ML19261F277: Difference between revisions
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Safety Analysis Justifying Change The reactor internals vent valves have been designed to provide a direct steam relief path in the event of a LOCA in the reactor inlet piping, from the upper plenum to the break in the inlet piping. During the reflooding phase of a LOCA transient, stea= generated from ECCS fluid coming into contact with the hot cladding vill pressurize the upper plenum, thereby opening the vent valves and allowing steam to flow through them. The rate of steam relief is calculated using a consertatively high flow resistance factor (k-factor) of 4.2 as is discussed in Topical Report BA'4-1010h. Demonstration that the vent valves vill be full-open when a pressure differential is applied across them that is lover than that obtained during the LOCA analysis is sufficient to verify that the vent valves are operational. Large Break LCCA analysis for B&W 177 FA plants demonstrating the compliance of the ECCS system to 10 CFB50.h6 has been reported in Topical Report EAW-10103 During the reflooding phase of the accident, a pressure differential in excess of 1.0 psid was maintained across the vent valves throughout the transient. Therefore, the required pressure differential necessary to hold the vent valves full-open must be shown to be no more than 1.0 psid. | Safety Analysis Justifying Change The reactor internals vent valves have been designed to provide a direct steam relief path in the event of a LOCA in the reactor inlet piping, from the upper plenum to the break in the inlet piping. During the reflooding phase of a LOCA transient, stea= generated from ECCS fluid coming into contact with the hot cladding vill pressurize the upper plenum, thereby opening the vent valves and allowing steam to flow through them. The rate of steam relief is calculated using a consertatively high flow resistance factor (k-factor) of 4.2 as is discussed in Topical Report BA'4-1010h. Demonstration that the vent valves vill be full-open when a pressure differential is applied across them that is lover than that obtained during the LOCA analysis is sufficient to verify that the vent valves are operational. Large Break LCCA analysis for B&W 177 FA plants demonstrating the compliance of the ECCS system to 10 CFB50.h6 has been reported in Topical Report EAW-10103 During the reflooding phase of the accident, a pressure differential in excess of 1.0 psid was maintained across the vent valves throughout the transient. Therefore, the required pressure differential necessary to hold the vent valves full-open must be shown to be no more than 1.0 psid. | ||
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3.1.11 EIACTC.' ::: TIE::AL3 'IE::T IAL'/ES Aonlictbility Applies to Reactor Internals Vent Valves Ob,iective To verify that no reactor internals vent valve is stuck in the open position and that each valve continues to exhibit freedcm of movement. | 3.1.11 EIACTC.' ::: TIE::AL3 'IE::T IAL'/ES Aonlictbility Applies to Reactor Internals Vent Valves Ob,iective To verify that no reactor internals vent valve is stuck in the open position and that each valve continues to exhibit freedcm of movement. | ||
Snecifications 3.1.11.1 Tne structural integrity and operability of the reactor internals vent valves shall be maintained at a level consistent with the acceptance criteria in Specification h.lo. | Snecifications 3.1.11.1 Tne structural integrity and operability of the reactor internals vent valves shall be maintained at a level consistent with the acceptance criteria in Specification h.lo. | ||
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Objective To verify that no reactor internals vent valve is stuck in the open position and that each valve continues to exhibit freedom of movement. | Objective To verify that no reactor internals vent valve is stuck in the open position and that each valve continues to exhibit freedom of movement. | ||
Specifiestion Item Test Frecuency 4:16.1 Reactor Internals De=enstrate Operability Each refueling Vent Valves By: shutdown. | Specifiestion Item Test Frecuency 4:16.1 Reactor Internals De=enstrate Operability Each refueling Vent Valves By: shutdown. | ||
: a. Conducting a remote visual inspection of visually accessible sur-faces of the valve body and disc sealing faces | : a. Conducting a remote visual inspection of visually accessible sur-faces of the valve body and disc sealing faces and evaluating any observed surfe.ce irregu-larities. | ||
and evaluating any observed surfe.ce irregu-larities. | |||
: b. Verifying that the valve is not stuck in an open position, and | : b. Verifying that the valve is not stuck in an open position, and | ||
: c. Verifying through manual actuation that the valve is fully open with a force of < h00 lbs (applied vertically upward). | : c. Verifying through manual actuation that the valve is fully open with a force of < h00 lbs (applied vertically upward). | ||
Latest revision as of 20:32, 1 February 2020
| ML19261F277 | |
| Person / Time | |
|---|---|
| Site: | Three Mile Island  |
| Issue date: | 02/03/1978 |
| From: | METROPOLITAN EDISON CO. |
| To: | |
| Shared Package | |
| ML19261F275 | List: |
| References | |
| NUDOCS 7910250720 | |
| Download: ML19261F277 (3) | |
Text
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Three Mile Island Nuclear Station, Unit 1 Operating License !!o. DPR-50 Docket No. 50-239 Technical Specification Change Request '!o. 71 The licensee requests that the attached revised page h-59 replaces the existing Technical Specification page h-59, and page 3-18b be added to the existing Technical Specifications.
Rec. sons for Chance Recuest This proposed chan6e has been initiated to meet the Cc= mission's concerns and requirements.
Safety Analysis Justifying Change The reactor internals vent valves have been designed to provide a direct steam relief path in the event of a LOCA in the reactor inlet piping, from the upper plenum to the break in the inlet piping. During the reflooding phase of a LOCA transient, stea= generated from ECCS fluid coming into contact with the hot cladding vill pressurize the upper plenum, thereby opening the vent valves and allowing steam to flow through them. The rate of steam relief is calculated using a consertatively high flow resistance factor (k-factor) of 4.2 as is discussed in Topical Report BA'4-1010h. Demonstration that the vent valves vill be full-open when a pressure differential is applied across them that is lover than that obtained during the LOCA analysis is sufficient to verify that the vent valves are operational. Large Break LCCA analysis for B&W 177 FA plants demonstrating the compliance of the ECCS system to 10 CFB50.h6 has been reported in Topical Report EAW-10103 During the reflooding phase of the accident, a pressure differential in excess of 1.0 psid was maintained across the vent valves throughout the transient. Therefore, the required pressure differential necessary to hold the vent valves full-open must be shown to be no more than 1.0 psid.
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3.1.11 EIACTC.' ::: TIE::AL3 'IE::T IAL'/ES Aonlictbility Applies to Reactor Internals Vent Valves Ob,iective To verify that no reactor internals vent valve is stuck in the open position and that each valve continues to exhibit freedcm of movement.
Snecifications 3.1.11.1 Tne structural integrity and operability of the reactor internals vent valves shall be maintained at a level consistent with the acceptance criteria in Specification h.lo.
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Apolicability Applies to Reuctor Internals Vent Valves.
Objective To verify that no reactor internals vent valve is stuck in the open position and that each valve continues to exhibit freedom of movement.
Specifiestion Item Test Frecuency 4:16.1 Reactor Internals De=enstrate Operability Each refueling Vent Valves By: shutdown.
- a. Conducting a remote visual inspection of visually accessible sur-faces of the valve body and disc sealing faces and evaluating any observed surfe.ce irregu-larities.
- b. Verifying that the valve is not stuck in an open position, and
- c. Verifying through manual actuation that the valve is fully open with a force of < h00 lbs (applied vertically upward).
Bases Verifying vent valve freedce of movement insures that coolant flov does not bypass the core through reactor internals vent valves during operation and therefore insures the conservatism of Core Protection Safety limits as de-lineated in figures 2.1-1 and 2.1-3, and the flux / flow trip setpcint.
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