ML17256A513
| ML17256A513 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 02/23/1983 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Maier J ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| LSO5-83-02-042, LSO5-83-2-42, NUDOCS 8302280406 | |
| Download: ML17256A513 (10) | |
Text
February 23, 1983 Docket Ho. 50-244 LS05-83-02-042 Mr. John E. Haier Vice President Electric and Steam Production Rochester Gas and Electric Corporation 89 Ejst Avenue Rochester, New York 14649
, DISTRIBUTION NRC PDR
'ocal PDR ORB Reading NSIC DCrutchfield HSmith GDick OELD ELJordan JMTaylor ACRS (10)
SEPB EReeves RWright
Dear fear. Maier:
SUBJECT:
COMPLETION OF VALVE OPERABILITY REVIEWS FOR LARGE PRATT BUTTERFLY VALVES USED FOR PURGE LOR VENT OF CONTAINMENTS R. E.
GINNA NUCLEAR POWER PLANT In our letter of November 29, 1978 we identified the generic concerns of purging and venting of containment to all operating reactor licensees and requested your response to these concerns.
Our review of your response was interrupted by the TMI accident and its demands on staff resources.
Consequently, an Interim Position on containment purging and venting was transmitted to you by letter dated October 23, 1979.
You viere requested to implement short-term corrective actions to remain in effect pending completion of our longer term review of your response to our November 29, 1978 letter.
One of the remaining interim corrective actions (and the subject of this letter) still in place while our longer term review is being completed is to:
RHaintain the containment purge and vent isolation valves closed whenever the reactor is not in the cold shutdown or refueling mode until such time as you can show that:
a.
All isolation valves greater than 3" nominal diameter used
, for containment purge and venting operations are operable under the most severe design basis accident flow condition ngtg/
loading and can close w'ithin the time limit stated in your Technical Specifications, design criteria or operating Qalf d6I+~( )
procedures.
The operability of butterfly valves may, on an interim basis, be demonstrated by limiting the valve to be no more than 30o to 50o open (90 being fu'll open).
The maximum opening
~ shall be determined in consultation with the valve supplier."
The valve opening must be such that the ci it' d that the v
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Ilr. John E. Ilaier February 23, 1983 Your letter of June 16, 1981 provided your commitment to operate in conformance with this Interim Position pending completion of our long-term review of valve operability.
However, recent information concerning the operability of large-diameter Pratt butterfly valves (of the generic family R1A or NR1A} in the event of a DBA-LOCA has raised concern whether your justification for oper-ability provided the requ'ired assurance that these.valves will close.
Enclosure 1 provides the background information and the bases for our concern.
Therefore, pursuant to 10 CFR 50.54(f}, you are requested to inform us in writing within 15 days of'eceipt of this letter:
1.
Your assessment of the operability of your large-diameter Pratt purge and vent valves in light of,'he concerns outlined in Enclosure 1,
and 2.
Whether or not you intend to maintain the purge and vent; valves sealed closedin accordance with Standard Review Plan Section 6.2.4, II.6.f and to verify them to be closed every 31 days when-ever the reactor is not in the cold shutdown or refueling mode until such time as you submit acceptable information that demon-strates that your large-diameter Pratt purge/vent valves will operate in the event of a DBA-LOCA.
This;.information will enable the Commission to determine whether or oot further action should be taken to modify, suspend, or revoke your license.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respon,dentsq ther'efore, OMB clearance is not required under P.L.96-511.
Sincerely, Original signed by/
Enclosure:
As stated Dennis H. Crutchfield, Chief Operating Reactors Branch 85 Division of Licensing cc w/enclosure:
See next page
- Please see previous concurrence page.
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8r. John E. Haier Your letter of June 16, 19&1 provided your commitment to operate in conformance with this Interim Posittion pending completion of our long-term reviewoof valve operability.
However, recent information concerning the operability of large-diameter Pratt butterfly valves (of the generic family /RlA or NR1A) in the event of a DBA-LOCA h'as'aised concern whether your inter im position provides the required assurance that these valves will close.
The enclosure provides background information and the bases for our concern.
Therefore, pursuant to 10 CFR 50.54(f), you are requested to inform us in writing within 15 days of receipt of this letter:
l.
Your assessment of the operability of your large-diameter Pratt purge and vent valves in light of the concerns outlined in Enclosure 1,
and 2.
Whether or not you intent to "maintain the purge and vent valves sealed closed in accordance with Standard Review Plan Section 6.2.4, II.6.f and to verify them to be closed every 31 days when-ever the reactor is not in the cold shutdown or refueling mode until such time as you submit acceptable information that demon-strates that your large-diameter Pratt purge/vent valves will operate in the event of a DBA-LOCA.
This information will enable the Commission to determine whether or not further action should be taken to modify, suspend, or revoke your license.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; (therefore, ONB clearance is not required
,'under P.L.96-511.
Sincerely,
Enclosure:
As stated Dennis N, Crutchfield, Chief Operating Reactors Branch 05 Division of Licensing cc w/enclosure:
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February 23, 1983
.CC Harry H. Voigt, Esquire
- LeBoeuf, Lamb, Leiby and t1acRae 1333 Hew Hampshire
- Avenue, H.
W.
Suite 1100 Washington, D. C.
20036 Hr. Michael Slade 12 Trailwood Circle Rochester, New York 14618 Ezra Bialik Assistant Attorney General Environmental Protection Bureau New York State Department of Law '
World Trade Center Hew York, Hew York 10047 U. S. Environmental Protection Agency Region II-Office ATTN:
Regional Radiation Representative 26 Federal Plaza Hew York, New York 10007 Herbert Grossman, Esq.,
Chairman Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Ronald C. Haynes, Regional Administrator Nuclear Regulatory Commission, Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Resident Inspector R. E. Ginna Plant c/o U. S.
NRC 1503 Lake Road
. Ontario, Hew York 14519 Director, Bureau of Huclear Opera tions State of Hew York Energy Office Agency Buildi'ng 2 Empi're State Plaza
. Albany,:New York 12223
- Supervisor of the Town of Ontario 107 Ridge Road West
- Ontario, Hew York 14519 Dr. Emmeth A. Luebke
'tomic Safety and Licensing Board
'U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Dr. Richard F. Cole Atomi'c Safety and Licensing Board U. S. Huclear Regulatory Commission Washington, D. C.
20555
rq.
ENCLOSURE Sack round On August 3, 1982, the evaluation was completed for the 48 inch Pratt butterfly purge valves at Three Wile Island 1 (THI-l)..The qualifica-tion on these valves was found to be insufficient to demonstrate th ability of these valves to close in the event of a LOCA accident.
The major reason for this finding was the determination that the shaft stress would exceed allowable stress when experiencing worst case LOCA torque loads.
P A number of operating plants have Pratt butterfly valves of the sane
'eneric family (R1A or NRlA) and approximate size as the 48 inch RlA butterfly valves at Three Hile Island 1.
Some of these plants have agreed to maintain these valves sealed closed in operating modes above cold shutdown.
A larger number of plants,
- however, do operate these valves for some period of time during operating
- modes, opening the valve to.a limited maximum opening.
The limitation on maximum valve opening has been determined by the licensees in consultation with the valve vendors in accordance with the Staff Interim Position of October 23, 1979.
The basis for this positionwas that for most butterfly valves the highest torque lo'ads under"flow would occur at the higher angles of opening.
Sub-sequent testing has revealed that for some valve installations. downstream of an elbow the higher torques may be experienced at smaller angles of opening but for the large majority of valve installations the higher torque at higher angles is valid.
For most of the butterfly valves used for purging and venting operations a maximum opening limitation of 50 degrees has produced sufficient con-fidence in the valve's ability to close in the event of a LOCA to allow continued use of these valves while qualification was progressing.
In June
- 1981, however, Henry Pratt Valves began to inform utilities operating with 48 inch ~and larger R1A and NR1A model valves that addi-tional restrictions might be required for these valves in order to assure the ability of these valves to close under LOCA loads.
Aqcord-ing to Pr'att analy'ses, the valve restrictions auld be n aaximum opening of 30 degrees to 55 degrees, depending on the individual valve or operator.
Since that time, a number of qualification reports for these valves have been submitted for HRC staff review.
The majority 'df these reports have been performed for valves closing from the full open (90 degrees) position.
These analyses have sho~n the valves to be overstressed for this angle of opening.
Pratt has recommended smaller maximum angles of opening for:.
these valves but no analysis has been done to show tQ acceptability of operating the valves at the lower angles of opening.
Two of the licensees'ave submitted reports calculating valve and operator stresses at the lower angles of opening.
These reports were the Turkey Point 3 and 4 report submitted September 17, 1982 by Florida Power and Light (FPEL) and the I
2 Three Nile Island (THI-1) report submitted by General Public Utilities (GPU).
As previously stated, the THI-1 report was evaluated on August 3, 1982 and found insufficient to qualify the va)ves to close aaainst LOCA loads.
C The Turkey Point 3 and 4 report was for 48 inch and S4 inch Pratt RlA butter fly valves. 'hese valves were to be blocked to 35 degrees and 30 degrees respectively.
The peak containment pressure was not used in qualifying these valves but rather a percentage of that pressure by taking credit for the fact that these valves would begin to close before the containment would reach its peak pressure.
Enveloping static seismic loads of gx = 3, gy = 3 and gz = 4 were used in analyzing the 48.inch valve but actual required seismic loads of gx = l. 5, gy = 1.5 and gz = 1.15 were used in analyzing the 54 inch valve.
The calculated shaft stresses for the Turkey Point 48 inch and 54 inch valves were 27,861 psi and 26,534 psi respectively.
The analysis used a shaft stress allowable of 30,000 psi. 'This value was based on the ASHE allowable'of 1.5 Sm for pressure retaining code parts.
Effectively, 30,000 psi would be a minimum yield strength. 't this point a small amount of permanent-deformation would be experienced.
The calculated values are 93 percent and 88 percent of this yield point leavihg small
. margins.
In addition, the values calculated were determined on the basis of strai,qht l.ine aoproach flow.
'The actual installationc ne these valves have elbows and bends upstream which would'>stort the flow profile to these valves and change the torques experienced by
~
these valves.
Tests performed on other model valves have shown-the-effect of upstream elbows as increasing the torque by as much as 100 percent.
As no information has been submitted to date on the effects of upstream elbows on this model valve, it is uncertain what the magni-tude of the increase on torque would be on this valve.
The small margins remaining for the shaft stress for these valves is inadequate to cover the concern of upstream elbows.
Consequently, the qualifica-tion submitted for the Turkey Point 3 and 4 valves is insufficient to demonstrate the ability of these valves to close against LOCA loads.
Although there.are some design differences in the RlA series of butter,-
fly'valves installed in purge and vent systems of operating nuclear
- plants, the inadequacy of the analysis submitted to qualify these valves to'close, in conjunction with the fact that the analyses submitted for the THI-1 and Turkey Point 3 and 4 were for the lowest angles of open-ing, indicates that the Interim Position of October 23, 1979 is insuf-ficient to provide adequate assur ance that the RlA series Pratt butter-:
fly valves used for purging and venting in nuclear pla'nts will close in the event of a LOCA.
Ph t
a.