ML20214E281

Proposed Tech Specs Re Reactor Pressure Vessel Neutron Fluence Projection

ML20214E281
Person / Time
Site:	Pilgrim
Issue date:	02/28/1986
From:	BOSTON EDISON CO.
To:
Shared Package
ML20214E276	List: BECO-85-024, Application for Amend to License DPR-35,consisting of Proposed Change 86-06,revising Tech Specs Re Reactor Pressure Vessel Neutron Fluence Projection.Fee Paid ML20214E281
References
NUDOCS 8603070242
Download: ML20214E281 (3)

Text

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FIGURE

3. 6.1 PILGRIM REACTOR VESSEL PRESSURE-TEMPERATURE LIMITS HYDROSTATIC AND LEAK TESTS si t

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RPV WALL l

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FLUENCE (dT) 400 8.0 2.8 x lo n/cm21 li I

2 l

l --- 10.0 3.4 x 10 n/cm i

I 200 t

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• PNPS EFFECTIVE FULL F0WER

~~~~~~-

YEARS (EFPY) AS OF 12/83

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END OF CYCLE 6 IS 6.68.

M.

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l 40 80 12 0 16 0 200 240 TE MPER ATURE

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AMENDMENT N O.

860307o242 e60228 12 8 PDR ADOCK 05000293 p

PDR

FIGURE 3.6.2 PILGRIM REACTOR VESSEL PRESSURE-TEMPERATURE LIMITS SUBCRITICAL/ CRITICAL HEAT UP & COOL DOWN RPV WALL 335'E FPY

• FLUENCE (dT)

III 8.0 2.8 x 10 n/cm I

2 r

1' 3 4

• IU

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1200 l

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0 40 80 120 16 0 200 240 TE M PER ATURE

(*F)

AMENDMENT N O.

128A

Bases:

3.6.A and 4.6.A Thermal and Pressurization Limitations (Cont'd)

The reactor coolant system is a primary barrier against the release of fission products to the environs.

In order to provide assurance that this barrier is maintained at a high degree of integrity, restrictions have been placed on the operating conditions to which it can be subjected.

Appendix G to 10CFR50 defines the temperature-pressurization restrictions for hydrostatic and leak tests, pressurization, and critical operation. These L

4 limits have been calculated for Pilgrim and are contained in Figures 3.6.1 and 3.6.2.

1 For Pilgrim pressure-temperature restrictions, two locations in the reactor i

vessel are limiting.

The closure region controls at lower pressures and the

]

beltline controls at higher pressures.

t The nil-ductility transition (NDT) temperature is defined as the temperature below which ferritic steel breaks in a brittle rather than ductile manner.

Radiation exposure from fast neutrons (>l mev) above about 10 nyt may shift the NDT temperature of the vessel metal above the initial value.

Impact tests from the first material surveillance capsule removed from the reactor vessel have established the magnitude of the RTuor shift for the beltline.

The shift, which is greatest for the weld metal, is tabulated below for various 1

i fluence levels:

RPV Wall 3

Fluence (1/4T)

RTuor 2.8 x 10 n/cm 61*F 2

i 3.4 x 10 n/cm' 68'F i

Neutron flux wires and samples of vessel material are installed in the reactor vessel adjacent to the vessel wall at the core midplane level.

The wires and samples will be periodically removed and tested to experimentally verify the l

values used for Figures 3.6.1 and 3.6.2.

The withdrawal schedule of Table i

4.6.3 has been established as required by 10CFR50, Appendix H.

l The pressure-temperature limitations of Figures 3.6.1 and 3.6.2 appilcable to i

the beltline reflect an initial RT=or of O'F.

This initial value is based f

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Amendment No.

139 l

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