ML20153C341

Trip Rept of 870302-13 Visit to Ussr by Nrc/Doe Nuclear Safety Team

ML20153C341
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Issue date:	03/02/1987
From:	Barber R, Gavigan F NRC
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JCCCNRS-GENERAL, NUDOCS 8805060211
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l REPORT OF A TRIP TO THE USSR I

BY AN NRC-DOE NUCLEAR SAFETY TEAM (Prepared by R. W. Barber and 7. X. Gavigan)

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March 2-13,1987 l

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s 8805060211 880318 I E PDR C RES i

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CONTENTS I.

SUMMARY

II.

TRIP REPORT III. APPENDIX e

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I.

SUMMARY

Visit of Nuclear Safety Team to USSR March 2-13, 1987

1. Francis X. Gavigan, Director Robert W. Barber, Director Office of Advanced Reactor Programs Office of Nuclear Safety (301) 353-3134 (301)353-3548 Office of Nuclear Energy Office of Environment, Safety and Health -

2. Brief Itinerary State Committee for Utilization of Atomic Energy, Moscow March 2, 1987 Kurchatov Institute, Moscow March 3, 1987 Zaporozhiye Nuclear Powerplant, Energodar March 5, 1987 Ministry of Health of the Ukrainian S.S.R., Kiev March 6, 1987 Chernobyl Nuclear Powerplant, Chernobyl March 6, 1987 Izhora Fabrication Plant, Kolpino March 9, 1987 Atomenergoproyect, Leningrad March 10, 1987 All-Union Scientific Institute for Operation of Atomic March 11, 1987 Powerplants Moscow Beloyarskaya Nuclear Powerplant, Beloyarsk March 12, 1987 l State Comittee for Utilization of Atomic Energy, Moscow Harch 13, 1987

3. Purpose '

A U.S. Government team made up of employees of the Nuclear Regulatory 1 Comission (NRC), the Department of Energy (DOE), and National  ;

Institutes of Health visited USSR government organizations, reactors, I and research institutes to explore potential areas for cooperation between the United States and the Soviet Union under the auspices of the U.S.-USSR Agreement on Cooperation in Peaceful Use of Atomic Energy signed by Nixon and Brezhnev, June 21, 1973.

4. Abstract .

Increased attention is being paid to safety measures in the USSR following the Chernobyl accident. An intensified interest in administrative matters and regulatory procedures was evidenced as was the use of passive safety design features in district heating reactors, PWR's, and RBMK's. Efforts are underway to improve the safety of developing reactor designs to assure that plants built in the future under the expanding USSR nuclear energy program will more closely reflect international standards and approaches to management, training, and design. A protocol for future cooperation including a reciprocal visit by a USSR team to the United States in October-November 1987 was signed on March 13, 1987.

5. Recommendations o Discussions for future cooperation should continue.

o The visit to the United States, agreed in the protocol, should include, to the extent possible, similar facilities and activities as were included in the l!.S. team visit to the USSR.

o Final infomation exchange agreements should cover the areas with potential benefit to DOE, such as lessons learned across a broad safety spectrum from the totality of the Chernobyl accident, process heat reactors (High Temperature Gas Reactor (HTGR)), and

• severe accident analysis and recovery methods.

o Efforts should be made to obtain more safety design and operating infomation (,n the VVER 440's and 1000's.

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II. TRIP REPORT A trip to the USSR was conducted from March 2-13, 1987. Major reactor sites were visited, and a number of discussions were held at USSR Institutes and with the State Committee for Utilization of Atomic Energy .

(SCAE). l A report of the discussions and descriptions of some of the key facilities visited is given below. The Appendix contains a list of team members, an itinerary, a list of Soviet officials visited, and a copy of the protocol that was signed.

• Meeting with the SCAE on Monday, March 2, 1987 ,

o A. Petrosyants opened up with a welcome and introduced Mr. Semenov, l Mr. Sidorenko, Mr. Voronin, Mr. Yamokov, and others and apologized for l the non-appearance of Mr. Malyshev, the new head of the USSR NRC (The State Comittee for Supervision of Nuclear Power Saf'e ty) who was in the hospital. A. Petrosyants stated that DOE had not yet stated whether it was interested in a follow-up meeting of the joint comittee that had met in August at Vienna. This meeting had been attended by A. Trivelpiece, J. Vaughan, and J. Griffith.

o A visit to Chernobyl was negotiated but limited to three people by the  !

USSR. In addition, Petrosyants stated that we would hear about the l Cuban reactors when we got to Leningrad. NRC provided a copy of i NUREG-1250, Analysis of Chernobyl Accident. This was followed by many l questions from the USSR concerning NRC authority to shut down reactors and the relationship of NRC to DOE operations. 1 o The USSR presented a general description of the total USSR nuclear '

program including the BN-800 fast breeder (under design), the two district heating plants, one at Gorky (almost complete), and another at Voroyonesh, as well as the planned 400-MWt helium-cooled pebble bed reactor, o The point was made that safety is going to be emphasized to decrease probability of accidents and to increase the safety of existing reactors and especially to aim at the development of new designs. They want to use passive means for shutting down and cooling and to rely on improved diagnostics and automation as well as increasing the qualifications of operating staff and inspectors. It is the USSR intention to undertake increased activity in the development of new inherent features to withstand severe failures. They are also pressing for improvements in standards, procedures, and documentation and more strict safety requirements for site choice, design, construction, operation, and repair as well as establishing simulator training centers at which the standardized plant operators can be qualified and recertified as well as trained, o There was much interest shown in the NRC program on core melts and containment modifications, e.g., the NRC position on MARK-I BWR's. NRC described their R&D program on core melts and their approaches to

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containment. This was followed by a lengthy discussion on quantitative criteria such as those contained in NUREG-0880 as well as discussions on PRA and its utility, NRC passed out Volume I of NUREG-1150.

o The USSR stated that in the future serially mass produced reactors will use standardized containments, but they have done no core melt research similar to the United States. However, since the USSR intends to increase the power of future plants and the number of future plants, they wish to reduce overall risk by developing stronger containments and by designing for core melts. .

o V. Sidorenko heads the SCAE Supervisory Comittee that was fonned 3 years ago and is in fact the USSR NRC and functions under Mr. Malyshev. This comittee supervises all stages of a plant from

• 1 site choice through decomissioning. Organizational 1y, they have units for control, administrative supervision, design, production, operation, and R&D, However, there is not yet sufficient staff to perfonn all the tasks. They have 500 people, including the regional staff, of which 150 are assigned to headquarters. There are six regions with three to five inspectors located at each site as well as inspectors within the design group. There was interest in the people distribution inside of

-= NRC Headquarters including how many people were. used as inspectors in the field. Safety research is going to be increased in the future and is conducted by SCAE.

o Radiation exposure regulation is carried out by the Minister of Public Health. The State Committee for Meteorology and Environmental Protection also has regulatory jurisdiction. If you compare the USSR and IAEA radiation protection standards, there is little difference in principles, but the USSR has a wider scope due to their national problems. Generally, use is made of ICRP standards modified for Soviet situations.

o In regard to nuclear power regulation, there are 150 major documents that presently comprise all the rules and nonns used by USSR. However, there are thousands of subtier documents. These are developed by other '

Ministries and the SCAE supervises and coordinates. After Chernobyl, ,

documents were reviewed, and new ones were added. More documents are I being prepared.

o The Ministry of Machine Building builds the reactors. The Minister of Nuclear Power orders equipment from other ministers. Final pennission

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comes from the Council of Ministers and is issued by the State Comittee on Supervision of Nuclear Power. Three separate approvals are issued at site selection, construction, and operations. Other ministers also issue approvals, e.g., the Minister of Public Health issues his own, the Minister of Supervision of Pressure Vessels issues his own, etc.

o The Council of Ministers approves the general energy plan. The Ministry of Power and Electrification sells power to municipal councils and to industries. Ninety percent of the plants are owned by the Ministry of Power and Electrification. It also sells power to other Ministries. The price varies by region and conditions of supply but 1.s generally regulated at,the top by the State Planning Comittee.

3 o A number of questions by the USSR on design criteria used by the United States for containment vessels including airplane crashes followed.

o The USSR has not set quantitative reactor safety requirements yet but agree with the statement that the core melt probability should be less than one in 4,000 reactor years. For the next 10 years, they are going to look for technical solutions to strengthen existing reactors. But for the next generation of reactors, they will consider a new design and quantitative design criteria for reducing radioactivity releases and for accomodating the core melt. Their philosophy is that present designs are acceptable, but the USSR must consider the total risk of an increased population of reactors. The next generation of water-cooled powerplants will have to meet the new requirements but channel type

• reactors (RBMK) are different. They are preparing PRA's for existing plants and those under development. The United States is ahead of the Soviet Union in this area, o Discussions ensued on the differences between NRC and INPO. They have t a strong interest in INP0 and noted that they r. ave an organization that does similar things. There also was interest in the large research _]

budget of NRC and its distribution for certain R&D areas. The Soviet Union does not have as large a budget for Light Water Reactor (LWR) I safety research. They have decided to form their own safety research scientific center, but it will not include radioactive waste in its i scope. '

1 o Semenov sumed up the meeting with a hope for cooperation "that did not happen in 1978." This is in reference to a break in discussions under  !

the 1973 agreement that was caused by the USSR invasion of Afghanistan.

Visit to the Kurchatov Institute, March 3, 1987 o The Institute has three missions, i.e., neclear power development, fusion, and technical support (metallurgy and physics). Generally, this design institute develops concepts, perfonns feasibility studies, tests features, and makes a decision on the viability of a design. If viable, the design is passed to a full-scale design organization for  !

further development. They work on risk analysis and gas and water-cooled reactors. Fast breeder development is located at the Physics and Power Institute near Moscow, o The agenda for the day called for discussion of VVER-1000, district heating reactors, and HTGR's. In addition, the USSR wanted to discuss their capability that is not yet fully developed in safety computer codes, the role of PRA, and the potential consequences of core melt.

o Forty-four VVER's have been built in the range of 70-1000 MWe. The most comon size is 440 MWe, Bulgaria will soon have the first 1000-MWe plant outside of the USSR. The major differences between U.S., French, and USSR PWR's are the clad, i.e., Zr-Nb; forged reactor vessels with extruded nozzles with no circumferential welds in the belt region and no longitudinal welds; large horizontal steam generators with stainless steel tubes; no bottom vessel penetrations; and large pressurizers (2 times U.S. volume). Reactor vessels must be transported by rail, and hence the cores are compact and have high

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power density. They have steel fuel pin spacers and attain burnups of 30-40,000 MWD / ton. Pressurized thennal shock is not a problem, because they have moved circumferential welds far up from the core belt region, lowered the copper cnd phosphorous requirements of the carbon steel, removed a row of fueled subassemblies, added shield assemblies on the outside of the core, and have used heated water introduction for ECCS operation, o They described the YYER-1000 safety systems that are much like a i ECC pumps, etc. However, they are l U.S. design infortenns not designing station of blackout redundancy,(considered incredible), do not have system or component diversity, and do not have hydrogen mitigation systems. A number of changes are being considered for VVER's. They are investigating core catchers, filters to clean steam'and gas. -

hydrogen igniters, use of boric acid, and modifications to the reactor core. Presently all reactors are designed for .4g seismic at ground l level regardless of the site. l o NRC talked about the source-tenn code package that was deposited at the IAEA. The Soviets showed interest in the subject of acoustic emission, LOFT testing, safety computer codes, plans to rupture. full-scale vessels, and use of annealing for restructuring a vessel wall for 40 to 60-year lifetimes, o District heating reactors were discussed next. Two 550-MWt reactors are being built, one in Gorky (almost ready to start up) and one in Vorovonesh. Special safety requirements were added 10 years ago j because of the close proximity of the population. Special features i were added to protect against explosions from liquified natural gas and I aircraft crashes. The primary system is designed for 20 atmospheres l with a 130 degrees Fahrenheit inlet and 208 degrees Fahrenheit outlet.  !

Stored energy is very low and a low power density increases the l reliability of the structures. The reactor can be cooled by natural circulation with an IHX within the pressure vessel. The pressure vessel itself is contained in a metal conta1nment vessel (will take full failure of reactor vessel), and everything is installed in an underground silo. The core cannot be uncovered. The linear heat rate is90wattspercentimeterwith270wattspercentimetermaximum(121 fuel assemblies). An accumulator of boric acid is used for backup shutdown. There are 3 coolant loops and 30 control rod drives mounted ,

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on the reactor head. There are 250-cubic meter tanks of water in the secondary piping to give 5 to 7 days of natural circulation cooling.

Radiolysis of gas is prevented by using 96 percent helium and 4 percent hydrogen as a cover gas. Reactor vessel embrittlement is avoided by a large water gap between the core and vessel, o The HTGR was also discussed. It is being developed at two sizes, 1000 MWT and a smaller version at 300 MWT. The smaller one is intended for modular deployment. Ball-shaped fuel (pebble bed) is used with a 6.5 percent enrichment. The outlet temperature of 950 degrees l Centigrade will be approached in three stages during startup. This is

) a four-loop plant with a Russian developed nickel alloy somewhat like 800H Incolloy. For the large version, a PCV containment building will i' be used with 3 atmospheres design capability and 100,000 cubic meters I of volume. The design bases for the building are a loss of cooling

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5 after scram and other requirements. There will be 100 reactors built

in the future. Of those that are of a new design in this planned 3

addition, 25 percent will be HTGR's. By the year 2000, they expect to 3 have the large plant and the small modular plant constructed. The small modular one will be contained in one large single building that has no containment capability.

d gporozhiyeAtomicPowerStation, March 5,1987 I o We visited this large plant at which six 1000-MWe VVER's are to be i

constructed (Units 1, 2, and 3 were in operation). One plant per year has been brought on line in 1984, 1985, and 1986. Initially they 2

achieved a .5 capacity factor that is now up to .7. All plants have

• prestressed concrete containment buildings. The control room was very 4 quiet, and the plant areas that we visited were clean and neat. Fire protection for the control room was simply utilization of hand held C0(2) fire extinguishers; they did not have U.S. required cable separation in control room. A simulator is being designed for Zaporozhiye. Additionally, a central simulator for all of southern USSR is being built, o The plants are operated with five shifts of 32 people per shift that work 3 days on and 2 days off. The crew is made up of a number of supervisors for the reactor, turbine generator, instrumentation and 1 controls, chemistry, health physics, etc. The supervisors have university engineering-degrees, and most of the rest of the crew have

{ technical college degrees. The Chernobyl accident has changed the degree of training and organizational structure with more stress on personnel responsibility and adherence to standards and regulation.

They conduct a health check (a physical examination) on all personnel each day. It was Stated that this was the same process applied to all 2

USSR truck drivers.

} o We toured the turbine generator room (it had a single unit of 1000 MWe), control room, water treatment area, and a diesel generator building. The floor in the turbine generator room shook quite a lot i from vibration. The control room was clean, neat, well laid out, and

. had about 10 large CRT's for plant information. There were three young

! looking operators, no written procedures in sight, and a number of energized red lights that show a system or component is okay. They 4 have a separate emergency control room for shutdown and control of core

cooldown. The plant has three 6-MW diesels that are physically well a separated. They are put on line every 7 days for a check and have nad good startup reliability. The plant only needs one to be safe.

o We toured the health physics and waste control areas and noted extensive off-site monitoring panels showing many sensors in town, near the plant, and some out to 100 km. For the tour we donned Anti-C's and special shoes, were given a pencil dosimeter, and got hand and foot counted twice on the way out. We next visited a large HP control 1 station with numerous badges for the workers.

4 l o We noted that there were many occupational hazards such as slippery l stairs covered with plastic, obstacles on the floor, and workers i without safety glasses. (We received hard hats.)

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6 o The USSR situation on acoustic emission is somewhat analogous to U.S.,

i.e., experimental programs are in place in operating plants but have not yet reached the operational stage. They are performing noise signature analysis on the main coolant pumps.-

o USSR training is carried out differently than in the United States.

The USSR NRC licenses the director of the plant, chief engineer, the deputy chief engineer, and the inspectors. Then, the plant manager licenses all lower level people. There is much more emphasis now on meeting the training and qualification requirements; requirements were in place before Chernobyl, but now the pressure is on implementation.

Every 2 years, a requalification is required. Also, if any problems are reported or if an operator is off for over 3 months, a .

requalification is required. (Later we heard that the requalification requirements were put in place since Chernobyl.)

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, o Emergency planning has not changed since Chernobyl, but more 1

. coordination with the Civil Defense has been implemented. The USSR I forbids any activity within a 3-km zone of the plant. From 3 out to 30 km, evacuation plans.are in effect as is constant monitoring. This

. may be increased to 50 km due to Chernobyl. A third zone is established that is a free zone, but tentative plans are established depending on seriousness of an accident. Meteorological stations make measurements and predictions and give results to the Civil Defense, and then the local Minister of Health takes over. Warnings are given if an iodine release at 3 km is calculated to give a 30 rem or greater dose to a child's thyroid. If 250 rem is calculated, then an evacuation order is given, o They pointed out the advantages of horizontal steam generators versus the U.S. vertical type. They have had good experience in that thennal cycling is not so severe, the pipe bundle is always under' water, there are no interface problems, and the unit's greater heat capacity and therefore time to dryout is much longer. l l

o Discussion with the on-site inspection people indicated that while they '

have three to five people on site (for three reactors), they did not have the authority to stop work and could not describe any serious problems that they had uncovered. Also, they do not conduct on-site inspections with large teams (10-15 people).

Chernobyl Atomic Power Station, March 6,1987 l

o F. Bernthal, H. Denton, and F. Gavigan visited the Chernobyl-1 plant and met with the director of the plant and the director of power  ;

generation for the 30-km zone surrounding the plant. Police escort '

I accompanied the microbus up to Chernobyl from Kiev and on the return trip. It was snowing ill the way. The town of Chernobyl was deserted

except for some occasional activity in the center of town.

o Construction activities on plants 5 and 6 are continuing and it is l

, planned to bring up unit 3 to full power by the end of 1987 and to have l j the new fast control rods installed by the end of 1987. We v sited the i control room where we saw the limit switches that prevent extreme ,

I control rod withdrawal, the core map that showed about 11 new highly 4

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enriched subassemblies already installed, and the reactivity meter that showed that an effective 45 control rods were in the core. We discussed administrative and key controls on the use of safety system  ;

bypasses. The plant was clean and neat, and the control room was quiet. ,

o We viewed the sarcophagus from a distance and took pictures. The sarcophagus is a concrete structure that encloses the damaged  :

Chernobyl 4 plant. Some 60 or 70 sensors are installed in the i sarcophagus measuring temperature, air flow, neutron flux, flama flux,  ;

and vibration. The system is presently cooled by natural c'rculation, '

but forced air cooling is installed and ready to use if necessary.  ;

Flow is 200,000 cubic meters per hour. Air inlet was -10 degrees -

i Centigrade with a 100 degrees Centigrade outlet. Neutron flux from i spontaneous fission was 1 neutron per square centimeter per second.

The gama dose rate is 2000r per hour, and the fission product going up  ;

the stack was ruthenium 106.

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o The director has a computer display in his office that shows all the {

parameters of the monitoring system for the sarcophagus. This on-line system shows location of all the sensors and all of the parameters plotted against time ~ (in months), all in color. The temperature is decreasing on a predictable decay heat rate.

o On March 6,1987, Mr. Barber and seven U.S. delegates not visiting  !

Chernobyl plant held a 2-hour discussion in Kiev at the Ukrainian '

Ministry of Health headquarters with a group of 11 Soviet specialists  ;

in radiation effects headed by the Ukrainian Deputy Minister of Health j Care. Anatoliy Kasyanenko. The U.S. side was led by D. Ross, NRC Deputy Director of Research, and included health effects specialists '

R. Wood of DOE and R. Miller of NIH. Soviet representatives were primarily from the Ukrainian Health Care Ministry and All-Union Center '

for Radiation Medicine of the USSR Academy of Medical Sciences. When fully organized, this new center will contain three institutes, for experimental radiation research, health physics, and long-ters effects studies. The center is temporarily located near the health care ministry in Kiev in scattered buildings, o Soviets in Kiev in general were responsive but not eager for extensive discussions. They gave a broad overview of a very difficult situation after Chernobyl, with health people working day and night to cope with problems. They highlighted the following:

Imediate action was taken to prevent infectious diseases, with no cases reported.

Extensive food and water monitoring was done. Water supply was always 1-2 orders of magnitude below maximum permissible concentration (MPC).

All food products outside 30-km exclusion zone around plant were i suitable for consumption except some dairy products and certain '

berries, i.e., boysenberries and black and red currants.

(Delegation notes this is surprising since other countries imposed '

tighter restrictions.)  ;

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- Special attention was paid to ) regnant women and to children, with all pregnant women evacuated tie first day. Subsequent study showed no differences between mental retardation in births within exposed population and births elsewhere. They attributed this to ,

rapid evacuation of the 1,000 pregnant women exposed throughout the >

Ukraine (about 200 of whom were in the critical period of radiation sensitivity). As a result, none received more than 0.5 rem radiation dose. The delegation notes that this differs from retardation calculations in the U.S. report on Chernobyl (NUREG-1250), which was passed to Soviets in Moscow, since the U.S. report did not assume such rapid evacuation. Soviets also indicated that no reduction in head size was noted in those born after Chernobyl. This is considered a good indication of normal ,

mental ability.

- Whole body counting following accident indicated levels of Cs-137 and I-131 below MPC in Kiev, Leningrad, and elsewhere. (MPC for Cs was stated as the ICRP recomendation.) Later a_SL viet expert said calculations indicate Cs levels were one-ninth MPC Ind whole-body counting indicated one-tenth MPC.

The Soviets said that while some long-term effects on health will occur, they will nc' be statistically observable. However, they do intend to conduct poulation health effects studies.

- At 8 a.m. the day of the accident, teams went to each house to issue potassium iodide tablets. They believe this significantly reduced iodine uptake in the exposed population. ,

Izhora Nuclear Components Production Plant at Kolpino, March 9, 1987 o This is a very large fabrication plant outside of Leningrad founded in 1722 with about 30,000 employees. It constructs a variety of heavy ,

machinery including nuclear components and is a leading plant in the '

USSR. They design and fabricate all primary loop components and  :

! control rod drive mechanisms for the VVER-440's and 1000's. The plant l

uses all the latest methods for NDT inspection, conducts tests on I components such as on CRD's, and does research in metallurgy. They have produced 85 reactor pressure components that have been installed in 22 PWR's including the two units in Finland. Before going to the VVER-1000, they solved two problems. The reactor vessel had to be rail

, transportable, and they had to solve the NDT problem. This is done with forged rings, and no welds in the reactor core region. The l nozzles are also forged with no welds for attachment to the vessel, o They described their NDT program that was based upon experience with the Loviisa plant. They stated that their methods are a bit more 4

stringent than the U.S.-ASME and felt that they had an N-quality code stamp facility. The USSR-NRC type inspectors also check the work at '

this plant. There are site resident inspectors who check the quality at all points including materials supplied.  !

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o A method was described for high quality metal preparation by electro l slag refining and vacuum remelt in batches up to 60 tons. They stated that they use the best equipment they can obtain, foreign or domestic, 1

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i and have a 1200-ton West Gennan made Siemens furnace forging press, j Also have crane capacity up to 1150 tons, which is the world's largest.

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! o On the plant tour, we saw the electro slag refining furnace, a large i rolling mill about 300 feet long, the Siemens forg<ng press, large i capacity cranes, and the pressure vessel assembly shop. They also

noted they were building a 1500-meter long rolling mill.

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o In the pressure vessel assembly shop, we saw many components in various i stages of completion. This included two complete VVER-1000 vessels and

! the Cuban VVER-440 vessel. The vessels had no longitudinal welds, i forged inlet and outlet nozzles, and a circumferential weld some l 12-15 feet above the co-a location. The NOT at fabrication with a '

j special USSR steel was minus 15 degrees Centigrade.

i The Leningrad Division of the Scientific Research and Design Institute, j Ministry of Nuclear Power. March 10. 1987 l o This is the architect-engineer for almost all USSR plants and USSR export plants. Eighty percent of the work is nuclear. They started i design activities in 1931; nuclear station work began in the early 1 1950's. They also designed Beloyarsk and in the 1960's, with the Finns i and Westinghouse, cooperated in designing Loviisa, which has two VVER j 440's. They have also designed a Czechoslovakian and Hungarian i VVER 440, use IAEA standards, and take into account all natural j phenomena, a

l o The Cuba reactor will be two VVER 440's that look like Loviisa and will meet all IAEA standards. Each plant has two loops and two 200-We l turbines at 3600 rpm using sea water cooling. They will meet the local seismic requirements as well as hurricanes and tsunamis requirements.

The site is 8 km south of Cienfuegos. It has a low population density and a 2.5-km isolation zone. The seismic OBE is 6 on an

• scale; the SSE is 8 on an M scale. This translates roughly to a "range of .1 to

.2g for the OBE and .25 to .5g for the SSE." They also design for

.01 percent annual frequency hurricane, tsunamis, and tornadoes. The maximum wind velocity of 180 to 200 kilometers per hour was determined by the tornado criteria. Site flooding criterion was 0.01 percent annual frequency and 10.5 meters above sea level, o Buildings are built to three different categories depending on safety function. The reactor building is reinforced concrete 75 meters in outside diameter with a spherical dome. Construction is ongoing. The turbine hall foundation is in, and the reactor building is one-third complete. Startup is planned in 1990 for the first plant with a second one planned for 1992 or 1993, o The main documentation requirement is contained in the USSR General Provision for Design, Construction, and Operation of Nuclear Powerplants. High quality is strictly emphasized, o The same type plants are being built in Czechoslovakia and Hungary. It is a more modern safety design than the Loviisa plant. Power output will be a little less than Loviisa due to site parameters.

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10 o The DBA is a large LOCA of a 500-m diameter primary pipe. Three totally independent safety heat removal systems are used in contrast to Loviisa. It can also take a station blackout because of three full capacity automatic start diesel generators. Downtime for diesel generators is limited to 3 days. The plant has a remote shutdown station and DC batteries. Each ECCS is totally independent physically, mechanically, and functionally and includes accumulators, pumps, and boric acid supply tanks. Each is laid out around the plant on a 120-degree separation. Interlocks are controlled. The fuel cladding will not exceed 1,200 degrees Centigrade in the event of a DBA.

, o The contairunent is a new design that includes passive acting sodium thiosulphate sprays and a vapor suppression system. The containment building is reinforced concrete, 1.5 meters thick and is designed to

• 0.22 MPa. After the LOCA, pressure increases to .15 MPa and passively activates the spray system while blowing down through the vapor suppression system into another fixed volume. At this time, the lower building is at .08 MPa negative, and any fission products that are emitted have no driving force for emission from the building. The ECCS systems are activated, and a sump in the bottom of the building is used to feed water back to the ECCS. The auxiliary feedwater systems are redundant and are located outside the CV but under the building.

Vacuum in the building is calculated to last for 3 days; some calculations predict as long as 10 days. The CV is lined with 8-m steel plate. The maximum load combination of OBE and DBA is used, and i

_ the building has a safety factor of 2 or 3. The loads used exceed those calculated for the Chernobyl accident. Instead of using hydrogen igniters as in Loviisa, an external recombiner is used in this plant, o The Cubans will be trained in the USSR, and the Soviets will start up the plant and maintain a presence with some degree of control for 4

1 year. There'is provision for 10-year storage of fuel on site prior to shipment to the USSR.

, l o IAEA standards are used for the radiation protection program. This.

1 combined with the containment, results in doses on and off site that are well within acceptable limits. This is true even with a 10 percent  !

core melt. A large scale ecological monitoring program will be put in place 1 year before the plant goes critical. Laboratories for radiochemical analysis will be outside the 2.5-km zone, and some 20 to 30 sampling points will be continually in operation.

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o They do not plan a PRA (insufficient statistics) and rather than a {

PSAR, they have a Nuclear Power Station Operation Limitation Report.

The All-Union Scientific Institute for Operations of Atomic Powerplants, Moscow, March 11, 1987 o We met with Mr. Abagyan, the Head of the Institute. This institute is somewhat akin to INPO. It was founded at the end of 1979. The following are its missions:

1. Conduct R&D based on operating experience of existing plants.

Gather data on failures and enter into a data bank. Work with and make recomendations to industry to lower failure rate and increase

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11 plant lifetime. All work is based upon experience at operating plants. They do quantitative and probabilistic analysis based upon the data bank.

2. Aid in scientific direction of startups. Do materials research at stations during operations and do thennal hydraulics studies on steady-state transients and accidents.

3. Carry out a diagnostics function. Monitor metal condit'on, parts performance, and economic factors, i.e., plant capacity. Conduct physical plant tests at power stations. Do fuel effective use a tests at plants, define safer operating regimes, and plan optimized reloads and station physics activities. Emphasis is also placed on ,

radiation safety and water chemistry.

I 4. Investigate maintenance practices and consider new maintenance philosophies.

5. ' Investigate future plant designs with Kurchatov Institute.

. Investigate better use of waste heat and safer reactor types for the future.

6. They are building test stands to do thennal hydraulics and materials work on valves and fittings. Test stands are to be

, located outside of Moscow because water and electricity is easier to get.

7. Development of systems for operator training is conducted at the village of Yeravan in Armenia. Simulator development is done as well as developing process models for new simulators.

8. The whole Institute was mobilized for Chernobyl and did analysis and consequence limitation studies from the very first hours. Also responsible for improving safety of RBMK's.

This is the only scientific institute working on nuclear power operating safety and will develop recomendations on all types of reactors, o A broad spectrum of specialis'ts are needed to rur, a place like this.

Mr. Abagyan hopes we can have many meetings like this and can cooperate in the future, o In the question and answer session that followed, the following areas were covered: U.S. experience in decommissioning, the limited experience of thi: Institute in this activity, and their reporting to the Ministry of Nuclear Power on powerplant operations. The new inspectorate under Malyshev does not have enough staff yet so this Institute receives prompt information on incidents. They also have special telephone lines from the powerplants. Every morning, a report is sent from the Minister of Power that is processed by this Institute-by computer anal;. sis. Emergency shutdowns or unusual events are evaluated by special groups of experts. Routine operation is reported monthly and analyzed by this Institute first. Also, an annual review

, of plant operation is made of all good and bad practices to improve

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i 12 operations and is conducted for and passed on to all plant Chief Engineers. If experience indicates design or manufacturing problems, it is passed on to those responsible, o Steps are being taken to improve infonnation sharing such as that from  ;

the Chernobyl accident. Fault tree methods of analysis are being I developed to better understand reasons for equipment failure and to improve reliability, o The Institute,is developing a set of large-scale thermal / hydraulic separate and integral effects experiments. These will' simulate accident and transient modes, large and small scale. Mathematical modeling is also being done. Prior thermal / hydraulic work was done by -

the design group under the Ministry of Power. This was more routine, )

whereas, since Chernobyl, accident modes are being stressed.

o Post-Chernobyl, the training problems became apparent. It appears that e operators got lost from sight after graduating from the training institute. Now the USSR will create a special retraining and i recertification Institute. Emergency response training was not done in the past but will in the future. Training begins 2 years before startup at each site. An annual review on operation experience is 1 published. Simulators are being set up at each site especially for l accidents and transients. Plant preventative maintenance is being  !

looked at with a plan to change it from a fixed-basis to a real status maintenance philosophy that is based on actually understanding failure rates and on diagnostic output.

o For advanced reactors, the goal is to minimize activa components, emphasize natural circulation, forbid power bursts, and prevent loss of cooling. An example of such a reactor is the one that has been ,

constructed at Bilibino as well as gas-cooled reactors. The Soviets l are also improving existing reactors. The RBMK's positive void coefficients is a particularly large effort. Additional absorbers, annular voids in the graphite, and a faster control rod system are planned. The. advanced reactor of the future may be modular, gas, or I water. HTGR may be the way to go if they can solve the metallurgy and I chemistry problems.

o Expert systems and artificial intelligence work is being done by universities under contract to Kurchatov.

Beloyarskaya Nuclear Powerplant, with BN-600 Fast Breeder Reactor, March 12, 1987 o We met with the director of Beloyarsk, Mr. Seraev, and his staff in their large meeting room. There are three reactors at the station:

one RBMK of 100 MWe has been shut down, another of 200 MWe (down rated to 160 MWe) that will operate to 1994, and the BN-600. The BN-600 was at approximately 50 percent power and coming up to full power after removal of a leaker the day before. This plant has been well described in other places so rather thts give a description, we will point out some key features. The BN-600 started up on April 8, 1980, and operated at 30 percent to 80 percent power level in 1980. In the last

l 13 4 years, the capacity factor has ranged from 72 percent to 73 percent.

The average since startup has been 62 percent.

o When the plant was designed, there were no special seismic design criteria used so they assumed a value of 5 on a scale of 12. They are now doing a reanalysis because of a post-Chernobyl review.

o Burnup to date is 7 to 7.5 percent ~. The radiation dose to the operating staff is so small it is not worth mentioning. They have had 17 or 18 gas leakers in their subassemblies and 11 fuel failures since first starting the plant.

o They have had a number of sodium fires in which the leaks have ranged ,

from several liters to several tens of liters. These have caused no probler.;s since they simply burned out in closed volumes.

o The malfunctions that have occurred in the plant have been with'two primary pump clutches that were underdesigned. All three pump clutches have been replaced. There 1stso have been leakages at the "end gaskets" of the superheater. These have been replaced with redesigned membranes. The plant is very easy to operate. It generally runs on automatic control with no operator interference. However, Mr. Seraev believes that there is an excess amount of piping, valving, and electrical equipment, far more than an LWR. But as far as the NSSS is concerned, it is very simple to operate and stable. They stated that the sodium-void coefficient for the BN-600 is negative because of the uranium-oxide fuel, o For the future plant design, i.e., BN-800, he expects to see simplified pumps, an automatic reactivity control system, and automatic control of the 80P. The BN-800 will have air-to-sodium heat ex hangers and natural circulation on complete loss of power and a seismic design criterion of 6 on a scale of 12. He believes the BN-800 will be safer and more dependable. The comercialization date for the LMFBR is 1995 to 2000.

o A resident inspector is on site; they use the same safety requirements as for thermal reactors. No' major changes occurred after Chernobyl except to review the procedures and to assure that all changes in procedures and designs are reviewed by Mr. Malyshev's organization. A special review was reassuring since it concluded that no changes in design were necessary. Discussions with the resident inspector left the impression that they are no more in control here than at Zaporozhiye.

o For emergency planning, they assume two kinds of accidents. The first one is a loss of flow with pin-to-pin propagation where 7 subassemblies fail. The other is a pipe break in a pipe leading to the guard tank and external cleanup system. These accidents result in low doses, approximately 100 mr, downwind. The fuel cycle timing is 100 days of operation followed by 20 days for maintenance and fuel removal, followed by 100 days of operation and then 40 days for reactor and turbine-generator maintenance and fuel removal, and then the cycle repeats. After discussing Experimental Breeder Reactor II (EBR-II) tests, they stated that loss of flow without scram was not a design

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i 14 l T l basis accident, and they were not sure anyone would do this test with 1 an oxiae core.

o We were shown a good model of the site and an excellent cutaway of the reactor. We toured the turbine generator room, control room, and  ;

reactor building. They were coming up to power, which takes about i 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br />. There were five operators in the control room. It has some I new instrumentation and controls that included CRT's similar to the i ones at Zaporozhiye. No procedures were evident. It was stated that i

. all the operators were degreed engineers. The same fire protection j approach as at Zaporozhiye was being used. The same procedure was used I at Zaporozhiye to tour the reactor building except we did not get counted on the way out. (Must be due to ver -

the EBR-II and the Fast Flux Test Facility.)yThe low reactor radiation levels like building locked clean, well organized, and was very quiet. We saw fuel handling i equipment, secondary coolant pump motors, and banks of resistors used l to control primary pump coastdown. In a question and answer session, j they noted they have not done any PRA's but plan to. I 1

Closing Meeting, March 13, 1987 l

At the closing meeting, a considerable amount of time was spent

--t o haggling over words in the draft protocol. It was finally agreed to in a shortened fom. It was also agreed to entertain three USSR visitors )

at THI, even though the USSR objected to having it put in the protocol, l and to have an equivalent visit and tour by a USSR nuclear safety l delegation in the United States in October / November at which time l agreement will be reached on areas of cooperation. A. Petrosyants was  !

informed that the meeting of the Joint Comittee will be held in the l United States probably late in 1987 or early in 1988. Mr. Petrosyants was also invited to send a USSR delegation to the NRC LWR safety meeting held in October at the National Bureau of Standards, and they were informed that Comissioner Zech is still interested in visiting the USSR after the USSR delegation visits the United States.

l o Additionally, a straightforward appraisal was made of the Russian program in which they were informed that we thought that they had not I gone far enough yet on the RBMK's and that more work needed to be done l on the older reactors but that they seemed to be making good progress in the improved safety program. Their interest in ARAC was noted for possible future discussion. A. Petrosyants said that if the United States wanted more information on the Cuban reactors, we would have to talk to the Cubans since it is their plant.

o At the Press Conference, a number of questions were fielded by A. Petrosyants and F. Bernthal. A major surprise was the statement by A. Petrosyants that trials will be held in the future at Kicy of the "culprits" who are resoonsible for the Chernobyl disaster.

Recomendations o Discussions for future cooperation should continue.

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15 o The visit to the United States, agreed in the protocol, should include, to the extent possible, similar facilities and activities as were included in the U.S. team visit to the USSR.

o Final information exchange agreements should cover the areas with potential benefit to 00E, such as lessons learned across a broad safety spectrum from the totality of the Chernobyl accident, process heat reactors (HTGR), and severe accident analysis and recovery methods.

o Efforts should be made to obttin more safety design and operating information on the VVER 440's and 1000's.

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