ML20041G074
| ML20041G074 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/04/1982 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| TASK-2.B.1, TASK-TM NUDOCS 8203190172 | |
| Download: ML20041G074 (5) | |
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MAR 4 mg (fo_cket F10 NRC PDR L PDR NSIC Docket tio. 50-285 ORB #3 Rdg DEisenhut 4
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RECGIVED Mr. W. C. Jones JHeltemes
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Division Manager, Production PMKreutzer-3 MARI 01982= T4 Operations RAClark
-, g % g [dr 7 Omaha Public Power District ETourigny L".wn w 1623 Harney Street ACRS-10 s
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Omaha, Nebrahka 68102 EMarenos JHannan y
Dear Mr. Jones:
Gray File
SUBJECT:
REACTOR COOLANT SYSTEli VENTS (ITEM II.B.1)
REQUEST FOR ADDITIOilAL INFORMATION We have completed a preliminary review of your submittals dated October 6, 1980, July 1, 1981, September 17, 1981 and December 28, 1981 regarding TMI Action Plan Item II.B.1, RCS High Point Vents. The additional information identified in the attachment is required to complete our review for your facility.
Uc are currently in the process of reviewing the technical merit of the proposed operating guidelines for RCS Vent usage. We recommend that the questions in this area be resolved generically through the Owners Groups.t Specific plant procedures will be reviewed against the approved guidelines as needed in the future, but not necessarily prior to design approval.
Please supply the requested information within 6L days of the date of this letter.
The reporting and/or recordkeeping requirements contained in this letter are approved under OMS clearance #3150-0065 which expires May 31, 1983.
Sincerely, Original signed by Robert A. Clark Robert A. Clark, Chief Operating Reactors Branch (3 Division of Licensing
Enclosure:
Request for Additional Information cc w/ enclosure:
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8203190172 820304 fDRADOCK05000 OFFICIAL RECORD COPY uscro.isei_335,c s
7 Omaha Public Power District cc:
Marilyn T. Shaw, Esq.
~ LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.
Washington, D. C.
20036.
Mr. Jack Jensen Chairman, Washington County Board of Supervisors Blair, Nebraska 68023 U.S. Environmental Protection Agency Region VII ATTN: Regional Radiation Representative 324 East 1ith Street Kansas City, Mis'souri 64106 Mr. Frank Gibson W. Dale Clark Library 215 South 15th Street Omaha, Nebraska 68102 Alan H. Kirshen, Esq.
Fellman, Ramsey & Kirshen 1166 Woodmen Tower Omaha, Nebraska 68102 Mr. Larry Yandel.1 U.S.N.R.C. Resident Inspector P. O. Box 309
- Fort Calhoun, Nebraska 68023 Mr. Charles B. Brinkman Manager - Washington Nuclear Operations 0-E Pcwer. Systems Combustion Engi,neering, Inc.
4853 Cordell Avenue, Suite A-1 Bethesda, Maryland 20014 Recional Administrator Nuclear Rigulatory Commission, Region IV' Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011 e
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REQUEST' FOR ADDITIONAL INFORMATION FOR
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FORT CALHOUN 1 Based on our review of the " Procedural Guidelines for Reactor Coolant 1.
Fort Calhount Unit No.
Gas Vent System for Omaha Public Power District of your RCGVS submittal in response to NUREG'-0737 1"r provided as part i
Item II.B.1, we require the following additional informat on:
Provide operating guidelines on the methods and instrumentation a.
(no direct reactor vessel measurement) used to detect and deter-mine the volume of gases in the reactor coolant system (RCS).
Also describe the indications expected during reactor vessel if non-condensible gases are trapped in the RCS head ventingr Loops.
Supplement section 4.0 (Emergency Plant' Oper'aI4 ens 3't'o describe b.
The mea-measures required before initiation of RCS venting.
sures could include for example, verification of the contain-isolationi starting of att availablb containment air ment and bringing the RCS to steady-state cer.di-mixing systemsr tions with a pre-determined minimum sub-cooling and pressur-izer water level.
ascears from the guidelines that venting is terminated after c.
It However, we believe the predetermined venting time has elapsed.
that venting should be terminated following a significant change in plant parametersi such as rate of pressurizer level and/or pressure variations.
Furthermorer venting should be increases terminated when the pressuricer level cecreases or to a specified level, when reactor coolant sub-cocling decreases below a specified valuer when pressurizer pressure decreases or when the containment hydrogen by a specified incremente Revise the pro-level increases above a specified value.
cedural guidelines to include clear and spec,ific guide, lines for operator termination of reactor vessel head and pressuri:er I
venting.
Figure 19 "RCGVS Accident Response" of the procedural guidelines -
d.
Enclosure Page 1 of 3 O
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s'tates that ~ the charging pump (s) should be placed-into operatien Define:and justify prior to venting the pressurizer "if necessary".
when the charging pump (s) should and should not be used while venting the pressuri:er.
is the NRC position that your guideline on p. 9 concerning the e.
It decision to continue venting the reactor vessel if the containment hydrogen levels approach combustible levels is too absolute and should be revised to state that while this guideline should be the decision must be based on full consider-generally followede ation of all plant conditions ir cluding the status of core cooling Therefore, guidance should and the containment hydrogen le imating the expected change be provided to the operator for e; as a function of of hydrogen concentration -in the cor.tainment vent t'ime.
Provide operating guidelines which in lipu of'.x;nting,will assure f.
liquid or steam will flow through the steam gener-that sufficient ator U-tube region so that decay heat can be effectively removed from the RCS (reference Clarification C.(2)).
path will te flow restricticn orifice provided in each vent 2.
Verify that leakage to less than the capacity of the reactor limit reactor coolant makeup system by providing the pertinent design parameters of coolant i
s and a calculation of the max-
,the reactor coolant system charg ng pumo imum postulated rate of loss of reactor coolant through a RCGVS flow
restriction orifice C ref erence NUREG-0737 Item II.S.1 Clarification A.(4)).
internal missiles and the dynamic effects associated with 3.
Demonstrate that the esiertial Operatier prevent tne costulatec rupture of. piping will nct form a part of the reactor coolant pre-of the portions of the RCGVS that one vent path remains funct'ional>(refer-ssure bouncary (i.e., at least
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ence Appendix A to 10 CFR Part 50, General Design-Criterion 4).
Verify that the following RCGVS failures have been analyzed and found not 4.
for to prevent'the essential! operation of safety-related systems recuired safe reactor shutdown'or mitigation of the consequences of a design basis accident:
are not designed to withstand Seismic failure of RCGVS components that a.
Enclosure Page 2;o'f 3 e,
x.
Postulated' missiles generated by failure of RCGVS' components.-
b.
failures.
Sprays from normally Fluid sprays from RCGVS component c.
unpressurized' portions of the RCGVS that are Seismic Category 1 or 3 and have instrumentatic'n for detection
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and Safety Class 1, 2r of leakage from upstream isolation valves need not be considered.
Demonstrater using engineering drawings and design descriptions as 5.
that the RCGVS vent paths to the containment atmosphere appropriater discharge into areas:
(both direct and via the quench tank rupture disc) air to prevent the accu-That provide good mixing with containment a.
and mutation or occketing of high concentrations of hydrogene systems, and components essential b.
In which any nearby structurese to safe reactor shutdown or mitigation of the consequences of a are capable of withst,a,nding the effects of design basis accident the anticipated mixtures of steami liquid, and noncondensible discharging from the RCGVS (reference'NUREG D737 Ithm II.B.2 Cla-I rification a.(9)).
of NUREG-0737 Item II.B.1 requires operability testing 6.
Clarification A.(11) in accordance with subsection IWV of Section XI of the ASME Code for Although your submittal of July le 1981, committed Category B valves.
to several of the operability testing requirements, other recuirementsi e.g., verificatien of positive valve positien indication and testing of fait safe valve positions were not discussed. Verify that all require-ments of subsection IWV for Category B valves will be met.
Enclosure Page 3 of 3 e
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