ML20235C088
| ML20235C088 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Zimmer |
| Issue date: | 01/11/1979 |
| From: | Duraiswamy S Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML20234A777 | List:
|
| References | |
| FOIA-87-40 NUDOCS 8707090298 | |
| Download: ML20235C088 (25) | |
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l ACRS Members CERTIFIED MINtTTES OF THE ACRS WM. H. ZIMMER NLCLEAR POWER S'IATION, UNIT 1, NOVD'BER 17, 1978, CIfCIN%IT, OHIO j
Attached is a copy of the certified minutes of the subject meetirg. 'lhe i
attachments included with the Working Copy of these minutes, which were issued December 22, 1978, should be attached to this certified copy to conplete your set of minutes. 'the Working Copy should be destroyed.
l i i I
g' i Sam Duraiswany l
Site Analyst
Attachment:
1.
Wm. H. Zimner Minutes
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of Novemer 17, 1978 i
cc: ACRS Technical Staff I. Catton i
S. Ditto W. Lipinski Z. Zudans
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,n 8707090298 870610 NRC F91Ud 318 (9 76) NRCM 0240 A v. s. oovaRNMENT PRINTING OPP PDR FOIA i
THOMAS 87-40 PDR
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WORKING COPY IRTE ISSUED: 1/11/79 y
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-,s MIN (TTES OF THE ACRS SUBC04MITTEE MEE' TIN 3 ON
'I-WM..H.
ZIMMER NUCLEAR POWER STATION, UNIT 1 CINCINNATI, OHIO l
ww a a s a a ddl NOVEMBER 17, 1978 l
W e ACRS Wm. H. Zimmer Nuclear Power Station, Unit 1 Subcommittee held a meeting on November 17, 1978, at the Holiday Inn, 8050 Highway 42, Florence, Kentucky. Notice of this meeting was published on Friday, October 20, 1978, in the Federal Register, Volume 43, Number 204, Wednesday, November 1,1978, Volume 43, Number 212, and Thursday, November 9, 1978, Volume 43, Number 218; copies are included as Attachment A.
A tentative schedule for the meeting is included as Attachment B. A list of meeting attendees is included as Attachment C, and a list of the back-ground documents submitted to the Subcommittee and its consultants is included as Attachment D.
Dr. Richard Savio was the Designated Federal Employee for the meeting.
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INTRODUCTORY STATEMENT BY DIE CHAIRMAN l
Mr. Bender, the Subcommittee Chairman, convened the meeting at 8:30 a.m.,
reviewed briefly the schedule for the meeting, and introduced the other i
Subcommittee member and the ACRS consutlants. He noted that the purpose of this meeting was to review the application of the Cincinnati Gas &
Electric Company (CG&E) for a license to operate the Wm. H. Zimmer Nuclear Power Station, Unit 1.
S e Subcommittee had received neither written statements nor requests for time to make oral statements from the members of the public.
INTRODUCTION AND
SUMMARY
OF ISSUES - MR. I. PELTIER, NRC STAFF Mr. Peltier indicated that Zimmer plant is the first BWR-5 with Mark II containment to be reviewed by 'the NRC Staff for an operating license.
%e MlC Staff had issued the Safety Evaluation Report (SER) on November 2, 1978 for the operating license review of the Zimmer plant. tere are 17 outstanding issues identified in the SER. Amorg tho,se 17, the NRC Staff has reached a psition for the following issues:
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Zimmer November 17, 1978 1.
Dewatering of compacted backfill 2.
Reactor vessel supports 3.
Preservice and inservice inspection programs 4.
Effects of recirculation pump trip in overpressurization analyses 5.
Protection of motor / generator sets - reactor scram system 6.
Physical separation and electrical isolation 7.
Fire protection 8.
Plant and support staffing 9.
Industrial security Mr. Peltier indicated that the following issues need additional information from the applicant so as to enable the NRC Staff to reach a final position:
1.
Design for pool dynamic loads 2.
Seismic qualification of mechanical and electrical equipnent j
3.
Conservatism in transient analyses 1
4.
Iow Pressure Coolant Injection (LPCI) diversion effects on Dnergency Core Cooling System (ECCS) and long term cooling j
5.
Pool dynamic loads and load combinations 6.
Safety related display instrumentation 7.
All other instrumentation required for safety 8.
Preoperational and startup test program i
l Mr. Peltier roted that the NRC Staff has also considered the ACRS generic f
concerns in the evaluation of the Zimmer plant. Several task action plans
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are being underway to resolve the ACRS generic concerns, ar.d the NRC Staff
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intends to provide a status report on the resolution dates of these matters
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in December 1978.
I Dr. Catton raised several questions to be answered either during the course of the meeting or at a near future date:
1.
Indicating that during one of the recent Power Burst Facility (PBF) tests it was found that a fuel pin came l
apart at 240 calories per gram, Dr. Catton asked, 0FFICIAL USE ONLY
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Zimer November 17, 1978 is this an appropriate issue for the Zimer plant, and has it been considered?
2.
What are the provisions to preclude the thermal stress problems, if any, on the collet retainer tube?
3.
How is the fuel bundle lift potential during the blowdown phase of a LOCA eliminated?
4.
Indicating that the downcomers are over 30 feet long and have no lateral restraints, Dr. Catton asked, what would be the dynamic behavior of the downcomer tubes during blowdown?
PRESENTATION BY ' HIE APPLICANT Organization Structure and Construction Schedule - Mr. E. Boraman, CG&E' Mr. Borgman provided a brief review of the organizational structure of the CG&E (Attachment E).
In response to a question from Mr. Bender as to how many of the operating
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personnel have prior nuclear power plant experience, Mr. Schott from CG&E noted that none of the operating staff members has actual boilirg water reactor experience. However, several of them have prior Navy reactor (submarine 4
j and surface ship) experience. Besides, all the licensing Staff have gone i
through the boiling water reactor training course.
With regard to the schedule, Mr. Borgman noted that the projected fuel loading date is expected to be somewhere in the third quarter of 1979.
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Plant Description - Mr. Brinkman, CG&E Mr. Brinkman stated that the Zimmer plant is located on a 632 acre land on a floodplain of the Ohio River in Washington Township of Clermont County, in Southwestern Ohio. W e site is located approximately 24 miles southeast of Cincinnati, Ohio and 1/2 mile north of Moscow, Ohio.
%e Zimmer plant is owned by the Cincinnati Gas & Electric Company, the Dayton Power & Light Company, and the Columbus & Southern Ohio Electric 0FFICIAL USE ONLY j
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Zimmer November 17, 1978 Company. Cincinnati Gas & Electric Company has the prime responsibility for the design and construction of the Zimmer plant.
he Zimmer plant has a nuclear steam supply system which uses a BWR-5 class of boiling water reactor supplled by the General Electric Company. We total capacity of the Zimmer plant is 2436 MWt (839 fWe). Construction permit for the Zimmer plant was received by CG&E in October 1972. %e commercial operation date for the Zimmer plant is expected to be in January 1980.
Mr. Brinkman discussed briefly the general arrangement of the Zimmer plant, indicating the location of the various buildings and essential components associated with the plant (Attachment F, pages 1 ard 2).
In response to a question from Mr. Bender, Mr. Brinkman noted that there has been some icing on the Ohio River over the years. Ibwever,
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in case of ice formation at the Ohio River, provisions are made to I
take suction of the water from the bottom of the river.
- Besides, they also have provisions to melt the ice by pumping warm water.
t Mr. Brinkman provided a brief description of the Mark II containment features (Attachment F, pages 3 and 4).
Se Mark II containment system includes a primary containment structure and a secondary con-tainment building. Se primary containment structure is a vapor suppression system which encloses the reactor vessel, the reactor coolant recirculation loop, and other portions of the nuclear steam supply system.
It consists of a drywell, a suppression chamber, i
a vent system connecting the drywell to the water pool, isolation valves, containment cooling system and other service equipnent. Se primary containment is a reinforced, prestressed concrete structure with a thickness of 6 feet. % e entire containment structure is lined with a 1/4-inch steel liner which is leak tested. %e contain-I ment is designed to withstand 45 psig internal pressure, 2 psig ex-ternal pressure, and a temperature of 34d F in the drywell. A series I
of steel tendons are also used to prestress the containment.
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t Zimmer November 17, 1978 In repsonse to some questions from Mr. Bender, it was noted that CG&E has an inservice inspection program to inspect the tendons at an interval of 1, 3, and 5 years. %e superintendent of the plant is responsible for implementing this program, and written procedures are being prepared to carry out this program.
In response to a question from Dr. Zudans as to how the integrity of the
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concrete is maintained at a temperature of 3400F, Mr. Krishnaswamy from Sargent & Lundy noted that the 3400F is the maximum ternperature during a Ioss of Coolant Accident (LT.A). te rormal operating tempera-ture of the drywell is about 140 F.
In the event of a LOCA, the temperature of the concrete immediately behind the steel liner will be about 1900F for a short period of time. % e average long term tempera-ture increase during a LOCA w111 be about 300F.
t Dr. Plesset wondered how the temperature could drop from 340 F to 190 F
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through a 1/4-inch thick steel liner.
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Mr. Bender suggested that the NRC Staff look into this issue and provide 3
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the necessary information to the ACRS at a near future date.
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In response to a question from Dr. Zudans as to whether the actual temperature distribution experienced during normal operating conditions and during tran-sient conditions has been factored into the design of the floor that connects the suppression pool to the drywell, Mr. Krishnaswamy from Sargent & Lundy noted that the actual increase in temperature of the drywell floor and the
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containment structure has been studied for both the normal operating and transient conditions and also has been considered in the design of the i
containment.
Dr. Catton raised a question regarding the computational procedures used to get bounding temperatures in the concrete and bounding pressures in the drywell. He also asked whether the heat transfer coefficient used between the drywell evnrionment and the steel shell is the same as that used to obtain the pressure in the drywell.
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Since there were no proper personnel to provide an adequate answer to
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Dr. Catton's questions, Mr. Bender suggested that the NRC Staff work j
with the Applicant to' establish what the computational procedures are and submit to the Subcommittee at a near future date.
In response to a question from Mr. Bender concerning the possible bypass paths of the suppression pool, Mr. Brinkman roted that the Iossible bypass areas would be:
4 1.
Cracks in the floor 2.
Isaks adjacent to the downcomer pipes that penetrate the floor 3.
Imaks in the downcomer pipes 4.
Isaks in the vacuum breaker valves which communicate from the drywell to the wetwell.
Mr. Brinkman reviewed the design, construction, and main functions of the I
drywell, suppression pool, primary and secondary containments, spent fuel pool, and refueling pool.
t In response to a question from Mr. Bender regarding the main steam isolation valves, Mr. Brinkman noted that there are two isolation valves, one is located inside and another one is outside of the primary containment, which is consistent with the General Design Criteria.
Ibwever, under, certain conditions, the Zimmer plant took some exceptions to the General i
Design Criteria in locating other containment isolation valves.
1 Mr. Bender asked when and how the Mtc Staff decides the location of the containment isolation valves.
Mr. Peltier noted that he will provide this information at a later date.
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Indicating that the control rod drive tubes are located very close to I
1 the recirculation line, Dr. Catton expressed concern about the vulner-i ability of the control rod drive tubes from a failure of one of the recirculation lines.
Mr. Bender suggested that the NRC Staff look into this issue and provide appropriate information to the ACRS at a near future date.
Training Program - Mr. J. Schott Mr. Schott noted that the main objective of the Zimmer plant training
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program is to develop and maintain an organization to assume the j
responsibilities for operation, maintenance, and technical considera-tion of the plant. Cincinnati Gas & Electric Company has formulated three separate training programs to accomplish this objective:
1.
Initial plant Staff program - This is designed to produce competent trained personnel at all levels
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of the organization. 'Ihe guidelines delineated in ANSI-N18.1 were incorporated into this program as appropriate.
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Requalification program - This program provides continuing training for all plant personnel commensurate with their area of responsibility.
3.
Replacement training program - This program is
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4 designed to supply qualified personnel throughout j
the life of the plant in the event of some turnover or attrition.
'Ihe subprograms incorporated into the above mentioned main training programs are included in Attachment G.
Mr. Schott indicated that several of the plant personnel has been sent to the operating BWR nuclear plants, such as Hatch and Monticello, for observation and training.
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Zimmer November 17, 1978 l
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In response to a question from Mr. Bender regarding notable differences j
in training the personnel for a BWR-5, Mark II plant and for a BWR-4, Mark I plant, Mr. Schott noted that the Zimmer plant training program is some-what different from the generic General Electric trainirq program. A senior operator for the Zimmer plant is usually trained first in a BWR-4, Mark I plant, and then he will be instructed on the unique features of the Zimmer plant so as to enable him to understand the main differences between Mark I and Mark II plants.
He also noted that most of the Zimmer plant Staff are aware of the main differences between Mark I and Mark II plants.
Emergency Plan - Mr. J. Schott Mr. Schott noted that the emergency plan for the Zimmer plant exceeds the minimum requirements of Appendix E to 10 CFR Part 50, and also incorporates the guidelines delineated in Regulatory Guide 1.101, " Emergency Planning j
for Nuclear Power Plants".
I Mr. Schott indicated that appropriate arrangements have,been made for medical, fire, police, transportation, and radiological support services in an emergency situation.
Relationships between the Zimmer plant organization and, State and Federal agencies, and local support services are included in Attachment H.
Mr. Schott reviewed briefly the emergency plan for the Zimmer plant, indicating that it provides a comprehensive plan that includes adequate organization, communication procedures, monitoring information, training, first aid, transportation, assessment, decontamination, and offsite support to adequately cope with and assure that mesures can be and will be taken to protect the health, safety, and property of the public in the event of an emergency.
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Zimmer November 17, 1978 In response to a question from Mr. Berder concerning the fire protection
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program for the Zimmer plant, Mr. Schott noted that they have in-plant f
fire protection group which was trained by the professional fire consul-I tants.
In addition, they have made arrangements with the Washington Township Fire Department which is located in Moscow, Ohio, as the initial offsite response agency that would respond to a fire call.
Washington Township Fire Department will be backed-up by the Richmond City Fire Department.
i In response to another question from Mr. Bender, Mr. Schott noted that the departments with which they have agreements for fire protection are not professional fire-fighting groups; they are volunteer organiza-tions.
I Mr. Bender remarked that it would be advisable to make certain arrangements with some professional fire-fighting departments.
In response to a question from Dr.Zudans, Mr. Schott noted that Kaiser Engineers, the constructor for the Zinvner plant, will be responsible for fire protection during the construction phase. After completion of the plant, the in-plant fire protection group of the CG&E will assume the responsibility. However, the transition phase of this issue has not yet been clearly defined.
Mr. Bender suggested that the NRC Staff carefully look into the aspect of transferring the responsibility for fire protection from construction phase to the operating phase, l
Quality Assurance and Quality ' Control Programs - Mr. J. Schott I
Mr. Schott reviewed the quality assurance and quality control progres formulated for the Zimmer plant. 'Ihe quality assurance programs consist of managerial, administrative, and operational controls and procedures i
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Zimmer. November 17, 1978 used to assure the safe operation of the plant. All safety-related operating, maintenance testing and modification activities are con-ducted in accordance with the written procedures approved by the Plant Operating Review Committee.
Industrial Security - Mr. J. Schott Mr. Schott noted thet the security plan for the Zimmer plant is in conformance with the requirements delineated in Regulatory Guide 1.17,
" Protection of Nuclear Power Plants Against Sabotage". A revised security plan intended to meet the requirements of 10 CFR Part 73.55 had been submitted to the NRC Staff in May 1977, and it is being re-viewed by the Staff.
In response to a question from Mr. Bender, Mr. Schott noted that they.
call upon the local police, which is a small organization, under certain circumstances. mwever, the basic responsibility for offsite security support lies with the Clermont County Sheriff. 03&E has radio communi-cations with the Sheriff's dispatcher.
In the event of,an emergency, they expect help from the Sheriff's office within ten minutes.
In addition, they can also call the nearby Ohio State Patrol for assistance as required.
Quality Assurance and Quality Control Experience for the Zimmer Plant -
Mr. Schwiers Mr. Schwiers provided an overview of the quality assurance and quality.
control activities at the Zimmer plant site. G3&E involves mostly in the quality assurance activities. & wever, there are certain depart-ments within CG&E who involve in the quality control activities. Kaiser Engineers, the constructors for the Zimmer plant, are basically responsible for most of the quality control activities.
7he quality assurance and I
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Zirnmer November 17, 1978 quality control requirements are inc1Med in the equipnent specifications prepared by Sargent & Lundy, the Architect Engineer for the Zimmer plant.
With the assistance of the Kaiser Engineers" Quality Assurance Division, CG&E.will perform the necessary audit to assure that the requirements delineated in the eqiupment specifications are fully complied with.
Mr. Schwiers noted further that Region III of the NRC has conducted about 70 inspections at the Zimmer plant site, and identified about 65 non-compliances. Mast of the non-compliances are considered in-fractions and the rest are considered deficiencies. He indicated that l
all of the non-compliances have been resolved satisfactorily.
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Mr. Schwiers discussed some of the quality assurance and quality control experiences encountered at the Zimmer plant (Attachment I).
In response to a question from Mr. Bender concerning the nature of the work performed on the recirculation pumps, Mr. Schwiers noted that the bearings of the recirculation pump motor at the Zimmer plant was changed as sixjgested by the supplier of that pump. He a$ded that it was not a specific problem to the Zimmer plant; it was identified as a generic pro-i blem by the supplier of the recirculation pump after experiencing failure of one of the recirculation pump motors in another nuclear power plant.
In response to another question from Mr. Bender regarding the role of Sargent & Lundy, the Architect-Engineers for the Zimmer plant, in examining the installed products at the Zimmer plant site, Mr. Schwiers noted that Sargent & Lundy does not have any responsibility to review I
any of the installed products.- Their main function is to prepare equipnent specifications and design drawings. CG&E, in conjunction with the Kaiser Engineers, has the responsibility at the site to assure 1
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that the design documents are implemented and are completely complied with, ibwever, Sargent & Lundy Engineers constantly visit the site, at least once a month, to check and make sure that the design is properly interpreted.
Mr. Bender wondered at the role of the constructirx3 engineers as com-pared to that of the design engineers in checking the adequacy of the final 6 Mign. He suggested that the NRC Staff provide a compari-I son of the quality assurance and quality control programs for the Zimmer plant with those for some other plants.
DISCUSSION OF OUTSTANDING IESUES - MR. I. PELTIEn, NRC STAFF Mr. Peltier provided a brief summary of the (tems that remain outstanding as of November 2,1978, the date at which a draft copy of the Safety Evaluation Report was issued. A brief discussion of some of the cut-i standing items are as follows:
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Dewatering of Compacted Backfill We NRC Staff's position on this issue calls for dewatering f
I of the compacted backfill under a seismic Category I struc-ture. %e NRC Staff's position also states that the water 1
level in the compacted backfill should be maintained at or below 457 feet mean sea level elevation.
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l Cincinnati Gas & Electric Company (the Applicant) has agreed to provide a seismic Category I structure. Ibwever, the Applicant has not agreed with the NRC Staff on the maximum water level that should be permitted. He feels that excessive floor pressure in the compacted backfill l
can be prevented even by maintaining water level at 480 feet mean sea level elevation as agreed upon during 1
the construction permit stage.
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Zimmer November 17, 1978 Mr. Peltier indicated that this issue is being reviewed by the IRC Staff and its consultants and a resolution is expected in the near future.
Reactor Vessel Supports
%e Applicant has provided the necessary information re-quested by the NRC Staff such as the forces and moments on the reactor vessel resulting from a Ioss-of-Coolant Accident.
We tEC Staff has been performing independent analyses to verify the information submitted by the Applicant.
Rey do not anticipate any problems on this issue and expect to resolve it in the near future.
Preservice and Inservice Inspection Program
%e Applicant is revising the preservice and inservice 3
I inspection programs to include an acceptable inservice i
inspection met. hod for an early detection of feedwater j
and control rod drive nozzle and blend radii cracking.
He plans to submit this revised program six months prior to the commercial operation.
Effects of Recirculation Pump Trip in Overpressurization Analyses
%e Applicant did rot include the effects of recirculation
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pump trip in the overpressurization analyses. %e NRC Staff has asked the Applicant to include this effect in his analyses, and and also requested him to provide a sensitivity analysis for the effects of initial operat-ing pressure in the vessel dome.
In addition, the NRC l
Staff requested the Applicant to provide more pertinent f
j data on the operating experience and qualification j
testing of the safety / relief valves.
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Physical Separation and Electrical Isolation he Mtc Staff has identified several deficiencies in this area. he Applicant has agreed to make the neces-sary modifications to resolve the problems identified by the NRC Staff. He also agreed to parfonn qualifi-cation testing of electrical isolators used between I
redundant safety systems circuits, and ron-safety grade and safety grade circuits.
Design for Pool Dynamic Lods
%e Applicant has been reassessing various structures, systems, and components,by usiryg different load com-bination methodologies proposed by the NRC Staff. Those structures, systems, and components fall into the following three categories:
1.
Those which meet the code stress limits
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when dynamic loads are combined by the
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absolute sum method.
2.
hose which meet the code stress limits when dynamic loads are combined by the square root of the strn of the squares method where applicable, but do not meet the code stress limits when the loads are combined by the absolute sum method.
The Applicant has requested permission from the NRC Staff to apply this method 7
on a case-by-case basis.
3.
'Ihose which do not meet the code stress limits when dynamic loads are combined by either the absolute sum method or the square root of the sum of the squares method. For those systems which fall into this category, the Applicant is analyzing the loads by usire the absolute sum method,
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Zimer November 17, 1978 and inodifying the systems as necessary to meet the Code stress limits.
Low-pressure Coolant Injection Diversion Effects on ECCS and Long-term Cooling The Applicant's design diverts automatically the low-pressure coolant injection flow to the wetwell sprays after ten minutes in order to increase the allowable bypass of the suppression pool during a small break LOCA. The NRC Staff has requested the Applicant to analyze the effects of the low-pressure coolant injection diversion on ECCS and long-term pool cooling and show that any core temperature increase is within accept-able limits.
The NRC Staff has not yet received all the necessary information l
pertinent to this issue.
Pool Dynamic Loads and Load Combinations The NRC Staff has issued its acceptance criteria for the Mark II l
containment design to accommodate' pool dynamic loads (NUREG-0487).
If the Applicant takes any exceptions to these criteria, then the i
NRC Staff will. review those exceptions and provide its position.
This issue is expected to be resolved.in the near future.
Safety-related Dispay Instrumentation The NRC Staff has identified ame unacceptable designs in the area f
of safety-related display instrumentation (e.g. rod display system powersource).
The Applicant has proposed some modification: to ensure the availability of rod scram indication in the event of power source failure during an event requiring rod scram.
All Other Instrumentation Reqdf red 'or Safety The NRC Staff may not be able to cele to a final position on this t
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issue until they reach a final position on'the use of non-safety grade equipment for the mitigation of abnormal transients.
APPLICANT'S RESPONSE TO NRC STAFF'S
SUMMARY
ON OUTSTANDING ITEMS Mr. Flynn stated that CG&E basically agress with the information provided by the NRC Staff on the outstanding issues. They will provide complete cooperation to the NRC Staff for early resolution of the outstanding issues.
In relation to the issue on the pool dynamic loads and load combinations, Mr. Brinkman noted that the Mark II containment owners group is reviewing the NRC Staff's acceptance criteria. Major portion of the NRC Staff's criteria seems to be acceptable to the Mark II owners group. The areas in which they do not agree with the NRC Staff will be discussed and re-solved in the near future. However, if necessary, the Zimmer plant will be more flexible than the Mark II owners group in accepting the NRC Staff's criteria.
In response to a question from Dr. Zudans regarding the adequacy of the 4
downcomer design, Mr. Brinkman noted that the downcomer for the Zininer plant was designed by Sargent & Lundy. They performed an aralysis of both the static and dynamic loads; the results of the analysis show that the loads are within the capability of the downcomer.
Dr. Plesset suggested that since this is a generic problem for the Mark II containment plants, it may be discussed in detail at the ACRS Fluid Dynamics Subcommittee meeting scheduled to be held at San Francisco on
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November 28-30, 1978.
f In relation to the NRC Staff's concern about the adequate performance of the non-safety grade equipment during some abnormal transient conditions, l
Mr. Johnson from the General Electric Company remarked that there is no l
definitive data to prove that the non-safety grade equipment will not l
operate during abnormal transient conditions. He believes that these j
equipment have some degree of reliability and it is appropriate to consider these operable during some abnormal transient conditions.
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Zimmer November 17, 1978 In response to a question from Dr. Zudans regarding the settlement of the foundation mat. Mr. Crail from CG&E, noted that they are continuously mea-suring the settlement at various points throughout the plant and all the information pertinent to this matter are documented.
In response to another question from Dr. Zudans regarding the qualification of the energy absorbing capability of the pipe whip restraints, Mr. Rurka noted that these restraints are designed for energy absorption. Mr. Bosnak from NRC Staff added that General Electric Company has conducted a series of tests on these restraints.
Mr., Bender suggested that the NRC Staff provide in writing the technological basis for the design of these pipe whip restraints at a near future date.
RESPONSE TO SOME QUESTIONS RAISED BY THE SUBCOMMITTEE AND ITS CONSULTA IN THE MORNING SESSION I
In relation to an earlier question by Dr. Catton concerning the vulnerability l
of the control rod drive tubes to withstand the consequences of the failure of one of the recirculation pipes, Mr. Brinkman noted that there are two banks of control rod drive modules located about 180 degrees apart. Control rod i
drive tubes are arranged in a lattice pattern such that there is an even distribution of the tubes in each banks.
If the tubes in one bank fails, reactor shutdown can be accomplished with the use of the remaining 50-percent of the tubes in the other bank.
In addition, boron injection system can also be used as a backup system to the control rod drive system to accomplish the reactor shutdown.
With regard to an earlier question from Dr. Zudans as to how the integrity l
of the drywell concrete is maintained at accident temperatures, Mr.
Krishnaswamy, with reference to Figure 3.8-30 (Attachment J) of the Final Safety Analysis Report, noted that the maximum temperature of the concrete after one hour of the accident is about 140 F, after 20 l
hours about 175 F, and after 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> it is about 160 F.
The integrity of the concrete is maintained because the containment is designed for both steady state and transient thermal gradients.
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L Zimmer November 17, 1978 In response to a question from Dr. Catton regarding the value of the i
heat transfer coefficient used for the thermal coupling of the containment atmosphere to the liner, Mr. Krishnaswamy noted that he will provide the information at a later date.
In relation to another earlier question from Dr. Zudans as to whether any analysis has been performed to show that the icng and slender down-comer will stay in place as needed, Mr. Krishnaswarqy noted that the down-comer was designed for a static load of 8.8 kips.
The frequency of the downcomer is some where between 4 and 5 hertz when it is empty.
When additional mass is added because of water, the frequency will be lower.
He edded that the static load produces a maximum moment of 300 Ft.-Kips, and the dynamic load produces about 120 Ft.-Kips.
Therefore, the dynamic load produces smaller effects compared to the static load which is more conservative.
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i In response to a question from Dr. Catton regarding the time at which
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r chugging is nearing completion and the maximum pool temperature at the l
end of chugging, Mr. Crawford from Sargent & Lundy noted that he will provide the information at a later date.
Dr. Butler, NRC Staff, indicated that. they will look into this issue and provide the appropriate information at the Subcommittee meeting on l
Fluid dynamics scheduled to be held at San Francisco on November 28-30, 1978.
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1 STATUS OF MARK II CONTAINMENT ISSUES - DR. BUTLER NRC STAFF i
Dr. Butler provided a brief sumary on the status of the Mark II containment issues. He noted that the NRC Staff has recently issued NUREG-0487, " Mark II Containment Lead Plant Program Load Evaluation and Acceptance Criteria " which l
delineates NRC Staff's acceptance criteria for Mark II containment plants.
The Mark II owners group has been requested to examine the bounding loads 0FFICIAL USE ONLY 4
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Zimmer November 17, 1978 prescribed in the document NUREG-0487. to determine whetfier they could meet the NRC Staff's criteria. After examination of this document,
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the Mark II owners group feels that they'need to take some exceptions to the NRC Staff's criteria. ~ He believes that Zimmer being a lead Mark II plant could proceed with fewer exceptions.
Dr. Butler reviewed. some of
.those outstanding issues pertinent to Zimmer plant:
1.
Asymmetric pool swell loads 1
2.
Safety Relief Value (SRV) bubble phasing and frequency 3.
Loss-of-Coolant Accident SRV submerged drag load.
Dr. Butler indicated that the Applicant has committed to perform necessary analyses in some areas to provide additional infonnation for the resolution 4
of the outstanding issues.
He added that subject to the resolution of the Square Root of the Sum of the Squares (SRSS) load combination metho'd i
for the SRV and operating basis earthquake loads, the NRC Staff believes that the issues associated with LOCA pool dynamic load can be found resolved in the near future.
i, With regard to a question from Mr. Bender regarding the reasons for cutting the flanges off the downcomer and also in relation to.a question from Dr. Zudans as to whether there are any test data to replicate the close spacing of a fairly large number of downcomers, Dr. Butler noted that he would provide the appropriate information at the Fluid Dynamics Subcommittee meeting scheduled to be held at San Francisco on November 28-30, 1978.
APPLICANT'S RESPONSE TO NRC STAFF'S PRESENTATION ON THE STATUS OF MARK II CONTAINMENT ISSUES - MR. BRINKMAN, CG&E Mr. Brinkman provided a brief response to the NRC Staff's presentation on I
the status of the Mark II containment issues.
He indicated that the Applicant is in agreement with the information provided by the NRC Staff on this issue.
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Zimmer November 17, 1978 Applicant's approach to handle these issues, and some of the plant modifi-cations performed to meet the NRC Staff's criteria (Attachment K).
STATUS OF ACTIONS ON ACRS GENERIC ITEMS - MR. I. PELTIER, NRC STAFF Mr. Peltier reviewed the actions taken by the NRC Staff in resolving the ACRS generic concerns. The action by the NRC Staff on some of the ACRS generic concerns are discussed below:
j Stress Corrosion Cracking With regard to ACRS generic concern on the stress corrosion cracking, Mr. Peltier indicated that, as a result of several incidents of intergranular stress corrosion cracking occurred in some of the operating plants, the NRC Staff had formed a special task group to investigate this problem.
The results and conclusions of the task group are outlined in NUREG-75/067,
" Investigation and Evaluation of Cracking in Austenitic Stainless Steel Piping of Boiling Water Reactor Plants".
Mr. Peltier noted that the Applicant has been incorporating the i
recommendations of the task group by making necessary design changes so as to preclude or minimize stress corrosion cracking problem.
However, Mr. Peltier added, there were several other stress corrosion cracking incidents experienced recently in some of the operating plants. Because of these recent incidents, the NRC Staff feels that this problem may have to be discussed further with the Applicant so as to identify and incorporate additional mean:., as necessary, to preclude the occurrence of similar type of incidents experienced recently.
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Zimmer November 17, 1978 Loss of Onsite and Offsite AC and Reliability of DC Power Systems l
Mr. Scholl, NRC Staff, indicated that the reactor core isolation I
cooling system for the Zimmer plant is a turbine driven system.
The speed controls for the turbine system come off of an inverter which is connected to a de power source. Therefore, in the event l
of loss of ac power, the plant is capable of operating for at least 30 minutes just with the de power source and the stored steam in the reactor vessel.
In addition, Zimmer plant has three full-size diesel generators to supply power as necessary in the event of loss of ac power.
The de power system in the Zimmer plant has three divisions. There-fore, loss of one division will not create any problems.
In addition, Zimmer plant is provided with battery monitors to determine whether the battery is connected to the dc bus.
In response to a question from Mr. Bender regarding the minimum time for restoring offsite power subsequent to a flood, Mr. Scholl i
noted that restoration of the power depends on the magnitude of the flood and the damage caused by it to the distribution systems.
Therefore, he may not be able to set a minimum time for restoring the offsite power.
Instrumentation Follow the Course of An Accident Mr. Peltier indicated that the requirement delineated in Regulatory Guide 1.97 for instrumentations following the course of an accident will not be applicable to Zimmer plant.
It is applicable to plants docketed after September 30, 1977.
Mr. Israel added that implementation of Regulatory Guide 1.97 is not definite at this time, and also it is not intended to be implemented at the Zimmer plant.
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Zimmer November 17, 1978 Mr. Bender expressed concern about the NRC Staff's attitude in not pursuing this matter more vigorously. He noted that the NRC Staff's position has not been made clear to the ACRS, and the ACRS did not indicate that it would accept a position that all the existing plants will not have to be monitored further.
He suggested that the NRC Staff has to look into this matter very carefully and decide what it plans to do in response to this issue.
i Recirculation Pump Overspeed During a LOCA Mr. Peltier noted that the NRC Staff is still reviewing this issue. The Applicant's position on this issue is that parts of the impeller cannot form destructive missiles because of the restraints.
The NRC Staff does not have a definitive position on this issue. However, after completion of their review, they may require decouplers if it is found necessary.
In response to a question from Mr. Bender, Mr. Peltier noted that the NRC Staff may not be able to reach a decision regard-1 ing the use of decouplers prior to the issuance of operating license for the Zimmer plant.
Mr. Robare from General Electric Company noted that they studied this problem and submitted a report to the NRC Staff providing justification that decouplers are not needed.
In response to a question from Mr. Bender as to why Germans have decided to use decouplers, Mr. Robare noted that the results of a-previous study on this issue indicated that decouplers would be helpful and advisable.
He thinks i
that the Germans might have decided to implement the recommenda-tions of that study.
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Mr. Bender suggested that the NRC Staff look into this problem and determine the bases for the German action and also decide i
whether using decouples is a good idea or not.
Loose Parts and Vibration Monitoring Mr. Peltier noted that the Applicant has committed to install loose parts monitors at the Zimmer plant. Two sensors, capable of detecting a loose part impacting with a kinetic energy of i
0.5 ft.-lb. within 3 feet from the sensors, will be installed at each natural coolection region in the primary system. There is no vibration monitors installed at the Zimmer plant and the NRC Staff does not intend to require any vibration monitors for the Zimmer plant.
In response to a question from Dr. Zudans regarding specific design provisions at the Zimer plant for precluding water hamer problem, Mr. Israel noted that operating experience indicates that one of the recurring causes for water hamer in the BWRs is
' voided lines in ECC systems. Zimmer plant uses Jockey pumps i
to keep these lines filled with water all the time to preclude this problem.
Other types of water hammers such as the one caused by valve closings and openings have not appeared to cause signi-ficant problems so far.
APPLICANT'S ACTION ON ACRS GENERIC ITEMS Mr. Brinkman indicated that the Applicant has developed a inservice inspection program for detecting the cracks at nozzles and has been discussing this with the NRC Staff.
He believes that the Applicant is in agreement with the NRC Staff on this issue and the inservice inspection program will be included in the FSAR through one of the future amendments.
In relation to the issue on the Anticipated Transients Without Scram, Mr. Brinkman noted that the Applicant has been following the discussions 0FFICIAL USE ONLY
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o Zimmer November 17, 1978 l
l on this matter and he has proposed some solutions for the Zimer plant.
If it is acceptable to the NRC Staff, the Applicant will incorporate l
those solutions in the Zimer design.
In relation to the issue on instrumentation following the course of an accident, Mr. Schott noted that Zimmer plant has a Seismic Category I post-LOCA monitoring system. The radiation monitoring portion of that system consists of redundant ionization channels that provides readi6gs in the control room.
This system continuously monitors the containment atmosphere.
They also have provisions to predict the dose levels at the site boundary, low population zones, and at any point up to 50 miles located in the direction of the downwind.
SUBCOMMITTEE REMARKS After the presentation by the NRC Staff and the Applicant, Mr. Bender commented that the Subcommittee is not too happy about
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the way the NRC Staff is handling the issue on instrumentation following the course of an accident. The Subcommittee would like to hear more definitive information on this matter prior to i
recommending the Zimmer operating license application to the ACRS full Committee for review.
He also noted that depending on the outcome of the Fluid Dynamics Subcommittee meeting scheduled to be held at San Francisco on November 28-30,1978, the Subcommittee may wish to have another meeting to discuss some of these
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issues.
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Mr. Bender indicated that he would recommend this project to the ACRS l
full Committee for review in the near future subject to the resolution of several concerns raised by the Subcommittee during the course of the meeting and also subject to the issuance of the final version of the Safety Evaluation Report by the NRC Staff.
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