ML20216D251
| ML20216D251 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 08/28/1997 |
| From: | WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| Shared Package | |
| ML20216D248 | List: |
| References | |
| RTR-NUREG-1432 NUDOCS 9709090263 | |
| Download: ML20216D251 (9) | |
Text
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pH Adjustment i
3.6.9 3.6 CONTAINMENT SY5 m c 3.6.9 pHAdjustment LCO 3.6.9 The pH adjustment shall be OPERABLE, APPLICABILITY:
MODES 1, 2, 3, and 4.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A.
The volume of A.1 Restore volume of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> trisodium phosphate trisodium phosphate to not within limit, within limit, b
B.
Required Action and B.1 Be in MODE 3.
t hours associated Completion Time of Condition A MQ not met.
3 89 B.2.1 Be in MODE g.
% hours LC030t' or persons other nA l QB B.2.2 Verify the available 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> volume of trisodium N phosphate meets 1pdk of the limit speci6ed in SR r
3.6.9.1.
9709090263 970828 PDR ADOCK 05200003 A
PDR h AP600 3.6 22 08/96 Amendment 0
pH Adjustment 3.6.9 SURVEILLANCE REQUIREMENTS
$URVEILLANCE FREQUENCY 290 SR 3.6.9.1 Verify that the pH adju nt kets 24 months cwias4 se f.11e4 ith at least f
of TSP Wnt N ^ - 3,5S:?::4G1-'. J- =amhl (Na,POA2 H.0)
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. S t, 3.4.9. 2 ystoF1 war A SAMLE FA%t rWE p H A D 3 4 s 7ef F N ir 845K E7s P O A 0fS y,4$
$0EqnnTE y& ADJab7MMT of THE fas*r %O&Arr yJ6'rEA.
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h AP600 3.6 23 08/96 Amendment 0
o pH Adjustment p 3.6.9 t 3.6 CONTAINMENT '
8 3.6.9 pHAdjustment BASES i
BACKGROUND l
The Passive Core Cooling System (PXS) includes two pH adjustment baskets which provide adjustment of the pH of the water in the containment following an accident where the containment floods.
TW M KM "M Following an accident with a large release of radioactirity, the containment pH is automatically adjusted to 5:t ::-
ad9.5,toenhanceiodineretentioninthecontainmen5^7.0 l
water.
Chemical addition is necessary to counter the affects of the boric acid contained in the safety-injection gy, tupp bies The desired pH values significantly reduces g-formatTon of elemental todine in the enntainment water, which reduces the wproduction of organic iodine and the total airborne iodine in the containment. This pH adjustment is also provided to prevent stress corrosion cracking of safety related containment components during long tem cooling.
lar trisodium phospJto- (TIP) containoa in baskels h
provt ssive anf of pH control TO N uch accidsnt #
These baskets ocated inside containment an'ilevation that is be Mhe evel. Najt ral-recircu a ion of gg 47g > wa er de the containme y.en'by the core dec haat
- 5" pr (mixing to achiev ifo CrystaJ1tn TSN h
( a,PO 12Rio) s nitially loaded into the Qecauseit is hydrate pdhin would (anhydrous Nai undergo less physjse rd i..
d chang ity inside containment.[ PO, Va result of the
~
APPLICABLE in the event of a Design Basis Accident (DBA), iodine may be SAFETY ANALYSES released from the fuel to containment. To limit this iodine release from containment, the pH of the water in the containment sump is adjusted by the addition of TSP, Adjusting the sump water to neutral or alkaline pH will augment the retention of the iodine, and thus reduce the iodine available to leak to the environment.
pH adjustment satisfies Criterion 3 of the NRC Policy Statement.
(continued)
] 00 B 3.6 47 08/96 Amendment 0
DASES 3.
6.9 BACKGROUND
PAGE D 3.647 INSERT Second paragraph
... and acids produced in the post LOCA environment (nitric acid from the l
irradiation of water and air, and hydrochloric acid from irradiation and pyrolysis of elect.ic cable insulation),
1 INSERT Third paragraph Dodecahydrate trisodium phosphate (TSP) contained in baskets provides a l
passive means of pH control for such accidents. The baskets are made of l
stainless steel with a mesh front that readily permits contact with water, j
These baskets are located inside containment at an elevation that is below l
Lhe minimum floodup level. The baskets are placed at least a foot above the l
floor to reduce the chance that water spills will dissolve the TSP. Natural -
l recirculation of water inside the containment, following a LOCA, is driven by the core degay herd and provides m:xing to achieve a uniform pH.
pts c$odecahydratn$s82ium phosphate (Na3PO.12110)is initially loaded into 3
the baskets because it is hydrated and will undergo less physical and chemical change than would anhydrous Na3PO as a result of the humidity 4
inside containment. (Refs. I and 2)
C pH Adjustment I 306.9 I
BASES (continued)
~
i LCO TherequirementtomaintainthepHadjustmentbaskets OPERA 8LE with the required volems of TSP assures that for DBA releases of iodine into containment the pH of the containment sump will be adjusted to ennance the retention of the iodine.
A required volume is specified instead of mass because it is not feasible to weigh the TSP in the containment.
The minimum required volume is based on the manufactured density' of TSP.
This is conservative because the density of TSP may increase after installation due to compaction.
APPL!CABILITY In MODES 1, 2, 3, and 4 a DBA could cause release of radioactive iodine to containment requiring pH adjustment.
The pH adjustment baskets assist in reducing the airborne iodine fission product inventory available for release to the environment.
In MODES 5 and 6, the probability and consequences of the'se events are reduced due to the pressure and temperature limitations of these MODES. Taus, pH adjustment is not required to be OPERABLE in MODES 5 ai.d 6.
ACTIONS M
If the TSP volume in the baskets is not within limits, the iodine retention may be less than'that assumed in the accident analysis for the limiting 08A.
Due to the very low probability that the volume of TSP may change, the variations is expected to be minor such that the required capability is substantially available.
The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time for restoration to within limits is consistent with times applied to minor degradations of ECCS parameters.
B.1 and B.2 5
If the Required Actions and associated Compi ion Times are not met, the plant must be brought to MODE / where the probability and consequences on an event are minimized.- To achieve this status, tb plant must be brought to at least (continued) b AP600 B 3.6 48 08/96 Amendment 0
pH Adjustment 8 3.6.9 4
BA$ts ACTIONS B.1 and B.2 (continued)
MODE 3withinkhoursandtoMODE within hours.
The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.
I T s-b SURVElllANCE 5M. L9rt REQUIREMENTS
/N]
l Thi survetT1'ince uires that a vi al inspection be per o Qh adjustment baskets verify that the total volume of 4Lis greater than the min specifJ d.
i RE#McE This inspecMon is rle utret to ensure thajtsaks iTe' WiW ntainm af have not spra edin-the beslFets and caus TSP J
dis ion.
The probabi Idi folutinn of the durla'g no l an.#
tion is very low be of the loc % tion, paner the baskets. T month ency' is ennstnent with freque appl d to this type of deTTon in onen' 4W*nti, i
REFERENCES tme.
A
/N $64t.Y b AP600 B 3.6 49 08/96 Amendment 0 oi.~i m l
x
]
O BASES 3.6.9 ACTIONS PAGE B 3.6 49 I
INSERT B.1 and B.2 An alternative to cooling the plant to MODE 5 conditions is to verify within a Completion Time of 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> that 70% of the required TSP volume is available while in MODE 3. The reduced TSP volume is adequate in MODE -
3, considering that the required volume is based on severe accident conditions and that no MODE 3 DBAs are predicted to rer. ult in a significant fission product release.
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BASES 3.6.9 SURVEILLANCE REQUIREMENTS
' PAO'E B 3.6 49 INSERT SR 3.6.9.1 The minimum amount of TSP is (240) ft. A volume is specified eince it is 8
not feasible to weigh the TSP contained in the pH acUustment baskets. This volume is based on providing sufHelent TSP to buffer the post accident containment water to a minimum pH of 7.0.- Additionally, the TSP volume is based on treating the maximum volume _of post accident water (l765,500) l gallons) containing the maximum amount of boron (13007] ppm) as well as I
other sources of acid. The minimum required mass of TSP is [11,5501
-pounds.
The minimum required volume of TSP is based on this minimum required mass of TSP, the minimum density of TSP plus margin to account for degradation of TSP during plant operation. The minimum TSP density is based on the manufactured density, since ? e density may increase and the h
volume decrease, during plant operation (ue to agglomeration from-humidity inside the containment. The minimum required TSP volume also has about 10% margin to account for degradation of TSP during plant operation.
SR 3.6.9.2 Testing must be performed to ensure the buffering ability of the TSP after i
exposure to the containment environment. A representative sample of 5 (1.25] grams _of TSP from one of the bashcts La submerged in 21 liter of water at a boron concentration of 2 [3007] ppm at the standard temperature of 25
- 5'C. The solution pH should be raised to 2 7.0.
The minimum required amount of TSP (11,550] pounds is sufficient to buffer the maximum amount of boron (3007) ppm, the maximum amount of other acids and the maximum amount of water [765,500] gallons that can exist in the containment following an accident and achieve a minimum pH of 7.0, Of this amount of TSP, (71241 pounds is required to buffer the boren, without consideration for other sources of acid. The representative sample weight is based on M
(,7 1 4 P o b d 5 W
I BASES 3.
6.9 REFERENCES
PA0k B 3.6-49 i
INSERT h 1.
SSAR Section 0.3.2.1.4, Containment pH Cor. trol 2.
SSAR Section 6.3.2.2.4, pH Adjustment Baskets.
I 3.
SSAR Section 15.6.5.3.1, Identi6 cation of Cause and Accident Description.
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