ML20099D415

Proposed TS 3.6 Re LCO for Primary Sys Boundary & 4.6 Re Surveillance Requirements for Primary Sys Boundary

ML20099D415
Person / Time
Site:	Cooper
Issue date:	07/28/1992
From:	NEBRASKA PUBLIC POWER DISTRICT
To:
Shared Package
ML20099D413	List: ML20099D410 ML20099D415
References
NUDOCS 9208060009
Download: ML20099D415 (7)

Text

.

LIMITING CONDITIONS Pr)R OPERATION SURVEILIANCE PEOUIPEMENTS 376 Primary System Boufffry 4.6 Primary System Boundarv 6PDlic.a.111Ltn Atirelic abili ty :

Applies to the opnratin6 ctatus of Applics to the periodic exarnination the reactor coolant systern.

and testing requirements for the reactor cooling system.

Obiecti.yn Qhiectlyn To assure the intc6rity and safe To determine the condition of the 1

operation of the - reactor coolant reactor coolant system and the sys t ern,

operation of the safety devices related to it.

Specification:

Specification:

A.

Thermal and Pressurization A.

Therma) and Pressurization Limitatient Limitations 1.

The _ average rate of reactor coolant 1.

During heatups and cooldosas. the temperature change during normal following temperatures shall be heatup or cooldown shall not exceed permanently logged at least every 100'F/br whtn avtraged over a

15 minutes until the difference one hour perios..

between any two readings taken over a 45 minute period is less than 50*F.

a.

Bottom head drain.

b.

Recirculation loops A and B.

2, During operation where the core is 2.

Reactor vessel temperature end critical or during heatup by resctor coolant 1 pre ssure shall be nonnuclear _(means or couldown perm: nently logged at 1 cast every

-follouing --ahutdown, the reactor 15 minutes whenever the shell vossel metal and fluid temperatures temperature is 1,elow 220*F and the shall.

bo-at or above the reactor vessel is not vent ed.

temperatures shown on the limiting curves.

of

. Figs.res 3.6.1.a or 3.6.1,b.

This specification spplies when the -reactor vessel head is tensioned.

3.

The reactor vessel metal 3.

Test specimens of the reactor vesset temperatures for the botton head base. weld-t.ud heat a f fec tect cone region 'and beltl'ne region shall be metal subjected to the highest at or above the temperat'res sh7wn fluence of greater.than 1

Mev u

on the limiting curves of neutrons shall be installed in the Figure 3,6.2 during inservice reactor vessel adj ac ent to the hydrostatic or leak testing. _ The vessel wall at the coro midplane Adjusted Reference Temperature (ART)

Icvel.

The specimens rnd sample for the beltline _ region must be p rograin shall conform to ASTM l-determined from the appropriate E 185 73 to the degree possible.

l belt)Ine curve (13. 18,' or 21 EFPY) depending on the current accumula,ed number of effective full power years (EPPY),

l 9200060009 920728 PDR ADOCK 05000298.

PDR 132

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LISf1TINO CONDITIONS FOR OPERATION SURVElll3NCE REOUIREMENTS

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'3.6.A (cont *p.)

4.6.A (cont'd.)

The reactor vessel surveillance specimens shall be removed and examined to determine changes in their material properties as required-by 10 CFR 50 Appendix H.

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-4.:

The Reactor ve s:.el head. bolting-4, When the rt; actor vessel head botting studs shall-not be. under ' t ension studs are tensioned and-the reactor unless the temperature of the vessel is in a cold Conditior., the reactor-head flange and,the head is greater t vessel shell temperature immediately

' than.' 80

• F. '

below the head flanSe shall be permanently recorded.

5.

The pump in an idle recirculation Si Prior to and during startup of an loop shall not be started unlers the idic recirculation

loop,

.the.

temperatures of the coolant within remperature of the reactor coolant the idle and operat ing recirculation in the operating and-idle loops loops are within 50'F of:each other.

shall be permanently logged.

.6.

The reactorf recirculation pumps

.6.

Prior to startinr, a recirculation shall: not be started _ unless the

pump, the reactor coolani coolant-temperat'.tres between the temperatures in.the dome and in the

.9 domo-and the bottom head drain are.

bottom head drain shall be compared

within 145'F.

and permanently logged.

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3.6.A & 4.6.A BASES (cont'd) i As described in the safety analysis report, detailed stress analyses have V

been made on the reactor vessel for both steady state and transient conditions with respect to material fatigue.

The results of these j

analyses are compared to allowable stress IImits.

Requiring the coolant i

temperature in an idle recirculation loop to b.

within 50*F of the operating loop tenperature before a recirculation purnp is started assures that the changes in coolant temperature at the reactor vessel nozzles and

-bottoin head region are acceptable.

The= coolant in the bottom of the veusel is at a lower temperature than that in the upper regions of the vessel when there is no recirculation flow.

This colder water is forced up when recirculation pumps are started.

This will not result in stresses which exceed ASME Boiler and Pressure Vessel Code,Section III limits when the temperature differential is not greater than 145'F.

The first surveillance capsule was removed at 6.8 EFPY of operation and base metal, weld metal and HAZ specimens were tested.

In addition, flux wires wore tested to experimentally determine the integrated neutron flux (fluence) at the surveillance capsule location.

The test results are presented in General Electric Report MDE-103-0986.

Measured shifts in RTut of the base metal and weld metal were compared to predicted values per Regulatory Guide 1.99, Revision 1 which was in effect at that time.

The measured values were higher than predicted, so the 1.99 methods were p

modified to reflect the surveillance data. The test results for the flux wires were used with analytically determined lead factors to determine the peak end-of life EOL) fluence at the i th.

pevalue corresponding to j40 years operation (3g4 T Vessel vall dep8 EFPY) is 1.5 x 10 Wem.

Subsequent to-this evaluation, the NRC issued Regulatory Guide 1.99, Revision 2.

This revision requires that two surveillance capsules be C

tested before the test results are factored into the adjusted reference of.perature (ART) shift predictions. The adjusted reference temperature tem a beltline material is defined as the initialRTud7from lus the RT due develope.

the iNtial-to irradiation.

Therefore, the curves surveillance capsule testing were re-evaluated in accordance with the guidance provided in Regulatory Guide 1.99 Revision 2.

Based strictly on the chemistry-factors provided in Regulatory' Guide 1.99 Revision 2, and considering each beltline material chemistry and peak fluence at a given EFP f, the pressure temperature curves in Tigures 3.6.1,a and 3.6.1.b, which reficct a beltlino ART of 110'F, were determined to be valid for 21 EFPY.. Figure 3 6.2, the pressure test curve, was re-evaluated in like manner and includes curves for 13, 18-and 21 EFPY to provide more

~1exibility in pressure testine,.

Figure 3.6.2 also has a separate curve' tor the bottom head region.

The bottom head - curve does not shift with increased operation; therefore, the bottom head temperature can be monitored against lower temperature requirements than the beltline during

~

pressure testing.

The surveillance capsulo withdrawal schedule for the i

remaining snecimens is located in Section IV.2.7 of the CNS USAR.

I,

.B.

Coolant chemistry..

Materials in the primary system are primarily Type-304 stain 1ers steel and E

Ziracioy cladding. The reactor water chemistry l'.mits are established to L

. provide an environment favorable to these mateilais. Limits are placed on

. conductivity and chloride concentrations. Conductivity is limited because it can-he continuously.and reliably measured and giv'es an indication of

- abnormal conditions and the presence of unusual materials in the coolant.

Chloride limits are specified to prevent stress corrosion cracking of stainless steel.

L

' Several investigations have shown that in neutral solutions some oxyren is

-required to cause stress corrosion cracking of stainless steel, whfle in the absence of oxygen no cracking occurs.

One of these is the chloride-oxygen relationship of Williamsb where it is shown that at high chloride cohcentration little oxygen is required to cause stress corrosion cracking and.at hi chloride is cause - cracking.gh oxygen concentration little L

of stainless: steel, i-required to These measurements were determined in a wetting and urying situation using alkaline-phosphate treated boiler water and therefore, are of limited significance to BWR conditions.

They are, however, a qualitative indication of trends.

l N. L. Williams, Corrosion 13, 1957. p. 539t.

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1600 VAUD TD 21 EFPY 0

1400 Adjusted Beltline 1/4T FLAW. ART = 110*t 1200 1000 Ih k

W E 800 R

a w

5 en 600 SAFE OPE R ATING 400 REGION NON BELTLINE FW NOZ2LE LIMITS, 1/4T FLAW. RTNOT

• 30'r

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BOLT PRELOAD TEMPERATURE = BO'F FLANGE REGION HTNOT = 20*F 0

O 100 200 300 MINIMUM VESSEL METAL TEMPERfTURE (*F)

Figure 3.6.1.a liinimum Temperature for Non-Nu:' ear Heatup or Core Cooldown Following Nuclear Shutdes,

154

l 1600 l

VAUD TO 21 EFPY C

1400 1

ADJUSTED BELTINE.

1/4T FLAW, ART = 110*F 1:00 1000 3

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5 n.

800 3

5 "d

3-e EA 600 NC 4 8tLTU N4 SAFE l

FW N0ZILE UMIT5 CPERATING plt:5 40'P.114T PLAW AEGICN 8

RTuoy = 33 r 400 REDUIRED IN IV.A.3, N 10CFR50, APPE.NDIX G FLANGE REGION RTNOT

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MINIMUM PERMISS10LE 00

'* TEVPER ATURE w 80'F l7/

PER 10CFR$0 APPENDIX G I

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0 100 200 30o 1'

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MINIMUM VESSEL METAL TEMPERATURE i'F) l Figure 3.6.1.b Minimum Tc=perature for Core Cperation (Criticality; -

Includes 40CF M.argin Required by 10CTR50 appendi:: 3 155 s.

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1600 -

i BOTTOM EFPY HEAD REGION 13 18 21

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