UNSAFE KUDANKULAM REACTORS DUE TO DEFECTIVE EVACUATION PLANS

At Present there is a strong public agitation against the commencement of two nuclear reactors of 1000MW capacity at Kudankulam in the Southern Tamilnadu district of Tirunelveli.  The agitation against this nuclear plant started way back 1989 but due to various reasons like the disintegration of Soviet Union into several states and the change of the Government in India the work on these reactors could not be commenced earlier.  Subsequently the conditions of the agreement changed between India and the aid lending Soviet state after about a decade even the Union Government chose to continue to give life to the first environmental clearance given in 1988-89 so that its lease of life prolonged although under usual circumstances the validity of environmental clearance is only for 5 years for all industrial projects.  The reports of the site selection committee and the environmental impact appraisal reports given by experts and the nuclear power project authorities were based on insufficient and improper data even by violating international standards on nuclear safety.  The public were informed and they never involved in the preparation of the emergency preparedness plans and in chalking out evacuation schemes to protect public health and the environment in the case of a maximum credible accident like the one which occurred at Fukushima in Japan in March 2011 due to human failures.  The public demands to make available the environmental Impact Assessment reports including the Emergency Preparedness Reports were not given to the public who requested them for the same and they were slowly coming out due to applications made by the environmental activists under the Right to Information Act.  Even without making a scientific based mock drill for emergency preparedness and disaster management consequent to a potential nuclear reactor explosion the authorities are misleading both the public, the state and central Government authorities on the safety of nuclear power even by violating the environmental protection rules and regulations and the guidelines issued by the national Disaster Management Authority under the Chairmanship of the Prime Minister on the disaster management procedures to be followed for handling the consequences of a radiological emergency arising from nuclear power plants.  In order to provide some basic idea about what kinds of emergency preparedness plans have been made for several reactors in several countries of the world are presented below so that a comparison can be made on the measures being taken by the state and central governments and nuclear power authorities for ensuring the safety of the people and their environment in case of the Kudankulam nuclear power plant.  It is proposed to revise this presentation in the near future after receipt of construction suggestions from the concerned people. 

 
1]UNITED STATES

Emergency Planning Zones for nuclear accidents as per United States Standards (80kms Zone):
 http://www.nrc.gov/about-nrc/emerg-preparedness/about-emerg-preparedness/planning-zones.html

To facilitate a preplanned strategy for protective actions during an emergency, there are two emergency planning zones (EPZs) around each nuclear power plant. The exact size and shape of each EPZ is a result of detailed planning which includes consideration of the specific conditions at each site, unique geographical features of the area, and demographic information. This preplanned strategy for an EPZ provides a substantial basis to support activity beyond the planning zone in the extremely unlikely event it would be needed.

The two EPZs are described as follows:

Plume Exposure Pathway EPZ

The plume exposure pathway EPZ has a radius of about 10 miles from the reactor site. Predetermined protective action plans are in place for this EPZ and are designed to avoid or reduce dose from potential exposure of radioactive materials. These actions include sheltering, evacuation, and the use of potassium iodide where appropriate. For more information, see Typical 10-Mile Plume Exposure Pathway EPZ Map.

Ingestion Exposure Pathway EPZ

The ingestion exposure pathway EPZ has a radius of about 50 miles from the reactor site. Predetermined protective action plans are in place for this EPZ and are designed to avoid or reduce dose from potential ingestion of radioactive materials. These actions include a ban of contaminated food and water.

http://www.nrc.gov/about-nrc/emerg-preparedness/about-emerg-preparedness/planning-zones.html

2]JAPAN:

http://www.asiadailywire.com/2012/09/japan-expands-nuclear-disaster-management-zones/ 

According to The Nikkei, disaster management zones will cover a distance of up to 30km from nuclear power reactors. In cases of accidents, areas within 5km will be considered ‘immediate evacuation zones’ while areas up to 30km away will be designated as ‘probable evacuation zones’. The current zones only reach as far as 8-10km. The new established regulatory authority also urged emergency centers for disaster response set up by central and local governments be located further away. Under the new guidelines, idle reactors will only be restarted if local governments are well-prepared for accidents, as approved by the regulatory.

3] INDIAN STANDARDS:
The AERB Code of Practice on Safety in Nuclear Power Plant Siting lays down desirable criteria for population for selection of a site as follows:
“Other desirable population distribution characteristics in plain terrain are:
i) Population centers greater than 10000 should not be within 10 km of the plant.
ii) The population density within a radius of 10 km of the plant should be less than 2/3 of the state average.
iii) There should be no population centres more than 100000 within 30 km from the plant.
iv) The total population in the sterilised area should be small, preferablyless than 20000.”
It may be reiterated that these are only desirable criteria and are prescribed to enable easy emergency planning.
For the purpose of planning for serious accidents, if any, an area of 16 km around the plant is considered as the Emergency Planning Zone. The AERB Code of Practice on Safety in Nuclear Power Plant Siting states:
During emergency, availability of transportation network means of communication, etc. which are of significance during emergency condition shall be checked. A radial distance of 16 km from the plant may be considered for this purpose.

http://www.npcil.nic.in/pdf/news_28sep2011_02.pdf

The AERB Code of Practice on Safety in Nuclear Power Plant Siting states: An exclusion area of appropriate size (at least 1.5 km radius from the reactor centre) shall be established around the reactor and entry to this is to be restricted to authorized personnel only. Thus the population falling within the exclusion zone, if any, is only resettled. The sterilized zone is the annulus between the exclusion zone and an area up to 5 km from the plant. The AERB code states in this regard:

“A sterilised area up to 5 km around the plant shall be established by administrative measures where the growth of population will be restricted for effective implementation of emergency measures. Natural growth, however, is allowed in this zone”. Thus, there is no displacement involved in the sterilized zone.

In fact, there are no restrictions on natural growth of population in the sterilized zone. The administrative measures are put in place to ensure that there is no large increase in the population due to say setting up of an industry involving large labour force, etc. 

http://www.npcil.nic.in/pdf/news_28sep2011_02.pdf 

 (From NPCIL publication on Frequently Asked Questions on Kudankulam Nuclear Power Project)

 EMERGENCY PLANNING ZONES:  NUCLEAR ACCIDENTS, IAEA

www-pub.iaea.org/mtcd/publications/pdf/method2003_web.pdf  [see Page.91] 

http://publications.jrc.ec.europa.eu/repository/bitstream/111111111/2756/1/reqno_jrc43311_final%20version%5B2%5D.pdf 

http://publications.jrc.ec.europa.eu/repository/bitstream/111111111/2756/1/reqno_jrc43311_final%20version%5B2%5D.pdf

The document [4] requires that for facilities in threat category I or II,arrangements shall be made for effectively making and implementing decisions on urgent protective actions to be taken off the site within:

(a) a PAZ, for facilities in threat category I, within which arrangements shall be made with the goal of taking precautionary urgent protective action, before a release of radioactive material occurs or shortly after a release of radioactive material begins, on the basis of conditions at the facility (such as the emergency classification) in order to reduce substantially the risk of severe deterministic effects.

(b) an UPZ, for facilities in threat category I or II, within which arrangements shall be made for urgent protective action to be taken promptly, in accordance either with international or national standards, in order to avert dose off the site.

The PAZ and UPZ should be roughly circular areas around the facility, their boundaries should be defined, where appropriate, by local landmarks (e.g. roads or rivers) to allow easy identification during a response as illustrated in Fig. 4.1. It is important to note that the zones should not stop at national borders. The size of the PAZ and the UPZ should be consistent with the guidance provided in Appendix II of [5].

(c) In addition to PAZ and UPZ, there is also a Food Restriction Planning Zone(FRPZ), which is more often called Longer-term Protective action Zone (LPZ).

This is an area around the facility where preparations for effective implementation of protective actions to reduce the long term dose, i.e. the risk of stochastic health effects5 from deposition and ingestion of locally grown food, should be developed in advance. The longer term protective action zone will of course include the PAZ and the UPZ and extend to a further radius. On the bases of severe accident studies, the United States Nuclear Regulatory Commission (USNRC) for instance has adopted this zone of 80 km (50 miles), however, it might be much larger, up to a couple of hundreds of kilometres.

  On-Site: Internal zone, under control of NPP operator

PAZ: Precautionary Action Zone            UPZ: Urgent Protective action planning Zone

LPZ: Long-term Protective Zone (Food Restriction Planning Zone-FRPZ)

[12]. The calculations assumed average meteorological conditions, no rain, ground level release; 48 hours of exposure to ground shine, and calculates the centralized dose to a person outside for 48 hours. The suggested sizes for the PAZ were based on expert judgment considering the following:

http://www-pub.iaea.org/MTCD/Publications/PDF/Method2003_web.pdf

 UK

 TABLE4 SHORT TERM EFFECTS OF EXPOSURE ON POPULATION HEALTH AND THE EFFECTS OF EMERGENCY COUNTERMEASURES: FOUR EXAMPLES OF SELECTED SCENARIOS ⁽¹⁾

Release type	Weather conditions	Wind direc-tion	No. of early deaths	No. of prodomal vomiting (2)	Area evacuated (sq.km)	Max. distance (A)	people evacua-ted (B)	shelter- Area (3) (C )	persons sheltered  (3) (D)
UK1	FD	270O	725	2,300	255	35	22,000	820	205,000
Uk1c	D5	240O	0	2	17.5	8.6	5,350	325	155,000
Uk9	DR	210O	0	0	12.5	5	1,100	23	3,200
UK11	D5	240O	0	0	13	5	4,750	13	4,750

A)     Max. distance of evacuation(km)

B)      No. of people evacuated

C)      Area of sheltering using NRPB’s ERL-2 criteria

D)     Total No. of persons sheltering using NRPB’s ERL-2 criteria

(1): Results for all 36 scenarios can be found in Appendix1, Tables 3 and 5.  Criteria for countermeasures described in Table 4.

(2)  Not estimated by NRPB; evaluated by using the ratio between early deaths and prodomal vomiting in each type of release in NRPB –R137.  The number of people suffering from prodomal vomiting includes those who will die.  Figures are estimated after taking into account counter-measures implementation.

(3) Includes the number of people or area which will be evacuated some hours afterwards (shown in above columns 8 and 6) as well as those people or areas for which no evacuation will take place but for which the exposure dose is within the range defined in NRPB’s ERLs for sheltering.  The latter group taking shelter are not considered in estimating early health effects.

KUDANKULAM

CONSEQUENCES OF RADIOACTIVE RELEASES FROM KUDANKULAM NUCLEAR STATION ON THE POPULATION:

 Main results of the countermeasures scenario, using the MARC model

( For weather conditions referred to the table presented below)

                                                       TYPE OF ACCIDENT: UK1              

Wind direction (Southern winds with slight variation on either side)		Weather Conditions: DR   240o
1. Consequences of emergency counter-measures - Potential Sheltering1:    Surface area2 Maximum distance from reactor Population concerned	Sq.km Km Persons	3,000 170 30,00,000
- Evacuation:  :   Surface area Maximum distance from reactor Population concerned	Sq.km Km Persons	800 85 15,00,000
2. Consequences of emergency counter-measures - Relocation of population prior to decontamination: Surface area Maximum distance from reactor Population concerned	Sq.km Km Persons	2,000 115 20,00,000
Decontaminated area still not re-inhabited after 5 years : Surface area Maximum distance from reactor Population concerned	Sq.km Km Persons	1,500 115 500,000
Decontaminated area still not re-inhabited after 20  years : Surface area Maximum distance from reactor Population concerned	Sq.km Km Persons	700 80 10,00,000
3. Health effects – as estimated by NRPB3:    - early  deaths - late deaths (cancer)		3,000 50,000

(Approximate values have been presented due to non-availability of latest population data)

NOTES FOR TABLE 3:   1. This ‘potential sheltering’ corresponds to the application of NRPB countermeasures recommendations in ERL-2.  In the calculation of health consequences, sheltering is considered only in the evacuation area, prior to evacuation. 2. ‘Surface areas’ in this Table are land areas only.  3.  These health effects have been  computed by the NRPB considering only evacuation as a counter-measure.  Sheltering is assumed to be required only for evacuated people, prior to evacuation.  No specific relocation model is used, but it is assumed that source after evacuation (this implicitly corresponds, relocation).  

METEOROLOGICAL CONDITIONS USED IN ESTABLISHING THE ACCIDENT SCENARIOS

Code Name	Atmospheric stability	Duration (h)	Pasquill category	Windspeed1 (m s-1)	Mixing layer depth1(m)	Rainfall rate (mm h-1)
D5	Neutral	Total	D	5	800	0
FD	Stable	t < 4 h t > 4 h	F D	2 5	100 800	0 0
DR	Neutral (Rain)	Total	D	5	800	1.0

Note:  The Values assigned to the wind speed and mixing  layer depth are representatives values for the corresponding Pasquill stability categories and have been taken from: R.H Clarke, ‘The First Report of a Working Group on Atmospheric Dispersion:  A model for short and medium range dispersion of radio nuclides released to the atmosphere’, NRPB, Harwell, NRPB-R91, 1979.  Pasquill categories are used to classify the degree of stability of weather conditions in order to distinguish the main atmospheric dispersion patterns of clouds emitted from land-based source.

RISK ANALYSIS OF KUDANKULAM REACTOR ACCIDENT : REMEDIAL MEASURES SCENARIO FOR TAMILNADU STATE

(Due to the reactor accident at Kudankulam  the following villages and towns will be facing the risks of poisonous radioactive pollution)

Distance from reactor	Time taken to execute counter measures		Places effected due to UK1/DR/240 (For weather conditions see table above with the modification that  the wind direction is taken as South )
	Sheltering	Evacuation
0 - 5 km	1 hr	2 hr	Ponnarkulam, Erukkandurai, Nakkaneri, Panaivilai, Sanganeri, Vairavikinaru, Idintakarai, ThilaivaranThoppu, Kudankulam
5  - 30 km Zone-A	6 hr	12 hr	Nagercoil, Marungoor, Anjugramam, Aralvaimozhi, Ramapuram, Therur, Rajavoor, Shankaranputhoor, Vadasery, Thirupattisaram, Vellamadam, Kothaigrammam
30 - 85 km (20 years) Zone-A	6 hr	1 day	Kayathar, Ithikulam, Paneerkulam, Thalayalnadanthankulam, Ayyanaruthu, Nellai, Kandheeswarampudur, Pallikottai, Alavanthankulam, Thenkalam Pudur, Periyarnagar, Thathanuthu, Thalaiyuthu, Senthimangalam, Thachanallur, Balabagyanagar, Tirunelveli, Vanarapettai, Palayamkottai, Naranammalapuram, Kattudayar, Kudiyiruppa, Kurichikulam, Vengadasalapuram, Kollankinar, Maniyachi, Gangaikondan, Savalaperi, Rayavallipuram, Melapattam, Burkitmangaram, Reddiarpatti, Sivanthipatti, Panayankulam, Maruthakulam, Caussanelpuram, Perinbapuram, Kandinthakulam, Tharuvai, Keeloomanallur, Pannankulam, Nellaiyappapuram, Mulaikkaraipatti
85– 110 km (10 years) Zone-B	6 hr	2 days	Akhilandapuram, Sivagnanpuram, Chettikurichi, Naickerpatti, Kattalankulam, Kalampatti, Sayamalai Madhuthupatti, Kokkukulam, Karadikulam, K.Velayuthapuram, Meenthulli, Valikandapuram, Kalugumalai, Vanaramutti, Alangulam, Zamin Devarakulam, Vagaikulam, Alaganer, Azhakunachiapuram, Maruthankinaru,
110 – 140 km          (5 Years) Zone-C	6 hr	2 days	Srivilliputtur, Sivakasi, Sattur, Rajapalayam, Poolavoorani, Madathupatti, Samsigapuram, Thenmalai, Mamsapuram, Ayyaneri, Venkatachalapuram, Ilayarasanendal, Elayiramapanni, Thiruvengadam, Melachthiram, Sankaramurthipatti, Viswanadham, Meenampatti, Vadamalapuram, Anaikuttam, Thiruthangal, Thlukankulam.
140- 170 km and above (1 Year) Zone-D	6 hr	2 days	Peraiyur, Vannivelampatti, Villur, Thaaniparai, Watrap, Kallikudi, Sengapadi, Virudnagar, Kumapatti, Mangalam, Amathur, Maharajapuram, Ayankarisalkuam, Kilankualm vandapuli, Mallapuram,Karaikeni, Solaipatti, Maravankulam, Usilampatti, Madurai.

 The details given above are approximate because the relevant detailed maps are not available with the author and they will be improved as soon as more details are received.

Note: Intervals between evacuation and reoccupation of original houses and lands after decontamination

Since the radio-active pollutants seriously pollute the lands, buildings and equipment, the people duly evacuated and rehabilitated in safer places, can return along with their cattle to their original homes in their native places only

1) after one year upto 170km and above from the reactor

2) after 5 years upto 135km from the reactor

3) after 10years upto  120km from the reactor and

4) after 20 years upto 80km from the reactor. 

Depending upon the vagaries of the weather, some places may be more polluted than others.

 

DEFENCE IN DEPTH

http://www-ns.iaea.org/downloads/ni/training/TCS-15_web.pdf

http://www-pub.iaea.org/MTCD/publications/PDF/P082_scr.pdf

 

http://nidm.gov.in/PDF/guidelines/nuclear_radiological_emergencies.pdf 

For animation purposes see website to see the nuclear plant in working condition 

http://www.nrc.gov/reading-rm/basic-ref/students/animated-pwr.html

http://nidm.gov.in/PDF/guidelines/nuclear_radiological_emergencies.pdf

 

1. US ENVIRONMENTAL AGENCY PREDICTIONS ON DISASTERS BASED ON FUKUSHIMA ACCIDENT  

For detailed narrative see website: http://www.nrdc.org/nuclear/fallout/

 http://www.nrdc.org/nuclear/fallout/

 http://www.nrdc.org/nuclear/fallout/

 http://www.nrdc.org/nuclear/fallout/

 

2.  PUBLIC AGITATION AGAINST  INDIANA POINT REACTOR,NEW YORK, DISASTER SCENARIO
For more detailed information on the predicted nuclear reactor explosion and its impacts see website:
http://www.nrdc.org/nuclear/indianpoint/files/NRDC-1336_Indian_Point_FSr8medium.pdf 

3.   PREDICTED AND OBSERVED RADIOACTIVITY LEVELS DUE TO CHERNOBYL ACCIDENT 1986

 http://ec.europa.eu/energy/nuclear/radioprotection/doc/studies/emergency_planning_en.pdf

Table 5 gives the most important emissions due to the accident. The released fractions correspond with the theoretical predictions of the source term in case of an early failure of the containment of a PWR reactor.

Nuclides	Released fraction (% of the core inventory)	Released activity (PBq)
Xe-133	100	6 500
I-131	55	1 800
Cs-137	33	85
Cs-134	33	52
Sr-90	4	8
Pu-239	3.5	3 10-2

Table 5 : Most important emissions due to the Chernobyl accident.

The emission was composed of core fragments, fine aerosols and volatile fission products (gas and condensation aerosols). Hot particles, or core fragments (UO2), or graphite fragments contaminated with condensed semi-volatile fission products were found.

The high temperature of the releases led to a significant increase of the effective height of the radioactive cloud (up to around 1 000 m). This led to transport of radioactivity over very large distances.

The main exposure routes were, in chronological order: exposure to direct irradiation from the cloud, inhalation of iodine and irradiation of the soil and other contaminated surfaces (5 to 10 mSv/h at Pripyat). The latter factor constituted the basis of the decision for evacuating an area of 30 km around the power plant. During several days, the cloud spread out over Europe and over the Northern Hemisphere. The deposition of iodine and caesium and also the resulting contamination of food products were considered as being the chief issues.

The countermeasures may be summarised as following [3]:

• evacuation of about 110 000 persons during the first month;

• distribution of stable iodine to several millions of persons;

• evacuation of several tens of thousands of animals;

• prohibition of consuming milk and fresh vegetables in a large part of Europe;

• construction of barriers to avoid transfer of the contamination to drinking water sources;

• decontamination and demolition of houses over a surface of 7 000 km²;

• decontamination of roads, treatment of fields, etc;

• delayed evacuation of 220 000 persons from their villages up to several hundreds of kilometres from the power plant, considering a potential chronic exposure of more than 5 mSv/y (in particular the villages contaminated by wet deposition).

 http://books.google.co.in/books?id=LItzN3tYwBIC&pg=PA205&lpg=PA205&dq=%22Figure+5.28+shows+the+distribution+of+radiation+levels%22&source=bl&ots=JhiRndd461&sig=lN8bmB0i4pAej1Xl_IZMsTvSUXs&hl=en&sa=X&ei=p5iCUJLjLJCzrAfj_IDYDg&ved=0CB0Q6AEwAA#v=onepage&q=%22Figure%205.28%20shows%20the%20distribution%20of%20radiation%20levels%22&f=true 

 4. US GOVERNMENT EVACUATED VICTIMS UPTO 32Km (20 MILES) FOR REACTOR ACCIDENT AT THREE MILE ISLAND IN UNITED STATES BASED UPON ACTUAL OBSERVATIONS OF RADIOACTIVITY WHICH STOOD ABOVE THE PERMISSIBLE LEVELS TO ENSURE PUBLIC SAFETY

For more details on the reactor accident and disaster management see the website below:

http://desastres.unanleon.edu.ni/pdf/2003/agosto/PDF/ENG/DOC540/doc540-contenido.pdf 

1000 MW NUCLEAR PLANT - DISASTER SCENARIO(350Km)

http://www.teachpeace.com/Catastrophic%20Releases%20of%20Radioactivity.pdf

DISASTER SCENARIO -1000 MW NUCLEAR PLANT SUBJECTED TO 

NUCLEAR BOMBING (1350 Km)

5. ACTUAL ISODOSE MAPS OF RADIOACTIVITY DUE TO FUKUSHIMA REACTOR EXPLOSION 

For more detailed information see the following website

http://hps.org/documents/IRSN_Fukushima_Report.pdf

 

  
Note: The following information is extracted in public interest from the NEI website cited below.

UNSAFE ASPECTS OF NEW RUSSIAN REACTORS (VVER 1000) AS PER ASSESSMENT OF EXPERTS

http://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/sourcebooksovietdesignednuclearpowerplants/

Third-Generation VVER-1000 (Nuclear Reactors under construction at Kudankuylam)

The VVER-1000 design was developed between 1975 and 1985 based on the requirements of a new Soviet nuclear standard that incorporated some   international practices, particularly in the area of plant safety. The VVER- 1000 design was intended to be used for many plants, and 18 units now operate in two former Soviet republics. Of these, two—Novovoronezh 5 andSouth Ukraine 1—are prototypes; three are Model V338s—Kalinin 1 and 2 and South Ukraine 2; and all the rest—Balakovo 1-4, Rovno 3, Khmelnitskiy 1, South Ukraine 3 and Zaporozhye 1-6—are Model V320s. Russia Balakovo 1-4 , Kalinin 1-2,Novovoronezh 5,Ukraine Rovno 3,Khmelnitskiy 1South Ukraine 1-3,Zaporozhye 1-6

Two VVER-1000 units were built outside the former Soviet Union:Bulgaria Kozloduy 5 and 6

VVER-1000 TYPE NUCLEAR PLANTS USED AT KUDANKULAM WERE STOPPED IN OTHER PLACES:

Work was stopped on two other VVER-1000 units in Bulgaria (Belene 1 and 2) after public protests over claims of unsuitable soil and seismic conditions.

The Hungarian government canceled Paks 5 and 6 in 1989.

Construction of two VVER-1000 units at Stendal, in the former East Germany, was halted following reunification with West Germany.

Two VVER-1000 units under construction at Temelin in the Czech Republic are being upgraded with Western instrumentation and control equipment and fuel.

A total of 25 VVER-1000 units are at some stage of construction in the former Soviet Union—15 in Russia and 10 in Ukraine. But work on 12 of these units in Russia, and six in Ukraine, has reportedly been canceled or deferred indefinitely.

Of the VVER-1000 units earmarked for completion under the 1992 Russian plan, Kalinin 3—originally scheduled to come on line in 1995—is expected to be operational by 2000, according to a Ministry of Atomic Energy official.

Other units expected to come on line by 2000 are Balakovo 5, a VVER-1000, and Rostov 1, a VVER-1000 that is reportedly 97 percent complete. A second unit at Rostov is said to be 95 percent complete, but there is local opposition to both projects. Russia’s new energy law requires the approval of local authorities for plant construction.

Ukraine is seeking funding to complete the construction of two VVER-1000 units—Khmelnitskiy 2 and Rovno 4.

Principal Strengths:

n Steel-lined, pre-stressed, large-volume concrete containment structure, similar in function to Western nuclear plants.

n “Evolutionary” design incorporating safety improvements over VVER-440 Model V213 plants. The Soviet approach to standardization was based on continued use of components that had performed well in earlier plants.

n Use of four coolant loops and horizontal steam generators—both considered improvements by Soviet designers.

n Redesigned fuel assemblies that allow better flow of coolant, and improved control rods.

n Plant worker radiation levels reportedly lower than in many Western plants, apparently due to selection of materials, high-capacity system for purifying primary coolant, and water chemistry control.

DEFECTIVE SAFETY ASPECTS OF VVER-1000 REACTORS PROPOSED AT KUDANKULAM

Principal Deficiencies:

n Substandard plant instrumentation and controls. Wiring of emergency electrical system and reactor protection system does not meet Western standards for separation—control and safety functions are interconnected in ways that may allow failure of a control system to prevent operation of a safety system.

n Fire protection systems that do not appear to differ substantially from earlier VVER models, which do not meet Western standards.

n Quality control, design and construction significantly deficient by U.S. standards.

n Protection measures for control-room operators essentially unchanged from earlier VVER-440 Model V213 design, which does not meet U.S. standards. Unlike all U.S. nuclear plants, and most in Western countries, VVER-1000s have no on-site “technical support center” to serve as a command post for stabilizing the plant in an emergency. Technical support centers were incorporated in U.S. and many Western nuclear plants following the accident at Three Mile Island Unit 2 in 1979.

n Operating and emergency procedures that fall far short of Western standards and vary greatly among operators of VVER-1000 plants.

n Higher power densities and the smaller volume of primary and secondary systems result in a somewhat less forgiving and stable reactor.

VVER-1000 Derivatives

Even before the breakup of the Soviet Union, derivative versions of the VVER-1000 were under development.

In 1987, design work was begun on the VVER-1800, a VVER-1000 upgraded for greater safety and economy. The VVER-1800 design incorporated a lower-power reactor core, annual refueling, and more reliable control and protection systems.

In 1989, Finland and the Soviet Union jointly announced the start of development work on the VVER-91, a VVER-1000 version that would meet stringent Finnish nuclear plant design requirements. On paper, the Soviet VVER-91 design is among the world’s most advanced light water nuclear power plants.

Development of a new VVER-1000 design, the VVER-92, was expected to be carried out with Western assistance. The VVER-92 incorporated what one Finnish nuclear expert called “radically simplified” plant systems that included active safety systems, a reduced-power reactor core, and a double containment structure surrounding the nuclear reactor. However, the Ministry of Atomic Energy has reportedly diverted some funding for VVER-

92 development to a pilot project for building a smaller advanced VVER, the VVER-640 or Model V407.

 

Classifying Nuclear Events with the INES

Had the INES existed at the time, these nuclear events would have been classified as follows:

Chernobyl. The 1986 accident in Ukraine involved wide environmental and health effects and would have been classified as a Level 7 “Major Accident.”

Three Mile Island. The 1979 accident that seriously damaged the core of Unit 2 at this nuclear power plant in Pennsylvania involved the release of very small amounts of radioactivity outside the plant and would have been classified a Level 5 “Accident With Off-Site Risks.

” VVER-1000 Program on Safety

In February 1992, the IAEA was asked to expand its safety program on the VVER-440 Model 230 reactors to other Soviet designs. Bulgaria, Czechoslovakia and Ukraine separately requested that the agency initiate a more comprehensive safety evaluation of VVER-1000 nuclear power plants. The VVER-1000 is a design that shares similarities with Western plants, in terms of design philosophy, design features and constructability. However, concerns remain about engineering design solutions, quality of manufacture, and reliability of equipment. The strategy for improving the safety of VVER-1000s is similar to the IAEA’s plan to upgrade the VVER-440 Model V213s. The main elements of the VVER-1000 program follow.

Steam Generator Collector Integrity

Between 1986 and 1991, 24 VVER-1000 steam generators developed cracks in primary cold collectors; cracking occurred after 7,000-60,000 hours of operation, and was determined to be caused by environmentally assisted cracking at temperatures of about 280 degrees C. Although cracked collectors were generally replaced, and the cause identified, concern remains:

As of November 1993, 19 operating VVER-1000s had been outfitted with 76 of the steam generators in question.

The rupture of steam generator collectors could initiate accidents of high safety significance in two ways: The radioactive primary coolant could be discharged to the environment through the main steam atmospheric dump; and the long-term cooling of the core cannot be assured in the event of loss of primary coolant water through the main steam atmospheric dump. In addition to the existing corrective measures, the IAEA has suggested improvements related to detection, inspection, repair, material, manufacturing processes, stress relieving, accident mitigation, and operating conditions. A new, improved steam generator design is under consideration at Gidropress, a Russian nuclear components manufacturer. The following are other important future activities:

n All adopted measures should ensure a low probability of a catastrophic break of the collectors.

n The current estimates of the safety consequences of a steam generator rupture accident should be reviewed, with the aim of developing preventive and mitigative accident management procedures.

n In the short term, preference should be given to upgrading the main steam atmospheric dump valves for discharging of steam-water mixture and to developing procedures for better maintaining the water inventory.

Fuel Assembly Structural Instability

Deformed fuel assemblies were discovered at Balakovo and Zaporozhye 1. The problem was observed after an irradiation of two years in the core. In addition, the distance between spacer grids was no longer uniform. Preliminary results of a post-irradiation examinations by Russia’s Scientific Research Institute of Nuclear Plant Operations confirmed the deformation of whole fuel assemblies; the institute continued its study in 1994, and is looking into whether the cause is a design problem. The spacer grid movement may be the result of inadequate loading.

While a root cause analysis is under way, design modifications to make the fuel assembly structure more rigid and to provide dimensional stability are being considered by the Russian designer.

Control Rod Insertion Reliability

During the refueling of Zaporozhye 1 in late 1992, it was discovered that eight control rod assemblies were not at the bottom position. Subsequently, the same problem was seen at Balakovo, Kalinin, Khmelnitskiy, Rovno and South Ukraine. In addition, an increased drop time exceeding the maximum design value was observed. Most of the problems have occurred during the third year of operating an assembly in the reactor.

Root cause investigations are being conducted. A preliminary conclusion links the problem to an increase in the friction between the control rods and their guide tubes in the fuel assemblies due to shape changes of the guide tubes or possible rubbed surface roughness. There appears to be a close correlation between the control rod insertion problem and the structural instability of fuel assemblies.

While the IAEA stresses the importance of determining the root cause and implementing measures to eliminate the problem, the agency notes that the final solution may rest on the new improved design of fuel and control assemblies.