ML20234C912

Affidavit of Ps Littlefield.* Discusses Analysis of Steam Generator Tube Rupture for Plant at Full Power.Related Info Encl

ML20234C912
Person / Time
Site:	Seabrook
Issue date:	12/23/1987
From:	Littlefield P YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML20234C672	List: ML20234C670 ML20234C720 ML20234C827 ML20234C848 ML20234C869 ML20234C872 ML20234C894 ML20234C912 ML20234C996 ML20234D014
References
OL-1, NUDOCS 8801060370
Download: ML20234C912 (7)

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UNITED STATES OF AMERICA j UNITED STATES NUCLEAR REGULATORY COMMISSION 4 before the ATOMIC SAFETY AND LICENSING BOARD

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In the Matter of )

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PUBLIC SERVICE COMPANY ) Docket Nos. 50-443 OL-1 NEW HAMPSHIRE, et al. ) 50-444 OL-1

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(Seabrook Station, Units 1 ) (On-site Emergency and 2) ) Planning 103ues)

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AFFIDAVIT OF PETER S. LITTLEFIELD I, PETER S. LITTLEFIELD, being on oath, depose and say as follows:

1. I am employed by Yankee Atomic Electric Company as Manager of the Radiological Engineering Group. A statement of my professional qualifications is attached hereto and marked as Attachment "A".

2. The Steam Generator Tube Rupture (SGTR) is one of a number of design basis accidents that is analyzed prior to operation of a nuclear power station. The analysis of this accident for the Seabrook Station at full power operation is found in Section 15.6 of the FSAR. The critical thermal hydraulic and radiological assumptions made in the FSAR

-include the following:

a. The total' mass of reactor coolant transferred to the secondary side of the ruptured steam generator prior to pressure equalization is 101,000 lbs.

b. Seventeen percent of the reactor coolant transferred to the secondary side flashes to steam.

All'of the radioactive iodine in this flashing fraction is released immediately to the environment.

c. A preexisting spike has occurred which has raised i

8801060370 880104 PDR ADDCK 05000443 G PDR

4 the dose equivalents I-131 concentration of the reactor coolant to the technical specification limit of 60 uCi/gm.

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3. The only significant radiological effect of the SGTR is the thyroid dose produced by the release of radiciodine.

j The FSAR analysis resulted in a thyroid dose of 66 rem at the exclusion area boundary. The design limit as specified by 10 CFR 100 is 300 rem. The whole body dose reported in the FSAR for this accident is only 120 mrem (0.12 rem) and is therefore of little concern from the standpoint of public health risk and emergency planning.

4. The FSAR also analyzes the SGTR for an iodine spike that occurs coincidentally with the tube rupture. This event, however, produces lower radiation doses than the preexisting spike case described above.

5. Operation of the plant during low power testing (up to 5% of rated power for several days) results in substantially decreasing the potential consequences of design basis accidents. The impact of this low power operation on the FSAR SGTR assumptions is discussed below.

6. The mass of reactor coolant that could be transferred to the secondary side increases at low power at a result of density changes, reactor trip timing and other thermal hydraulic considerations. A conservative analysis of this mass flow at low power has resulted in an upper bound estimate of 140,000 lbs. (Affidavit of Ping Huang on Mass Transfer and Flashing Fraction for a Steam Generator Tube Rupture at 5 Percent Power.) This would increase the thyroid dose by approximately 40%.

7. The reactor coolant entering the steam generator is at a lower temperature during low power operation (approximately 70' F lower), and therefore the flashing fraction of this coolant in the secondary side is reduced to less than 7.5 percent (Affidavit of Ping Huang on Mass Transfer and flashing Fraction for a Steam Generator Tube Repture at 5 Percent Power). This reduces the potential iodine release to the environment and results in reducing the thyroid dose by approximately a factor of 2.

8. The greatest impact of low power operation, however, is that the potential quantity of iodine available for 1 The dose equivalent I-131 concentration accounts for the other radioactive isotopes of iodine.

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release to the environment is significantly less. This is due to:

a. A reactor core iodine inventory of at least a factor of 20 less than full power operation.

b. A lower fuel gap iodine fraction available for release to the coolant due to low fuel burnup and low fuel temperature (USNRC 82).

c. A low potential for cladding failure during early core life.

9. A study has been completed of iodine concentration in reactor coolant during first fuel cycle operations (Affidavit of Kenneth Rubin on Reactor Coolant Activity at 5 Percent Power). The study included 35 nuclear power stations and over 100 individual measurements.

The reactor coolant results are shown below:

I-131 Concentration, uCi/gm Normalized Corrected to 100% Dower 5% Dower Maximum 0.065 0.00325 Average 0.0043 0.00022 Minimum 0.00006 < 0. 00001

10. A second study of iodine spiking source terms for accident analysis has analyzed the characteristics of 70 iodine spikes in operating reactors (Lu 81). This study reported the equilibrium concentration prior to the start of the spike, and the peak concentration following the spike for each event. The highest reported ratio of peak-to-equilibrium concentrations was 170. If this maximum ratio is multiplied by the highest equilibrium reactor coolant concentration shown above, the result would be a bounding spike reactor coolant concentration of I-131 of 0.55 uCi/gm (170 x 0.00325 =0.55).

Accounting for the other isotopes of iodine results in a dose equivalent I-131 concentration of approximately 1.4 UCI/gm. This low preexisting spike concentration would reduce the thyroid dose by approximately a factor of 40.

11. The overall result of adjusting the critical assumptions discussed above for operation at 5% power is to produce an exclusion area boundary thyroid dose of approximately 1.1 rem. This should be considered a bounding value since conservative assumptions regarding mass transfer, coolant flashing, iodine concentration and spiking ratio have all been compounded. Based on this result, it is

concluded that SGTR events, during initial low power testing, produce an exceedingly small risk to the health and safety of the public, and require no offsite protective actions.

Pet 6r S. Littlefie/d COMMONWEALTH OF MASSACHUSETTS

, ss. December s23, 1987

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The above-subscribed Peter S. Littlefield appeared before me and made oath that he had read the foregoing affidavit and that the statements therein are true to the best of his knowledge.

Before me,

$W Notary Public My Commision Expires:

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References 'l Lu 81 Lutz,.R.J., Jr., " Iodine and Cesium Spiking Source-Terms for Accident Analysis," WCAP 9964 (Proprietary Class 2), 1981.

i' USNRC 82 " Background and Derivation of ANS-5.4'.

Standard Fission Product Release Model,"

NUREG/CR-2507, 1982.

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4 PETER S. LITTLEFIED Mr. Littlefield received his Bachelor of Science Degree in Chemical Engineering from Northeastern University in 1962 and his Master of Science Degree in Radiation Biology from the University of Rochester in 1963. He completed the Health Physics training program sponsored by the U.S. AEC at Brookhaven National Laboratory in the summer of 1963.

Mr. Littlefield was employed by Brookhaven National Laboratory from 1963 to 1967 with a 2-year leave of absence to serve in the U.S. Army. While at Brookhaven, he worked in the Applied Research Section of the Health Physics Department on such projects as mixed field dosimetry, linear energy transfer analysis and low-level radioactive gas monitoring.

He co-authored a paper on the continuous environmental monitoring of noble gases and currently holds a patent on a high pressure monitor associated with this project.

In 1967 Mr. Littlefield joined the General Dynamics Corp., Quincy, Massachusetts as a Radiological Engineer. He became the Health Physics Supervisor in 1967. In that j position, Mr. Littlefield was responsible for 8 health physics technicians and for providing continuous health physics coverage to the shipyard. He was also the shield survey engineer on 2 new construction nuclear submarines. As such, he was responsible for the training of the shield survey, the evaluation of the data and the preparation of the final report on the acceptability of the nuclear shielding.

In 1968 Mr. Littlefield joined Yankee Atomic Electric Company as a Safety Analysis Engineer in the Nuclear Services Division. In this position, he was responsible for the analysis of engineered safety systems intended to mitigate the release of fission products foolowing an accident, and for the analysis of primary coolant leakage detection systems and post accident hydrogen control systems. He was also responsible for preparing safety analysis report sections dealing with process radiation monitoring radioactive waste processing, accident analysis and environmental monitoring.

In 1973 Mr. Littlefield was appointed Manager of the Radiological Engineering Group at Yankee with responsibilities for radiological dose analyses, radiation environmental surveillance, meteorological monitoring, radioactive waste processing, and special siting studies. He is also responsible for performing design basis accident radiological analyses and consequence analyses in support of probabalistic risk assessments. He is currently carrying out these responsibilities for 3 operating nuclear power stations (2 PWR, 1 BWR) and 1 PWR under construction.

-A-

Mr. Littlefield is a member of the Health Physics Society and have served in sever al offices, including President, of the New England Chapter of this Society. He was certified in Health Physics by the American Board of Health Physics in 1977.

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