letter of March 10, 1976, concluded that a vent valve flow penalty need not be taken if reactor internals vent valve surveillance requirements are incer-porated into the Station Technical Specificatiens. The NRC issued Amend:ent No. 25 on March 7,1977, to the TMI-1 Technical Specifications. However, based en experience at other plants, the criterien appeared to be overly censervative and restrictive.
In an atte=pt to rectify the situation, 31W reviewed the as-sumptiens used in the ECCS analysis regarding action of the internals vent valves and determined that:
1.
In the event of a LOCA in the reacter inlet piping, internals vent valves have been designed in crder Oc provide a direct steam relief path frcm the upper plenum to the break. During the ref1 coding phase of a 1CCA transient, steam generated frca ECCS fluid cc=ing into contact with the het cladding vill pressurice the upper plenum, thereby opening the vent valves and alleving steam to flew through them.
The rate of steam relief is calculated using a conserva-tively high flow resistance factor (k-factor) cf h.2 as is discussed in Topical Repcrt BAW-1010h. Derenstration that the vent valves vill be full open when a pressure differential is applied across them that is lower than that obtained during the LOCA analysis is sufficient to verify that the vent valves are operational.
2.
Large break LOCA analysis for 3LW 177 FA plants de=cnstrating the ccepliance of the ECCS systems to 10 CFR 50.h6 has been reported in Topical Repcrt 3AW-10103. During the reflecding phase of the accident, a pressure differential in excess of 1.0 psid was maintained acrcss the vent 7117es throughcut the transient.
Therefore, the required press"-a d'"erential necessary tc hold the vent valves full cpen must be shcun to be nc core than 1.0 psid.
1563 300 GQL 0531 Attached find the force equivalent calculation for a 1.3 psid driving force necessary to hold the vent valves $211-open. As can be seen by this calcu-lation, the value specified in the propcsed Technical Specification ensures that the valves vill be open during the reflocding phase. Also attached, for infernational purposes cnly, find the calculation for derivation cf the force equivalent needed fcr the vent valves to start to open.
As BA'i-10103 takes credit for the valves in the full-open pcsition only and by virtue of the fact a lesser force equivalent is required to start-to-cpen, the requirement for testing of the valves " start-to-open" force is deemed to be unnecessary.
1563 301
GC 0531 Pu nese:
Calculate equivalent vent valve exercise force to " Hold-Cpen" pressure of 1.0 psi.
Analysis:
The valve face =akes an angle of 26 vith the vertical in the cpen positicn. A one (1) psi pressure drop acting over the 15 inch expcsed disc face has a 9 3/3 inch =ccent arm with the hinge.
Mcment = Pressure Drcp X Area X Mctent Arm
=1.0psiXf(15in.) X 9.375 in.
= 1660 in-lbs.
Since the exercising force is a vertical force applied to the exercising pin, its
=ccent ar: is the projected hcriscntal distance cf its radial iccation with respect to the valve hinge.
Fin Radial Locatien is ((h) + (5/8) ) = h.0h8 in.
The angle the pin makes with the horicental when the valve is open is the angle the valve makes with the vertical (26 ) minus the angle of the pin frcs horizontal when the valve is vertical (6):
-1 5/8 Angle = 26o - Tan
- wps g
a
= 17.1 Mcment of th e exercising force:
j M, cree = Force X Fin Radial Location X Cesine Angle
&.4 g
= F X h.0h3 X ces 17.1 260
-1
.625
,o 9= _an
= c.w
= 3.87F Setting the force =ctent equal to the pressure =crent, the equivalent vent valve exercising force is solved:
3.STF = 1660 F = h30 lbs.
1563 302
GQL 0581 Purpcse:
Calculate equivalent vent valve exercising force to " Start-To-Open" pressure.
Analysis :
To simplify part=eterizations, the calculations will be based en 1.0 psi driving pressurf.
For any other " start-te-open" pressure, the equivalent exercise force vill be in direct proportion; i.e., for a 1/2 psi differential pressure, the exercise force is 1/2 the calculated value given belev.
In the " closed" position, the valve hangs 5 from the vertical.
The =ctent ar of the exercising pin when the valve is clcsed is:
5
-1 5/8 o
, = ((h)2 + (g)2 ) cos (Tan
-5 )
u 3
= h.039 in.
The pressure noment of the pressure acting over the lh inch face of a c1csed valve is:
5 o
M = 1.0 X
- (lh) X 9.375 o
= lhh0 in-lbs.
Setting the force and pressure mcments equal:
h.039F = lhh0 F = 360 lbs.
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