ML20066A860

Forwards Calculations of Clad Oxidation for 1100 F Re Effects of Pump Seizure Transient on Fuel Integrity. Calculations Amplify 820414 & 0625 Submittals.No Fuel Damage Will Result at Calculated Condition

ML20066A860
Person / Time
Site:	Midland
Issue date:	11/01/1982
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Harold Denton Office of Nuclear Reactor Regulation
References
19390, NUDOCS 8211060249
Download: ML20066A860 (4)

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ConsumEIS Power James W Cook Vice President - Projects, Engineering and Construction Generel offices: 1945 West Parnell Roed, Jechoon, MI 49201 + L517) 788 0453 November 1, 1982 Harold R Denton, Director Office of Nuclear Reactor Regulation Division of Licensing US Nuclear Regulatory Commission Washington, DC 20555 MIDLAND NUCLEAR C0 GENERATION PLANT MIDLAND DOCKET NOS 50-329, 50-330 EFFECT OF PUMP SEIZURE TRANSIENT ON FUEL INTEGRITY FILE: 0505.16 SERIAL: 19390

References:

(1) J W Cook to H R Denton, CP Co Serial 16627 date.1 April 14, 1982.

(2) R L Tedesco to J W Cook dated June 25, 1982 (3) J W Cook to H R Denton, CP Co Serial 18809 dated September 1, 1982 (4) " Evaluation Models of Zircaloy Oxidation in Light of Recent Experiments" H Ocken, et al, from Zirconium in the Nuclear Industry, ASTM STP 681 (1979)

Enclosure (1) Calculation of Clad Oxidation for 1100*F Reference (1) provided information concerning fuel in DNB for the reactor coolant sump seizure analysis. The conclusion drawn from that analysis was that the calculated cladding temperature was sufficiently low as to preclude cladding failure even with 27% of the fuel pins calculated to have a DNBR less than the acceptance criterion. In response to Reference (2), a very conservative bounding analysis was performed assuming that the fuel in DNB failed. The resulting offsite doses associated with this analysis were calculated by CP Co to meet the acceptance criteria.

Based on subsequent discussions with the Staff reviewer, we submit the following in order to amplify the information given in Reference (1) and requested in Reference (2). Again, our conclusion is that this transient does not result in fuel damage since the calculated peak cladding temperature is low and time at temperature is short.

The fuel analysis for the pump seizure accident in Chapter 15 of the Midland FSAR was performed with the RADAR computer code, which has been accepted by the NRC (BAW-10069A). The code calculated a peak cladding temperature after 8211060249 821101 PDR ADOCK 05000329 A PDR oc1082-1364a131 k

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2 DNB of 1100 F and of short duration (FSAR Figure 15.3-11). During the transient, the coolant system remains pressurized, thus the cladding stresses that might be caused by a sudden depressurization are absent. As a result, fuel conditions are well below the criteria given in NUREG-0630 fm fuel swelling and rupture.

A review of the work conducted by 11 Ocken, et al, on Zircaloy oxidation vas performed (Reference 4). If we use the equation developed from WPI data shown on page 519 of the subject report, we arrive at clad corrosion of 0.4 nm for a one minute time period at 1100 F (Enclosure 1). To put this in perspective, this is the amount of clad corrosion that would occur at normal operating temperature over a four hour time period.

Thus we conclude that clad failure either by strain or oxidation is not a problem for the conditions calculated to exist for this accident.

JWC/JRW/fms CC RJCook, Midland Resident Inspector RHernan, US NRC WLJensen, US NRC Shih-Liang Wu, US NRC DBMiller, Midland Construction (3)

RWiluston, Washington oc1082-1364a131 f('

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_ _ . _ . _ _ - _ _ . . . ._ _ _ .. _ ___m Enclosure (1)

CALCULATION OF CLADDING OXIDATION t

Given rate constant equation (Ref 4, p 519):

Kp (mg/cm 2 )2/sec = 9.32 x 103 exp (-21,340/RT)

@ 645 K (700 F)

Kp = 5.068 x 10 -6 .

@ 866 K (1100 F)

Kp = 1.1724 x 10 _3 0xidation follows parabolic rate law

W = V Kpt ,

where W E reaction mass (mg/cm2 )

i Kp E rate constant ((mg/cm2 )2/sec) t E time (seconds)

@ 866 K for 60 seconds, i W = .265 mg/cm 2 using p 3 Zr

- 8/cm oxidation film thickness is W/p = .4 pm

@ 645 K, to achieve same thickness of oxidation film,

.265 mg/cm2=/5.068x10 -6 t t = 3.85 hrs t

oc1082-1364b131

CONSUMERS POWER COMPANY Midland Units 1 and 2 Docket No 50-329, 50-330 Letter Serial 19390 Dated November 1, 1982 At the request of the Commission and pursuant to the Atomic Energy Act of 1954, and the Energy Reorganization Act of 1974, as amended and the Commission's Rules and Regulations thereunder, Consumers Power Company submits information on fuel integrity after a pump seizure transient.

CONSUMERS POWER COMPANY By _

L J Cook, Vice President Pro' -ts, Engineering and Construction Sworn and subscribed before me this 1 day of November, 19.82 0 1-- -

m Notary Public Jackson County, Michigan My Commission Expires September 8,1984 i

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